|Which statement is true regarding bearings used in high-powered reciprocating aircraft engines? The outer race of a single-row, self-aligning ball bearing will always have a radius equal to the radius of the balls. There is less rolling friction when ball bearings are used than when roller bearings are employed. Crankshaft bearings are generally of the ball-type due to their ability to withstand extreme loads without overheating.
A condition that can occur in radial engines but is unlikely to occur in horizontally opposed engines is oil-fouled spark plug. valve overlap. hydraulic lock.
Which condition would be the least likely to be caused by failed or failing engine bearings? Excessive oil consumption. High oil temperatures. Low oil temperatures.
What is the principal advantage of using propeller reduction gears? To enable the propeller RPM to be increased without an accompanying increase in engine RPM. To enable the engine RPM to be increased with an accompanying increase in power and allow the propeller to remain at a lower, more efficient RPM. To enable the engine RPM to be increased with an accompanying increase in propeller RPM.
Which of the following will decrease volumetric efficiency in a reciprocating engine?
1. Full throttle operation.
2. Low cylinder head temperatures.
3. Improper valve timing.
4. Sharp bends in the induction system.
5. High carburetor air temperatures. 2, 4, and 5. 1, 2, 3, and 4. 3, 4, and 5.
Which of the following is a characteristic of a thrust bearing used in most radial engines? Tapered roller. Double-row ball. Deep-groove ball.
Which bearing is least likely to be a roller or ball bearing? Rocker arm bearing (overhead valve engine). Master rod bearing (radial engine). Crankshaft main bearing (radial engine).
The operating temperature valve clearance of a radial engine as compared to cold valve clearance is greater. less. the same.
A nine-cylinder engine with a bore of 5.5 inches and a stroke of 6 inches will have a total piston displacement of 740 cubic inches. 1,425 cubic inches. 1,283 cubic inches.
The five events of a four-stroke cycle engine in the order of their occurrence are intake, ignition, compression, power, and exhaust. intake, compression, power, ignition, and exhaust. intake, compression, ignition, power, and exhaust.
The primary concern in establishing the firing order for an opposed engine is to provide for balance and eliminate vibration to the greatest extent possible. keep power impulses on adjacent cylinders as far apart as possible in order to obtain the greatest mechanical efficiency. keep the power impulses on adjacent cylinders as close as possible in order to obtain the greatest mechanical efficiency.
If fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed 20 to 30° before top center at the end of the compression stroke. when the exhaust valve opens at the end of the power stroke. just after top center at the beginning of the power stroke.
Grinding the valves of a reciprocating engine to a feather edge is likely to result in normal operation and long life. excessive valve clearance. preignition and burned valves.
Which statement is correct regarding engine crankshafts? Moveable counterweights serve to reduce the dynamic vibrations in an aircraft reciprocating engine. Moveable counterweights serve to reduce the torsional vibrations in an aircraft reciprocating engine. Moveable counterweights are designed to resonate at the natural frequency of the crankshaft.
On which strokes are both valves on a four-stroke cycle reciprocating aircraft engine open? Power and exhaust. Intake and compression. Exhaust and intake.
Which type of bearings are generally used for connecting rods and cam shafts? Plain. Roller. Ball.
The actual power delivered to the propeller of an aircraft engine is called friction horsepower. brake horsepower. indicated horsepower.
Cam-ground pistons are installed in some aircraft engines to provide a better fit at operating temperatures. act as a compensating feature so that a compensated magneto is not required. equalize the wear on all pistons.
Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust valves seated.
Intake opens 15°: BTDC.
Exhaust opens 70°: BBDC.
Intake closes 45°: ABDC.
Exhaust closes 10°: ATDC. 290°. 245°. 25°.
Some aircraft engine manufacturers equip their product with choked or taper-ground cylinders in order to provide a straight cylinder bore at operating temperatures. flex the rings slightly during operation and reduce the possibility of the rings sticking in the grooves. increase the compression pressure for starting purposes.
An aircraft reciprocating engine using hydraulic valve lifters is observed to have no clearance in its valve-operating mechanism after the minimum inlet oil and cylinder head temperatures for takeoff have been reached. When can this condition be expected? During normal operation. When the lifters become deflated. As a result of carbon and sludge becoming trapped in the lifter and restricting its motion.
What tool is generally used to measure the crankshaft rotation in degrees? Dial indicator. Timing disk. Prop Protractor.
If an engine with a stroke of 6 inches is operated at 2,000 RPM, the piston movement within the cylinder will be at maximum velocity around TDC. constant during the entire 360° of crankshaft travel. at maximum velocity 90° after TDC.
If the intake valve is opened too early in the cycle of operation of a four-stroke cycle engine, it may result in improper scavenging of exhaust gases. engine kickback. backfiring into the induction system.
Some cylinder barrels are hardened by nitriding. honing. quenching.
Which statement is correct regarding a four-stroke cycle aircraft engine? The intake valve closes on the compression stroke. The exhaust valve opens on the exhaust stroke. The intake valve closes on the intake stroke.
On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur? Near the center of the cylinder where piston velocity is greatest. Near the top of the cylinder. Wear is normally evenly distributed.
During overhaul, reciprocating engine exhaust valves are checked for stretch with a suitable inside spring caliper. with a contour or radius gauge. by placing the valve on a surface plate and measuring its length with a vernier height gauge.
When is the fuel/air mixture ignited in a conventional reciprocating engine? When the piston has reached top dead center of the intake stroke. Shortly before the piston reaches the top of the compression stroke. When the piston reaches top dead center on the compression stroke.
Ignition occurs at 28° BTDC on a certain four-stroke cycle engine, and the intake valve opens at 15° BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? (Consider one cylinder only.) 707°. 373°. 347°.
What is the purpose of the safety circlet installed on some valve stems? To hold the valve guide in position. To hold the valve spring retaining washer in position. To prevent valves from falling into the combustion chamber.
Valve overlap is defined as the number of degrees of crankshaft travel during which both valves are off their seats. between the closing of the intake valve and the opening of the exhaust valve. during which both valves are on their seats.
The valve clearance of an engine using hydraulic lifters, when the lifters are completely flat, or empty, should not exceed 0.00 inch. a specified amount above zero. a specified amount below zero.
If the exhaust valve of a four-stroke cycle engine is closed and the intake valve is just closed, the piston is on the intake stroke. power stroke. compression stroke.
How many of the following are factors in establishing the maximum compression ratio limitations of an aircraft engine?
1. Detonation characteristics of the fuel used.
2. Design limitations of the engine.
3. Degree of supercharging.
4. Spark plug reach. Four. Two. Three.
Full-floating piston pins are those which allow motion between the pin and the piston. both the piston and the large end of the connecting rod. both the piston and the small end of the connecting rod.
The primary purpose in setting proper valve timing and overlap is to permit the best possible charge of fuel/air mixture into the cylinders. gain more thorough exhaust gas scavenging. obtain the best volumetric efficiency and lower cylinder operating temperatures.
If the hot clearance is used to set the valves when the engine is cold, what will occur during operation of the engine? The valves will open early and close early. The valves will open late and close early. The valves will open early and close late.
What is the purpose of installing two or more springs on each valve in an aircraft engine? To equalize side pressure on the valve stem. To eliminate valve spring vibration or surging. To help equalize valve face loading.
During overhaul, the disassembled parts of an engine are usually degreased with some form of mineral spirits solvent rather than water-mixed degreasers primarily because solvent degreasers are much more effective. water-mixed degreaser residues may cause engine oil contamination in the overhauled engine. water-mixed degreasers cause corrosion.
Why does the smoothness of operation of an engine increase with a greater number of cylinders? The power impulses are spaced closer together. The power impulses are spaced farther apart. The engine has larger counterbalance weights.
Compression ratio is the ratio between the piston travel on the compression stroke and on the intake stroke. combustion chamber pressure on the combustion stroke and on the exhaust stroke. cylinder volume with piston at bottom dead center and at top dead center.
If the crankshaft runout readings on the dial indicator are plus .002 inch and minus .003 inch, the runout is .005 inch. plus .001 inch. minus .001 inch.
(1) Cast iron piston rings may be used in chrome-plated cylinders.
(2) Chrome-plated rings may be used in plain steel cylinders.
Regarding the above statements, only No. 1 is true. neither No. 1 nor No. 2 is true. both No. 1 and No. 2 are true.
How is proper end-gap clearance on new piston rings assured during the overhaul of an engine? By accurately measuring and matching the outside diameter of the rings with the inside diameter of the cylinders. By using rings specified by the engine manufacturer. By placing the rings in the cylinder and measuring the end-gap with a feeler gauge.
The volume of a cylinder equals 70 cubic inches when the piston is at bottom center. When the piston is at the top of the cylinder, the volume equals 10 cubic inches. What is the compression ratio? 10:7 10:1 7:1.
When cleaning aluminum and magnesium engine parts, it is inadvisable to soak them in solutions containing soap because some of the soap will become impregnated in the surface of the material and subsequently cause engine oil contamination and foaming. the soap can chemically alter the metals causing them to become more susceptible to corrosion. the parts can be destroyed by dissimilar metal electrolytic action if they are placed together in the solution for more than a few minutes.
What is the purpose of a power check on a reciprocating engine? To check magneto drop. To determine satisfactory performance. To determine if the fuel/air mixture is adequate.
What will be the likely result if the piston ring gaps happen to be aligned when performing a differential-pressure compression check on a cylinder? Little or no effect. The rings will not be seated. A worn or defective ring(s) indication.
Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine? Reduced valve overlap period. Intake and exhaust valves will open early and close late. A power increase by shortening the exhaust event.
The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by controlling oil flow through the oil cooler. recirculating hot oil back through the sump. controlling air flow through the oil cooler.
Which of the following would indicate a general weak-engine condition when operated with a fixed-pitch propeller or test club? Lower than normal static RPM, full throttle operation. Manifold pressure lower at idle RPM than at static RPM. Lower than normal manifold pressure for any given RPM.
What is required by 14 CFR Part 43 Appendix D when performing an annual/100-hour inspection on a reciprocating engine aircraft? Magneto timing check. Cylinder compression check. Valve clearance check.
After spark plugs from an opposed engine have been serviced, in what position should they be reinstalled? Next in firing order to the one from which they were removed. Swapped bottom to top. Next in firing order to the one from which they were removed and swapped bottom to top.
As the pressure is applied during a reciprocating engine compression check using a differential pressure tester, what would a movement of the propeller in the direction of engine rotation indicate? The piston was on compression stroke. The piston was on exhaust stroke. The piston was positioned past top dead center.
Excessive valve clearance results in the valves opening late and closing early. early and closing late. late and closing late.
During routine inspection of a reciprocating engine, a deposit of small, bright, metallic particles which do not cling to the magnetic drain plug is discovered in the oil sump and on the surface of the oil filter. This condition may be a result of abnormal plain type bearing wear and is cause for further investigation. is probably a result of ring and cylinder wall wear and is cause for engine removal and/or overhaul. is normal in engines utilizing plain type bearings and aluminum pistons and is not cause for alarm.
A characteristic of dyna-focal engine mounts as applied to aircraft reciprocating engines is that the shock mounts eliminate the torsional flexing of the powerplant. engine attaches to the shock mounts at the engine's center of gravity. shock mounts point toward the engine's center of gravity.
If metallic particles are found in the oil filter during an inspection, it is an indication of normal engine wear unless the particles are nonferrous. the cause should be identified and corrected before the aircraft is released for flight. it is an indication of normal engine wear unless the deposit exceeds a specified amount.
If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is low oil supply. broken or weak pressure relief valve spring. air lock in the scavenge pump intake.
What special procedure must be followed when adjusting the valves of an engine equipped with a floating cam ring? Adjust valves when the engine is hot. Adjust all exhaust valves before intake valves. Eliminate cam bearing clearance when making valve adjustment.
Which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances? The valves will not seat positively during start and engine warmup. The further decrease in valve clearance that occurs as engine temperatures increase will cause damage to the valve-operating mechanism. The valves will remain closed for longer periods than specified by the engine manufacturer.
Excessive valve clearances will cause the duration of valve opening to increase for both intake and exhaust valves. decrease for both intake and exhaust valves. decrease for intake valves and increase for exhaust valves.
What does valve overlap promote? Lower intake manifold pressure and temperatures. A backflow of gases across the cylinder. Better scavenging and cooling characteristics.
At what speed must a crankshaft turn if each cylinder of a four-stroke cycle engine is to be fired 200 times a minute? 800 RPM. 1,600 RPM. 400 RPM.
Engine crankshaft runout is usually checked
1. during engine overhaul.
2. during annual inspection.
3. after a 'prop strike' or sudden engine stoppage.
4. during 100-hour inspection. 1, 3, and 4. 1 and 3. 1, 2 and 3.
Before attempting to start a radial engine that has been shut down for more than 30 minutes, turn the propeller by hand three or four revolutions in the opposite direction of normal rotation to check for liquid lock. turn the ignition switch on before energizing the starter. turn the propeller by hand three to four revolutions in the normal direction of rotation to check for liquid lock.
An engine misses in both the right and left positions of the magneto switch. The quickest method for locating the trouble is to check for one or more cold cylinders. perform a compression check. check each spark plug.
A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates a cracked exhaust stack. exhaust valve blow-by. worn piston rings.
If the oil pressure of a cold engine is higher than at normal operating temperatures, the oil system relief valve should be readjusted. engine's lubrication system is probably operating normally. oil dilution system should be turned on immediately.
If an engine operates with a low oil pressure and a high oil temperature, the problem may be caused by a leaking oil dilution valve. sheared oil pump shaft. clogged oil cooler annular jacket.
Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)? A mixture leaner than a rich best-power mixture of .085. A mixture richer than a full-rich mixture of .087. A mixture leaner than a manual lean mixture of .060.
If an engine cylinder is to be removed, at what position in the cylinder should the piston be? Bottom dead center. Top dead center. Halfway between top and bottom dead center.
The horsepower developed in the cylinders of a reciprocating engine is known as the shaft horsepower. indicated horsepower. brake horsepower.
Engine operating flexibility is the ability of the engine to deliver maximum horsepower at a specific altitude. meet exacting requirements of efficiency and low weight per horsepower ratio. run smoothly and give the desired performance at all speeds.
Standard aircraft cylinder oversizes usually range from 0.010 inch to 0.030 inch. Oversize on automobile engine cylinders may range up to 0.100 inch. This is because aircraft engine cylinders have more limited cooling capacity. have relatively thin walls and may be nitrided. operate at high temperatures.
If the ignition switch is moved from BOTH to either LEFT or RIGHT during an engine ground check, normal operation is usually indicated by a slight increase in manifold pressure. bump in propeller RPM. drop in torque meter pressure indication.
During ground check an engine is found to be rough-running, the magneto drop is normal, and the manifold pressure is higher than normal for any given RPM. The trouble may be caused by several spark plugs fouled on different cylinders. a leak in the intake manifold. a dead cylinder.
What is the best indication of worn valve guides? High oil consumption. Low compression. Low oil pressure.
By use of a differential pressure compression tester, it is determined that the No. 3 cylinder of a nine-cylinder radial engine will not hold pressure after the crankshaft has been rotated 260° from top dead center compression stroke No. 1 cylinder. How can this indication usually be interpreted? A normal indication. Exhaust valve blow-by. A damaged exhaust valve or insufficient exhaust valve clearance.
When does valve overlap occur in the operation of an aircraft reciprocating engine? At the end of the exhaust stroke and the beginning of the intake stroke. At the end of the power stroke and the beginning of the exhaust stroke. At the end of the compression stroke and the beginning of the power stroke.
What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines? Increased strength and resistance to cracking. Reduced valve operating temperatures. Greater resistance to deterioration at high valve temperatures.
Valve clearance changes on opposed-type engines using hydraulic lifters are accomplished by rocker arm adjustment. rocker arm replacement. push rod replacement.
What is likely to occur if a reciprocating engine is operated at high power settings before it is properly warmed up? Oil starvation of bearings and other parts. Excessive engine oil pressure. Thermal shock of cylinders.
An increase in manifold pressure with a constant RPM will cause the bearing load in an engine to decrease. remain relatively constant. increase.
Direct mechanical push-pull carburetor heat control linkages should normally be adjusted so that the stop located on the diverter valve will be contacted before the stop at the control lever is reached in both HOT and COLD positions. before the stop at the control lever is reached in the HOT position and after the stop at the control lever is reached in the COLD position. after the stop at the control lever is reached in both HOT and COLD positions.
Reduced air density at high altitude has a decided effect on carburetion, resulting in a reduction of engine power by excessively enriching the fuel/air mixture. excessively leaning the fuel/air mixture. reducing fuel vaporization.
Increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following? Decreased engine power at a constant RPM and manifold pressure. Increased power output due to increased volumetric efficiency. A leaning effect on engines which use non-automatic carburetors.
(1) Preignition is caused by improper ignition timing.
(2) Detonation occurs when an area of the combustion chamber becomes incandescent and ignites the fuel/air mixture in advance of normal timed ignition.
Regarding the above statements, only No. 1 is true. both No. 1 and No. 2 are true. neither No. 1 nor No. 2 is true.
Which of the following engine servicing operations generally requires engine pre-oiling prior to starting the engine? Engine oil and filter change. Engine installation. Replacement of oil lines.
During the inspection of an engine control system in which push-pull control rods are used, the threaded rod ends should ensure that the safety wire passes thru the hole in shank of the rod-end. be checked for thread engagement of at least two threads but not more than four threads. be checked for the amount of thread engagement by means of the inspection holes.
Which of the following conditions would most likely lead to detonation? Late ignition timing. Use of fuel with too high an octane rating. Use of fuel with too low an octane rating.
An unsupercharged aircraft reciprocating engine, operated at full throttle from sea level, to 10,000 feet, provided the RPM is unchanged, will lose power due to the reduced volume of air drawn into the cylinders. produce constant power due to the same volume of air drawn into the cylinders. lose power due to the reduced density of the air drawn into the cylinders.
Which of the following would most likely cause a reciprocating engine to backfire through the induction system at low RPM operation? Idle mixture too rich. Clogged derichment valve. Lean mixture.
How may it be determined that a reciprocating engine with a dry sump is pre-oiled sufficiently? The engine oil pressure gauge will indicate normal oil pressure. Oil will flow from the engine return line or indicator port. When the quantity of oil specified by the manufacturer has been pumped into the engine.
What is the basic operational sequence for reducing the power output of an engine equipped with a constant-speed propeller? Reduce the RPM, then the manifold pressure. Reduce the manifold pressure, then retard the throttle to obtain the correct RPM. Reduce the manifold pressure, then the RPM.
Which statement pertaining to fuel/air ratios is true? The mixture ratio which gives the best power is richer than the mixture ratio which gives maximum economy. A rich mixture is faster burning than a normal mixture. The mixture ratio which gives maximum economy may also be designated as best power mixture.
Backfiring through the carburetor generally results from the use of an excessively lean mixture. excessively atomized fuel. an excessively rich mixture.
Which of these conditions will cause an engine to have an increased tendency to detonate?
1. High manifold pressure.
2. High intake air temperature.
3. Engine overheated.
4. Late ignition timing. 1, 4. 1, 2, 3. 1, 2, 3, 4.
When will small induction system air leaks have the most noticeable effect on engine operation? At high RPM. At maximum continuous and takeoff power settings. At low RPM.
To reduce the power output of an engine equipped with a constant-speed propeller and operating near maximum BMEP, the manifold pressure is reduced with the throttle control before the RPM is reduced with the propeller control. manifold pressure is reduced with the propeller control before the RPM is reduced with the throttle control. RPM is reduced with the propeller control before the manifold pressure is reduced with the throttle control.
One of the best indicators of reciprocating engine combustion chamber problems is excessive engine vibration. starting difficulties. spark plug condition.
What could cause excessive pressure buildup in the crankcase of a reciprocating engine? Plugged crankcase breather. Improper warmup operation. An excessive quantity of oil.
Excessive valve clearance in a piston engine increases valve overlap. increases valve opening time. decreases valve overlap.
To what altitude will a turbo charged engine maintain sea level pressure? Critical altitude. Service ceiling. Pressure altitude.
If air is heard coming from the crankcase breather or oil filler during a differential compression check, what is this an indication of? Exhaust valve leakage. Intake valve leakage. Piston ring leakage.
One cause of afterfiring in an aircraft engine is sticking intake valves. an excessively lean mixture. an excessively rich mixture.
At what point in an axial-flow turbojet engine will the highest gas pressures occur? At the turbine entrance. Within the burner section. At the compressor outlet.
One function of the nozzle diaphragm in a turbine engine is to Decrease the velocity of exhaust gases. Center the fuel spray in the combustion chamber. Direct the flow of gases to strike the turbine blades at the desired angle.
What is the profile of a turbine engine compressor blade? The leading edge of the blade. A reduced blade tip thickness. The curvature of the blade root.
The fan rotational speed of a dual axial compressor forward fan engine is the same as the low-pressure compressor. forward turbine wheel. high-pressure compressor.
The abbreviation Pt7 used in turbine engine terminology means the total inlet pressure. pressure and temperature at station No. 7. the total pressure at station No. 7.
The blending of blades and vanes in a turbine engine is usually accomplished only at engine overhaul. should be performed parallel to the length of the blade using smooth contours to minimize stress points. may sometimes be accomplished with the engine installed, ordinarily using power tools.
What turbine engine section provides for proper mixing of the fuel and air? Combustion section. Compressor section. Diffuser section.
In a gas turbine engine, combustion occurs at a constant volume. pressure. density.
Which statement is true regarding jet engines? At the lower engine speeds, thrust increases rapidly with small increases in RPM. At the higher engine speeds, thrust increases rapidly with small increases in RPM. The thrust delivered per pound of air consumed is less at high altitude than at low altitude.
Some high-volume turboprop and turbojet engines are equipped with two-spool or split compressors. When these engines are operated at high altitudes, the low-pressure rotor will increase in speed as the compressor load decreases in the lower density air. throttle must be retarded to prevent overspeeding of the high-pressure rotor due to the lower density air. low-pressure rotor will decrease in speed as the compressor load decreases in the lower density air.
Turbine nozzle diaphragms located on the upstream side of each turbine wheel, are used in the gas turbine engine to decrease the velocity of the heated gases flowing past this point. direct the flow of gases parallel to the vertical line of the turbine blades. increase the velocity of the heated gases flowing past this point.
Where is the highest gas pressure in a turbojet engine? At the outlet of the tailpipe section. At the entrance of the turbine section. In the entrance of the burner section.
An exhaust cone placed aft of the turbine in a jet engine will cause the pressure in the first part of the exhaust duct to increase and the velocity to decrease. increase and the velocity to increase. decrease and the velocity to increase.
What is the function of the stator vane assembly at the discharge end of a typical axial-flow compressor? To straighten airflow to eliminate turbulence. To direct the flow of gases into the combustion chambers. To increase air swirling motion into the combustion chambers.
The turbine section of a jet engine increases air velocity to generate thrust forces. utilizes heat energy to expand and accelerate the incoming gas flow. drives the compressor section.
When starting a turbine engine, a hot start is indicated if the exhaust gas temperature exceeds specified limits. an excessively lean mixture is likely to cause a hot start. release the starter switch as soon as indication of light-off occurs.
In the dual axial-flow or twin spool compressor system, the first stage turbine drives the N(1) and N(2) compressors. N(2) compressor. N(1) compressor.
Which of the following may be used to mark turbine engine components exposed to high temperatures? Grease or wax pencil. Layout dye. Graphite lead pencil.
When starting a turbine engine, a hung start is indicated if the engine exhaust gas temperature exceeds specified limits. fails to reach idle RPM. N1 is normal, but N2 is low.
What are the two basic elements of the turbine section in a turbine engine? Impeller and diffuser. Hot and cold. Stator and rotor.
The function of the exhaust cone assembly of a turbine engine is to collect the exhaust gases and act as a noise suppressor. swirl and collect the exhaust gases into a single exhaust jet. straighten and collect the exhaust gases into a solid exhaust jet.
What are the two functional elements in a centrifugal compressor? Turbine and compressor. Bucket and expander. Impeller and diffuser.
What must be done after the fuel control unit has been replaced on an aircraft gas turbine engine? Perform a full power engine run to check fuel flow. Recalibrate the fuel nozzles. Retrim the engine.
If, during inspection at engine overhaul, ball or roller bearings are found to have magnetism but otherwise have no defects, they cannot be used again. are in an acceptable service condition. must be degaussed before use.
A turbine engine compressor which contains vanes on both sides of the impeller is a double entry centrifugal compressor. double entry axial-flow compressor. single entry axial-flow compressor.
What is the first engine instrument indication of a successful start of a turbine engine? A rise in engine RPM. A rise in oil temperature. A rise in the exhaust gas temperature.
Some engine manufacturers of twin spool gas turbine engines identify turbine discharge pressure in their maintenance manuals as Pt7. Pt2. Tt7.
Who establishes the recommended operating time between overhauls (TBO) of a turbine engine used in general aviation? Engine manufacturer. TBO does not apply to turbine engines. Aircraft manufacturer.
The basic gas turbine engine is divided into two main sections: the cold section and the hot section.
(1) The cold section includes the engine inlet, compressor, and turbine sections.
(2) The hot section includes the combustor, diffuser, and exhaust sections.
Regarding the above statements, only No. 1 is true. only No. 2 is true. neither No. 1 nor No. 2 is true.
(1) Welding and straightening of turbine engine rotating airfoils does not require special equipment.
(2) Welding and straightening of turbine engine rotating airfoils is commonly recommended by the manufacturer.
Regarding the above statements, only No. 1 is true. only No. 2 is true. neither No. 1 nor No. 2 is true.
Turbine engine components exposed to high temperatures generally may NOT be marked with
1. layout dye.
2. commercial felt tip marker.
3. wax or grease pencil.
5. graphite lead pencil. 1, 2, and 3. 3 and 5. 4 and 5.
Who establishes mandatory replacement times for critical components of turbine engines? Engine manufacturer. Component manufacturer. Engine manufacturer.
Main bearing oil seals used with turbine engines are usually what type(s)? Labyrinth and/or carbon rubbing. Teflon and synthetic rubber. Labyrinth and/or silicone rubber.
How does a dual axial-flow compressor improve the efficiency of a turbojet engine? More turbine wheels can be used. Higher compression ratios can be obtained. The velocity of the air entering the combustion chamber is increased.
Three types of turbine blades are impulse, converging, and impulse-converging. impulse, reaction, and impulse-reaction. impulse, diverging, and impulse-diverging.
Which statements are true regarding aircraft engine propulsion?
1. An engine driven propeller imparts a relatively small amount of acceleration to a large mass of air.
2. Turbojet and turbofan engines impart a relatively large amount of acceleration to a smaller mass of air.
3. In modern turboprop engines, nearly 50 percent of the exhaust gas energy is extracted by turbines to drive the propeller and compressor with the rest providing exhaust thrust.1, 2, 3. 1, 2, 3. 1, 2. 1, 3.
An advantage of the axial-flow compressor is its low starting power requirements. low weight. high peak efficiency.
What is one purpose of the stator blades in the compressor section of a turbine engine? Stabilize the pressure of the airflow. Control the direction of the airflow. Increase the velocity of the airflow.
What is the purpose of the diffuser section in a turbine engine? To increase pressure and reduce velocity. To convert pressure to velocity. To reduce pressure and increase velocity.
Where do stress rupture cracks usually appear on turbine blades? Across the blade root, parallel to the fir tree. Along the leading edge, parallel to the edge. Across the leading or trailing edge at a right angle to the edge length.
In which type of turbine engine combustion chamber is the case and liner removed and installed as one unit during routine maintenance? Can. Can annular. Annular.
The diffuser section of a jet engine is located between the burner section and the turbine section. station No. 7 and station No. 8. the compressor section and the burner section.
When the leading edge of a first-stage turbine blade is found to have stress rupture cracks, which of the following should be suspected? Faulty cooling shield. Overtemperature condition. Overspeed condition.
Turbine blades are generally more susceptible to operating damage than compressor blades because of the high probability of carbon deposits. exposure to high temperatures. less exposure to solution during engine pressure wash.
Which of the following is the ultimate limiting factor of turbine engine operation? Compressor inlet air temperature. Turbine inlet temperature. Burner-can pressure.
The recurrent ingestion of dust or other fine airborne particulates into a turbine engine can result in foreign object damage to the compressor section. the need for less frequent abrasive grit cleaning of the engine. erosion damage to the compressor and turbine sections.
Which of the following engine variables is the most critical during turbine engine operation? Compressor inlet air temperature. Compressor RPM. Turbine inlet temperature.
Reduced blade vibration and improved airflow characteristics in gas turbines are brought about by fir-tree blade attachment. impulse type blades. shrouded turbine rotor blades.
Which turbine engine compressor offers the greatest advantages for both starting flexibility and improved high-altitude performance? Dual-stage, centrifugal-flow. Split-spool, axial-flow. Single-spool, axial-flow.
Jet engine turbine blades removed for detailed inspection must be reinstalled in a specified slot 180° away. a specified slot 90° away in the direction of rotation. the same slot.
An advantage of the centrifugal-flow compressor is its high pressure rise per stage. ram efficiency. peak efficiency.
The highest heat-to-metal contact in a jet engine is the burner cans. turbine inlet guide vanes. turbine blades.
Which two elements make up the axial-flow compressor assembly? Rotor and stator. Compressor and manifold. Stator and diffuser.
The two types of centrifugal compressor impellers are single entry and double entry. rotor and stator. impeller and diffuser.
Between each row of rotating blades in a turbine engine compressor, there is a row of stationary blades which act to diffuse the air. These stationary blades are called buckets. rotors. stators.
Standard sea level pressure is 29.00" Hg. 29.29" Hg. 29.92" Hg.
Using standard atmospheric conditions, the standard sea level temperature is 59°F. 59°C. 29°C.
When aircraft turbine blades are subjected to excessive heat stress, what type of failures would you expect? Bending and torsion. Torsion and tension. Stress rupture.
In an axial-flow compressor, one purpose of the stator vanes at the discharge end of the compressor is to straighten the airflow and eliminate turbulence. increase the velocity and prevent swirling and eddying. decrease the velocity, prevent swirling, and decrease pressure.
Compressor field cleaning on turbine engines is performed primarily in order to prevent engine oil contamination and subsequent engine bearing wear or damage. facilitate flight line inspection of engine inlet and compressor areas for defects or FOD. prevent engine performance degradation, increased fuel costs, and damage or corrosion to gas path surfaces.
Hot section inspections for many modern turbine engines are required only at engine overhaul. only when an overtemperature or overspeed has occurred. on a time or cycle basis.
A purpose of the shrouds on the turbine blades of an axial-flow engine is to reduce vibration. increase tip speed. reduce air entrance.
In a dual axial-flow compressor, the first stage turbine drives N(2) compressor. N(1) compressor. low pressure compressor.
What should be done initially if a turbine engine catches fire when starting? Turn off the fuel and continue engine rotation with the starter. Continue engine start rotation and discharge a fire extinguisher into the intake. Continue starting attempt in order to blow out the fire.
What is the proper starting sequence for a turbojet engine? Ignition, starter, fuel. Starter, ignition, fuel. Starter, fuel, ignition.
A weak fuel to air mixture along with normal airflow through a turbine engine may result in a rich flameout. a lean die-out. high EGT.
What is used in turbine engines to aid in stabilization of compressor airflow during low thrust engine operation? Stator vanes and rotor vanes. Variable guide vanes and/or compressor bleed valves. Pressurization and dump valves.
In a turbine engine with a dual-spool compressor, the low speed compressor always turns at the same speed as the high speed compressor. is connected directly to the high speed compressor. seeks its own best operating speed.
What is the function of the inlet guide vane assembly on an axial-flow compressor? Directs the air into the first stage rotor blades at the proper angle. Converts velocity energy into pressure energy. Converts pressure energy into velocity energy.
Which of the following is a good indication of a malfunctioning fuel nozzle when inspecting the exhaust section of an aircraft turbine engine? Buckling of the combustion liner. Hotspots on the tail cone. Carbon build up in the exhaust.
The stator vanes in an axial-flow compressor convert velocity energy into pressure energy. convert pressure energy into velocity energy. direct air into the first stage rotor vanes at the proper angle.
The velocity of subsonic air as it flows through a convergent nozzle increases. decreases. remains constant.
The velocity of supersonic air as it flows through a divergent nozzle increases. decreases. is inversely proportional to the temperature.
The pressure of subsonic air as it flows through a convergent nozzle increases. decreases. remains constant.
The pressure of supersonic air as it flows through a divergent nozzle increases. decreases. is inversely proportional to the temperature.
Anti-icing of jet engine air inlets is commonly accomplished by electrical heating elements inside the inlet guide vanes. engine bleed air ducted through the critical areas. electrical heating elements located within the engine air inlet cowling.
Generally, when starting a turbine engine, the starter should be disengaged after the engine has reached self-accelerating speed. only after the engine has reached full idle RPM. when the ignition and fuel system are activated.
What is the primary advantage of an axial-flow compressor over a centrifugal compressor? High frontal area. Less expensive. Greater pressure ratio.
The purpose of a bleed valve, located in the beginning stages of the compressor, in an aircraft gas turbine engine is to vent some of the air overboard to prevent a compressor stall. control excessively high RPM to prevent a compressor stall. vent high ram air pressure overboard to prevent a compressor stall.
What is meant by a double entry centrifugal compressor? A compressor that has two intakes. A two-stage compressor independently connected to the main shaft. A compressor with vanes on both sides of the impeller.
What is the major function of the turbine assembly in a turbojet engine? Directs the gases in the proper direction to the tailpipe. Supplies the power to turn the compressor. Increases the temperature of the exhaust gases.
Stator blades in the compressor section of an axial-flow turbine engine increase the air velocity and prevent swirling. straighten the airflow and accelerate it. decrease the air velocity and prevent swirling.
A gas turbine engine comprises which three main sections? Compressor, diffuser, and stator. Turbine, combustion, and stator. Turbine, compressor, and combustion.
What type of turbine blade is most commonly used in aircraft jet engines? Reaction. Impulse. Impulse-reaction.
What is the primary factor which controls the pressure ratio of an axial-flow compressor? Number of stages in compressor. Compressor inlet pressure. Compressor inlet temperature.
The non-rotating axial-flow compressor airfoils in an aircraft gas turbine engine, are called rotor blades. stator vanes. disc rims.
(1) In a turbine engine axial-flow compressor, each consecutive pair of rotor and stator blades constitutes a pressure stage.
(2) In a turbine engine axial-flow compressor, the number of rows of stages is determined by the amount of air and total pressure rise required.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
The air passing through the combustion chamber of a turbine engine is used to support combustion and to cool the engine. entirely combined with fuel and burned. speeded up and heated by the action of the turbines.
The stators in the turbine section of a gas turbine engine increase the velocity of the gas flow. decrease the velocity of the gas flow. increase the pressure of the gas flow.
The compressor stators in a gas turbine engine act as diffusers to decrease the velocity of the gas flow. increase the velocity of the gas flow. increase the velocity and decrease the pressure of the gas.
The procedure for removing the accumulation of dirt deposits on compressor blades is called the soak method. field cleaning. the purging process.
Which of the following may be used to accomplish internal inspection of an assembled turbine engine?
1. Infrared photography.
3. A borescope.
4. Fluorescent penetrant and ultraviolet light. 1, 2, 3. 1, 3. 3.
What is the possible cause when a turbine engine indicates no change in power setting parameters, but oil temperature is high? High scavenge pump oil flow. Engine main bearing distress. Turbine damage and/or loss of turbine efficiency.
Newton's First Law of Motion, generally termed the Law of Inertia, states: To every action there is an equal and opposite reaction. Force is proportional to the product of mass and acceleration. Every body persists in its state of rest, or of motion in a straight line, unless acted upon by some outside force.
A turbine engine hot section is particularly susceptible to which kind of damage? Erosion. Cracking. Elongation.
Dirt particles in the air being introduced into the compressor of a turbine engine will form a coating on all but which of the following? Turbine blades. Casings. Inlet guide vanes.
Severe rubbing of turbine engine compressor blades will usually cause bowing. cracking. galling.
Which of the following influences the operation of an automatic fuel control unit on a turbojet engine? Burner pressure. Mixture control position. Exhaust gas temperature.
If a turbine engine is unable to reach takeoff EPR before its EGT limit is reached, this is an indication that the fuel control must be replaced. EGT controller is out of adjustment. compressor may be contaminated or damaged.
The Brayton cycle is known as the constant pressure cycle. temperature cycle. mass cycle.
Continued and/or excessive heat and centrifugal force on turbine engine rotor blades is likely to cause profile. creep. galling.
If the RPM of an axial-flow compressor remains constant, the angle of attack of the rotor blades can be changed by changing the velocity of the airflow. changing the compressor diameter. increasing the pressure ratio.
The compression ratio of an axial-flow compressor is a function of the number of compressor stages. rotor diameter. air inlet velocity.
Which of the following variables affect the inlet air density of a turbine engine?
1. Speed of the aircraft.
2. Compression ratio.
3. Turbine inlet temperature.
4. Altitude of the aircraft.
5. Ambient temperature.
6. Turbine and compressor efficiency. 1, 3, 6. 1, 4, 5. 4, 5, 6.
Which of the following factors affect the thermal efficiency of a turbine engine?
1. Turbine inlet temperature.
2. Compression ratio.
3. Ambient temperature.
4. Speed of the aircraft.
5. Turbine and compressor efficiency.
6. Altitude of the aircraft. 3, 4, 6. 1, 2, 5. 1, 2, 6.
Why do some turbine engines have more than one turbine wheel attached to a single shaft? To facilitate balancing of the turbine assembly. To help stabilize the pressure between the compressor and the turbine. To extract more power from the exhaust gases than a single wheel can absorb.
The exhaust section of a turbine engine is designed to impart a high exit velocity to the exhaust gases. increase temperature, therefore increasing velocity. decrease temperature, therefore decreasing pressure.
Which of the following types of combustion sections are used in aircraft turbine engines? Annular, variable, and cascade vane. Can, multiple-can, and variable. Multiple-can, annular, and can-annular.
A cool-off period prior to shutdown of a turbine engine is accomplished in order to allow the turbine wheel to cool before the case contracts around it. prevent vapor lock in the fuel control and/or fuel lines. prevent seizure of the engine bearings.
What type igniter plug is used in the low tension ignition system of an aircraft turbofan engine? Low voltage, high amperage glow plug. Self-ionizing or shunted-gap type plug. Recessed surface gap plug.
What is meant by a shrouded turbine? The turbine blades are shaped so that their ends form a band or shroud. The turbine wheel is enclosed by a protective shroud to contain the blades in case of failure. The turbine wheel has a shroud or duct which provides cooling air to the turbine blades.
What term is used to describe a permanent and cumulative deformation of the turbine blades of a turbojet engine? Stretch. Distortion. Creep.
What is the purpose of the dump valve used on aircraft gas turbine engines? The fuel is quickly cut off to the nozzles and the manifolds are drained preventing fuel boiling off as a result of residual engine heat. The valve controls compressor stall by dumping compressor bleed air from the compressor discharge port under certain conditions. Maintains minimum fuel pressure to the engine fuel control unit inlet and dumps excessive fuel back to the inlet of the engine-driven fuel pump.
At what stage in a turbine engine are gas pressures the greatest? Compressor inlet. Turbine outlet. Compressor outlet.
In what section of a turbojet engine is the jet nozzle located? Combustion. Turbine. Exhaust.
(1) Accumulation of contaminates in the compressor of a turbojet engine reduces aerodynamic efficiency of the blades.
(2) Two common methods for removing dirt deposits from turbojet engine compressor blades are a fluid wash and an abrasive grit blast.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Hot spots in the combustion section of a turbojet engine are possible indicators of faulty igniter plugs. dirty compressor blades. malfunctioning fuel nozzles.
Which of the following can cause fan blade shingling in a turbofan engine?
1. Engine overspeed.
2. Engine overtemperature.
3. Large, rapid throttle movements.
4. FOD. 1, 2. 1, 2, 3, 4. 1, 4.
Compressor stall is caused by a low angle of attack airflow through the first stages of compression. a high angle of attack airflow through the first stages of compression. rapid engine deceleration.
A condition known as 'hot streaking' in turbine engines is caused by a partially clogged fuel nozzle. a misaligned combustion liner. excessive fuel flow.
Newton's Law of Motion, generally termed the "Law of Momentum," states: Acceleration is produced when a force acts on a mass. The greater the mass, the greater the amount of force needed. For every action there is an equal and opposite reaction. Every body persists in its state of rest, or of motion in a straight line, unless acted upon by some outside force.
Which of the following acts as a diffuser in a turbine engine and converts velocity to pressure? Impeller. Manifold. Stators.
Determine which portion of the AD is applicable for Model O-690 series engine, serial No. 5863-40 with 283 hours' time in service.
This is the compliance portion of an FAA Airworthiness Directive.
Compliance required as indicated:
(A) For model O-690 series engines, serial Nos. 101-40 through 5264-40 and IO-690 series engines, serial Nos. 101-48 through 423-48, compliance with (C) required within 25 hours' time in service after the effective date of this AD and every 100 hours' time in service thereafter.
(B) For Model O-690 series engines, serial Nos. 5265-40 through 6129-40 and IO-690 series engines, serial Nos. 424-48 through 551-48, compliance with (C) required as follows:
(1) Within 25 hours' time in service after the effective date of this AD and every 100 hours' time in service thereafter for engines with more than 275 hours' time in service on the effective date of this AD.
(2) Prior to the accumulation of 300 hours total time in service and every 100 hours' time in service thereafter for engines with 275 hours or less time in service on the effective date of this AD.
(C) Inspect the oil pump drive shaft (P/N 67512) on applicable engines in accordance with instructions contained in Connin Service Bulletin No. 295. Any shafts which are found to be damaged shall be replaced before further flight. These inspections shall be continued until Connin P/N 67512 (redesigned) or P/N 74641 oil pump drive shaft is installed at which time the inspections may be discontinued. (B), (1). (A). (B), (2).
A Cessna 180 aircraft has a McCauley propeller Model No. 2A34C50/90A. The propeller is severely damaged in a ground accident, and this model propeller is not available for replacement. Which of the following should be used to find an approved alternate replacement? Summary of Supplemental Type Certificates. Aircraft Specifications/Type Certificate Data Sheets. Aircraft Engine and Propeller Specifications/Type Certificate Data Sheets.
Which of the following is used to monitor the mechanical integrity of the turbines, as well as to check engine operating conditions of a turbine engine? Engine oil pressure. Exhaust gas temperature. Engine pressure ratio.
On a reciprocating engine aircraft using a shrouded exhaust muffler system as a source for cabin heat, the exhaust system should be visually inspected for any indication of cracks or an operational carbon monoxide detection test should be done. replaced at each reciprocating engine overhaul by a new or overhauled exhaust system or an hydrostatic test should be accomplished. removed and the exhaust muffler checked for cracks by using magnetic particle inspection method or an hydrostatic test should be done on the exhaust muffler.
(1) Airworthiness Directives are Federal Aviation Regulations and must be complied with unless specific exemption is granted.
(2) Airworthiness Directives of an emergency nature may require immediate compliance upon receipt.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Which of the following contains a minimum checklist for 100-hour inspections of engines? 14 CFR Part 33 Appendix A. 14 CFR Part 43 Appendix D. Engine Specifications or Type Certificate Data Sheets.
When must an Airworthiness Directive (AD) be complied with after it becomes effective? As specified in the AD. During the next scheduled inspection. At the next scheduled overhaul.
Which of the following contains a table that lists the engines to which a given propeller is adaptable? Aircraft Type Certificate Data Sheets. Propeller Type Certificate Data Sheets. Engine Type Certificate Data Sheets.
Which of the following component inspections is to be accomplished on a 100-hour inspection? Check internal timing of magneto. Check cylinder compression. Check valve timing.
You are performing a 100-hour inspection on an R985-22 aircraft engine. What does the '985' indicate? The total piston displacement of the engine. The pistons will pump a maximum of 985 cubic inches of air per crankshaft revolution. The total piston displacement of one cylinder.
Where would one find type design information for an R1830-92 engine certificated under the Civil Air Regulations (CAR) and installed on a DC-3? The Aircraft Specifications and Type Certificate Data Sheet. The Aircraft Engine Specifications. The Aircraft Engine Type Certificate Handbook.
Straightening nitrided crankshafts is recommended. not recommended. approved by the manufacturer.
The breaking loose of small pieces of metal from coated surfaces, usually caused by defective plating or excessive loads, is called flaking. chafing. brinelling.
Each powerplant installed on an airplane with a Standard Airworthiness Certificate must have been type certificated. manufactured under the TSO system. originally certificated for that aircraft.
A severe condition of chafing or fretting in which a transfer of metal from one part to another occurs is called scoring. burning. galling.
Indentations on bearing races caused by high static loads are known as fretting. brinelling. galling.
When inspecting an aircraft reciprocating engine what document is used to determine if the proper magnetos are installed? Instruction for continued airworthiness issued by the engine manufacturer. Engine Manufacturer's Maintenance Manual. Aircraft Engine Specifications or Type Certificate Data Sheets.
Which of the following can inspect and approve an engine major repair for return to service? Certificated mechanic with airframe and powerplant ratings. Certificated mechanic with a powerplant rating. Certificated mechanic with inspection authorization.
What publication is used for guidance to determine whether a powerplant repair is major or minor? Airworthiness Directives. 14 CFR part 43. Aircraft owner's manual.
The airworthiness standards for the issue of type certificates for small airplanes with nine or less passenger seats in the normal, utility, and acrobatic categories may be found in the Federal Aviation Regulations, Part 23. Supplemental Type Certificate. Federal Aviation Regulations, Part 21.
Which of the following contains approved data for performing a major repair to an aircraft engine? Engine Type Certificate Data Sheets. Supplemental Type Certificates. Manufacturer's maintenance instructions when FAA approved.
What maintenance record(s) is/are required following a major repair of an aircraft engine? Entries in engine maintenance records and a list of discrepancies for the FAA. Entries in the engine maintenance record and FAA Form 337. Entry in logbook.
A ground incident that results in propeller sudden stoppage would require a crankshaft runout inspection. What publication would be used to obtain crankshaft runout tolerance? Current manufacturer's maintenance instructions. Type Certificate Data Sheet. AC 43.13-1A, Acceptable Methods, Techniques, and Practices -- Aircraft Inspection and Repair.
Select the Airworthiness Directive applicability statement which applies to an IVO-355 engine, serial number T8164, with 2,100 hours' total time and 300 hours since rebuilding. Applies to all IVO-355 engines, serial numbers T8000 through T8300, having less than 2,400 hours' total time. Applies to all IVO-355 engines, serial numbers T8000 through T8900 with 2,400 hours or more total time. Applies to all I.O. and TV10-355 engines, all serial numbers regardless of total time or since overhaul.
What publication contains the mandatory replacement time for parts of a turbine engine? Engine Manufacturer's service instructions. Federal Aviation Regulation Part 43. Engine Manufacturer's maintenance manual.
How is the flow range of the fuel discharge nozzles installed in a fuel injected reciprocating engine indicated? By a letter stamped on the hex of the nozzle body. By a number stamped on the hex of the nozzle body. By the code located on the engine data plate.
What section in the instructions for continued airworthiness is FAA approved? Engine maintenance manual or section. Engine overhaul manual or section. Airworthiness limitations section.
Which of the following conditions is usually not acceptable to any extent in turbine blades? Cracks. Pits. Dents.
(1) Serviceability limits for turbine blades are much more stringent than are those for turbine nozzle vanes.
(2) A limited number of small nicks and dents can usually be permitted in any area of a turbine blade.
Regarding the above statements, both No. 1 and No. 2 are true. neither No. 1 nor No. 2 is true. only No. 1 is true.
Which unit most accurately indicates fuel consumption of a reciprocating engine? Fuel flowmeter. Fuel pressure gauge. Electronic fuel quantity indicator.
The fuel flowmeter used with a continuous-fuel injection system installed on an aircraft horizontally opposed reciprocating engines measures the fuel pressure drop across the manifold valve. fuel nozzles. metering valve.
The principle fault in the pressure type fuel flowmeter indicating system, installed on a horizontally opposed continuous-flow fuel injected aircraft reciprocating engine, is that a plugged fuel injection nozzle will cause a normal operation indication. lower than normal fuel flow indication. higher than normal fuel flow indication.
Motor driven impeller and turbine fuel flow transmitters are designed to transmit data using aircraft electrical system power. mechanically. by fuel pressure.
The fuel-flow indicator rotor and needle for a motor-impeller and turbine indicating system is driven by an electrical signal. direct coupling to the motor shaft. a mechanical gear train.
On a twin-engine aircraft with fuel-injected reciprocating engines, one fuel-flow indicator reads considerably higher than the other in all engine operating configurations. What is the probable cause of this indication? Carburetor icing. One or more fuel nozzles are clogged. Alternate air door stuck open.
The fuel-flow indication system used with many fuel-injected opposed engine airplanes utilizes a measure of fuel flow volume. fuel pressure. fuel flow mass.
In addition to fuel quantity, a computerized fuel system (CFS) with a totalizer-indicator provides indication of how many of the following?
1. Fuel flow rate.
2. Fuel used since reset or initial start-up.
3. Fuel time remaining at current power setting.
4. Fuel temperature. Two. Three. Four.
The fuel-flow indication data sent from motor driven impeller and turbine, and motorless type fuel flow transmitters is a measure of fuel mass-flow. fuel volume-flow. engine burner pressure drop.
In an aircraft equipped with a pressure-drop type fuel-flow indicating system, if one of the injector nozzles becomes restricted, this would cause a decrease in fuel flow with a decreased fuel flow indication on the gauge. an increased fuel flow indication on the gauge. no change in fuel flow indication on the gauge.
A manifold pressure gauge is designed to maintain constant pressure in the intake manifold. indicate differential pressure between the intake manifold and atmospheric pressure. indicate absolute pressure in the intake manifold.
The purpose of an exhaust gas analyzer is to indicate the brake specific fuel consumption. fuel/air ratio being burned in the cylinders. temperature of the exhaust gases in the exhaust manifold.
Which of the following types of electric motors are commonly used in electric tachometers? Direct current, series-wound motors. Synchronous motors. Direct current, shunt-wound motors.
Where are the hot and cold junctions located in an engine cylinder temperature indicating system? Both junctions are located at the instrument. Both junctions are located at the cylinder. The hot junction is located at the cylinder and the cold junction is located at the instrument.
Basically, the indicator of a tachometer system is responsive to change in current flow. frequency. voltage.
Which statement is correct concerning a thermocouple-type temperature indicating instrument system? It is a balanced-type, variable resistor circuit. It requires no external power source. It usually contains a balancing circuit in the instrument case to prevent fluctuations of the system voltage from affecting the temperature reading.
Which statement is true regarding a thermocouple-type cylinder head temperature measuring system? The resistance required for cylinder head temperature indicators is measured in farads. The voltage output of a thermocouple system is determined by the temperature difference between the two ends of the thermocouple. When the master switch is turned on, a thermocouple indicator will move off-scale to the low side.
What basic meter is used to indicate cylinder head temperature in most aircraft? Electrodynamometer. Galvanometer. Thermocouple-type meter.
Which of the following is a primary engine instrument? Tachometer. Fuel flowmeter. Airspeed indicator.
A complete break in the line between the manifold pressure gauge and the induction system will be indicated by the gauge registering prevailing atmospheric pressure. zero. lower than normal for conditions prevailing.
Engine oil temperature gauges indicate the temperature of the oil entering the oil cooler. entering the engine. in the oil storage tank.
Why do helicopters require a minimum of two synchronous tachometer systems? One indicates engine RPM and the other tail rotor RPM. One indicates main rotor RPM and the other tail rotor RPM. One indicates engine RPM and the other main rotor RPM.
If the thermocouple leads were inadvertently crossed at installation, what would the cylinder temperature gauge pointer indicate? Normal temperature for prevailing condition. Moves off-scale on the zero side of the meter. Moves off-scale on the high side of the meter.
A common type of electrically operated oil temperature gauge utilizes either a wheatstone bridge or ratiometer circuit. a thermocouple type circuit. vapor pressure and pressure switches.
The indication on a thermocouple-type cylinder head temperature indicator is produced by resistance changes in two dissimilar metals. a difference in the voltage between two dissimilar metals. a current generated by the temperature difference between dissimilar metal hot and cold junctions.
(1) Powerplant instrument range markings show whether the current state of powerplant operation is normal, acceptable for a limited time, or unauthorized.
(2) Powerplant instrument range markings are based on installed engine operating limits which may not exceed (but are not necessarily equal to) those limits shown on the engine Type Certificate Data Sheet.
Regarding the above statements, both No. 1 and No. 2 are true. neither No. 1 nor No. 2 is true. only No. 1 is true.
Thermocouple leads may be installed with either lead to either post of the indicator. are designed for a specific installation and may not be altered. may be repaired using solderless connectors.
(1) Engine pressure ratio (EPR) is a ratio of the exhaust gas pressure to the engine inlet air pressure, and indicates the thrust produced.
(2) Engine pressure ratio (EPR) is a ratio of the exhaust gas pressure to the engine inlet air pressure, and indicates volumetric efficiency.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
What unit in a tachometer system sends information to the indicator? The three-phase ac generator. The two-phase ac generator. The synchronous motor.
(1) Generally, when a turbine engine indicates high EGT for a particular EPR (when there is no significant damage), it means that the engine is out of trim.
(2) Some turbine-powered aircraft use RPM as the primary indicator of thrust produced, others use EPR as the primary indicator.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Engine pressure ratio is determined by multiplying engine inlet total pressure by turbine outlet total pressure. dividing turbine outlet total pressure by engine inlet total pressure. dividing engine inlet total pressure by turbine outlet total pressure.
Turbine engine EGT thermocouples are constructed of iron and constantan. copper and constantan. chromel and alumel.
Which of the following instrument discrepancies require replacement of the instrument?
1. Red line missing from glass.
2. Glass cracked.
3. Case paint chipped.
4. Will not zero out.
5. Pointer loose on shaft.
6. Mounting screw loose.
7. Leaking at line B nut.
8. Fogged. 2, 3, 7, 8. 2, 4, 5, 8. 1, 2, 4, 7.
A Bourdon-tube instrument may be used to indicate
4. quantity. 1 and 2. 1 and 3. 2 and 4.
An indication of unregulated power changes that result in continual drift of manifold pressure indication on a turbosupercharged aircraft engine is known as Overshoot. Waste gate fluctuation. Bootstrapping.
Which of the following instrument conditions is acceptable and does not require immediate correction? Case paint chipped. Instrument glass fogged. Mounting screws loose.
A change in engine manifold pressure has a direct effect on the piston displacement. compression ratio. mean effective cylinder pressure.
What instrument on a gas turbine engine should be monitored to minimize the possibility of a 'hot' start? RPM indicator. Turbine inlet temperature. Torquemeter.
In regard to using a turbine engine oil analysis program, which of the following is NOT true? Generally, an accurate trend forecast may be made after an engine's first oil sample analysis. It is best to start an oil analysis program on an engine when it is new. A successful oil analysis program should be run over an engine's total operating life so that normal trends can be established.
On an aircraft turbine engine, operating at a constant power, the application of engine anti-icing will result in noticeable shift in EPR. a false EPR reading. an increase in EPR.
Engine pressure ratio is the total pressure ratio between the aft end of the compressor and the aft end of the turbine. front of the compressor and the rear of the turbine. front of the engine inlet and the aft end of the compressor.
What would be the possible cause if a gas turbine engine has high exhaust gas temperature, high fuel flow, and low RPM at all engine power settings? Fuel control out of adjustment. Loose or corroded thermocouple probes for the EGT indicator. Turbine damage or loss of turbine efficiency.
What is the primary purpose of the tachometer on an axial-compressor turbine engine? Monitor engine RPM during cruise conditions. It is the most accurate instrument for establishing thrust settings under all conditions. Monitor engine RPM during starting and to indicate overspeed conditions.
The engine pressure ratio (EPR) indicator is a direct indication of engine thrust being produced. pressure ratio between the front and aft end of the compressor. ratio of engine RPM to compressor pressure.
The exhaust gas temperature (EGT) indicator on a gas turbine engine provides a relative indication of the exhaust temperature. temperature of the exhaust gases as they pass the exhaust cone. turbine inlet temperature.
What instrument indicates the thrust of a gas turbine engine? Exhaust gas temperature indicator. Turbine inlet temperature indicator. Engine pressure ratio indicator.
In a turbine engine, where is the turbine discharge pressure indicator sensor located? At the aft end of the compressor section. At a location in the exhaust cone that is determined to be subjected to the highest pressures. Immediately aft of the last turbine stage.
In what units are turbine engine tachometers calibrated? Percent of engine RPM. Actual engine RPM. Percent of engine pressure ratio.
Instruments that provide readings of low or negative pressure, such as manifold pressure gauges, are usually what type? Vane with calibrated spring. Bourdon tube. Diaphragm or bellows.
Instruments that measure relatively high fluid pressures, such as oil pressure gauges, are usually what type? Vane with calibrated spring. Bourdon tube. Diaphragm or bellows.
The RPM indication of a synchronous ac motor-tachometer is governed by the generator voltage. current. frequency.
The EGT gauge used with reciprocating engines is primarily used to furnish temperature readings in order to obtain the best mixture setting for fuel efficiency. obtain the best mixture setting for engine cooling. prevent engine overtemperature.
A red triangle, dot, or diamond mark on an engine instrument face or glass indicates the maximum operating limit for all normal operations. the maximum limit for high transients such as starting. a restricted operating range.
The thermocouple leads used to measure cylinder temperature on an aircraft reciprocating engine should be cut and trimmed to fit if the lead is too long. are connected to the electrical wiring on one end and the cylinder on the other end. connected to the cylinder can only be bayonet type.
Which of the following fire detection systems are commonly used in an engine nacelle? Fire detection control unit. Thermocouple detector. Kidde continuous-loop.
What is the function of a fire detection system? To discharge the powerplant fire-extinguishing system at the origin of the fire. To activate a warning device in the event of a powerplant fire. To identify the location of a powerplant fire.
(Refer to Figure 2.) Determine the fire-extinguisher container pressure limits when the temperature is 75°F. 326 minimum and 415 maximum. 330 minimum and 419 maximum. 338 minimum and 424 maximum.
How are most aircraft turbine engine fire-extinguishing systems activated? Electrically discharged cartridges. Manual remote control valve. Pushrod assembly.
How does carbon dioxide (CO(2)) extinguish an aircraft engine fire? Contact with the air converts the liquid into snow and gas which smothers the flame. By lowering the temperature to a point where combustion will not take place. The high pressure spray lowers the temperature and blows out the fire.
What retains the nitrogen charge and fire-extinguishing agent in a high rate of discharge (HRD) container? Breakable disk and fusible disk. Pressure switch and check tee valve. Pressure gauge and cartridge.
A continuous-loop fire detector is what type of detector? Spot detector. Overheat detector. Rate-of-temperature-rise detector.
What is the operating principle of the spot detector sensor in a fire detection system? Resistant core material that prevents current flow at normal temperatures. A conventional thermocouple that produces a current flow. A bimetallic thermoswitch that closes when heated to a high temperature.
How is the fire-extinguishing agent distributed in the engine section? Spray nozzles and fluid pumps. Nitrogen pressure and slinger rings. Spray nozzles and perforated tubing.
Which of the following is the safest fire-extinguishing agent to use from a standpoint of toxicity and corrosion hazards? Dibromodifluoromethane (Halon 1202). Bromochlorodifluoromethane (Halon 1211). Bromotrifluoromethane (Halon 1301).
Which of the following is NOT used to detect fires in reciprocating engine nacelles? Smoke detectors. Rate-of-temperature-rise detectors. Flame detectors.
What is the principle of operation of the continuous-loop fire detector system sensor? Fuse material which melts at high temperatures. Core resistance material which prevents current flow at normal temperatures. A bimetallic thermoswitch which closes when heated to a high temperature.
The most satisfactory extinguishing agent for a tailpipe or intake fire is carbon dioxide. dry chemical. methyl bromide.
The explosive cartridge in the discharge valve of a fire-extinguisher container is a life-dated unit. not a life-dated unit. mechanically fired.
Why does one type of Fenwal fire detection system use spot detectors wired in parallel between two separate circuits? To provide an installation that is equal to two separate systems: a primary system and a secondary, or back-up system. So that a double fault may exist in the system without sounding a false alarm. So that a single fault may exist in the system without sounding a false alarm.
Which of the following fire detection systems measures temperature rise compared to a reference temperature? Thermocouple. Thermal switch. Lindberg continuous element.
The pulling out (or down) of an illuminated fire handle in a typical large jet aircraft fire protection system commonly accomplishes what events? Closes all firewall shutoff valves, disconnects the generator, and discharges a fire bottle. Closes fuel shutoff, closes hydraulic shutoff, disconnects the generator field, and arms the fire-extinguishing system. Closes fuel shutoff, closes hydraulic shutoff, closes the oxygen shutoff, disconnects the generator field, and arms the fire-extinguishing system.
A fire detection system operates on the principle of a buildup of gas pressure within a tube proportional to temperature. Which of the following systems does this statement define? Kidde continuous-loop system. Lindberg continuous-element system. Thermal switch system.
The fire detection system that uses a single wire surrounded by a continuous string of ceramic beads in a tube is the Fenwal system. Kidde system. thermocouple system.
The fire detection system that uses two wires imbedded in a ceramic core within a tube is the Fenwal system. Lindberg system. Kidde system.
A fuel or oil fire is defined as a class B fire. class A fire. class C fire.
A fire detection system that operates on the rate-of-temperature rise is a continuous-loop system. thermocouple system. thermal switch system.
A fire involving energized electrical equipment is defined as a class B fire. class D fire. class C fire.
Two continuous-loop fire detection systems that will not test due to a broken detector element are the Kidde system and the Lindberg system. Kidde system and the Fenwal system. thermocouple system and the Lindberg system.
Which statement best describes the blowout type indicator disk on a fixed fire extinguishing system? When the red indicator disk is missing, it indicates the fire extinguishing system is charged and ready for use. When the yellow indicator disk is missing, it indicates the fire extinguishing system has been normally discharged. When the green indicator disk is missing, it indicates that the fire extinguishing system may have been normally discharged.
The most satisfactory extinguishing agent for an electrical fire is carbon tetrachloride. carbon dioxide. methyl bromide.
Which of the following fire detection systems will detect a fire when an element is inoperative but will not test when the test circuit is energized? The Kidde system and the thermocouple system. The Kidde system and the Fenwal system. The thermocouple system and the Lindberg system.
Which of the following fire detection systems uses heat in the normal testing of the system? The thermocouple system and the Lindberg system. The Kidde system and the Fenwal system. The thermocouple system and the Fenwal system.
After a fire is extinguished, or overheat condition removed in aircraft equipped with a Systron-Donner fire detector, the detection system must be manually reset. automatically resets. sensing component must be replaced.
The use of water on class D fires is most effective if sprayed in a fine mist. will cause the fire to burn more violently and can cause explosions. has no effect.
For fire detection and extinguishing purposes, aircraft powerplant areas are divided into fire zones based on hot and cold sections of the engine. the volume and smoothness of the airflow through engine compartments. engine type and size.
(Refer to Figure 3.) What are the fire-extinguisher container pressure limits when the temperature is 50°F? 425 - 575 PSIG. 435 - 605 PSIG. 475 - 625 PSIG.
What device is used to convert alternating current, which has been induced into the loops of the rotating armature of a dc generator, to direct current? A rectifier. A commutator. An inverter.
A certain direct current series motor mounted within an aircraft draws more amperes during start than when it is running under its rated load. The most logical conclusion that may be drawn is the starting winding is shorted. the brushes are floating at operating RPM because of weak brush springs. the condition is normal for this type of motor.
The stationary field strength in a direct current generator is varied by the reverse-current relay. because of generator speed. according to the load requirements.
What type of electric motor is generally used with a direct-cranking engine starter? Direct current, shunt-wound motor. Direct current, series-wound motor. Synchronous motor.
Upon what does the output frequency of an ac generator (alternator) depend? The speed of rotation and the strength of the field. The speed of rotation, the strength of the field, and the number of field poles. The speed of rotation and the number of field poles.
A high surge of current is required when a dc electric motor is first started. As the speed of the motor increases, the counter emf decreases proportionally. the applied emf increases proportionally. the counter emf builds up and opposes the applied emf, thus reducing the current flow through the armature.
Alternators (ac generators) that are driven by a constant-speed drive (CSD) mechanism are used to regulate the alternator to a constant voltage output. amperage output. hertz output.
What is used to polish commutators or slip rings? Double-0 sandpaper. Stiff bristle brushes. Emery cloths.
If a generator is malfunctioning, its voltage can be reduced to residual by actuating the rheostat. generator master switch. master solenoid.
If the points in a vibrator-type voltage regulator stick in the closed position while the generator is operating, what will be the probable result? Generator output voltage will decrease. Generator output voltage will not be affected. Generator output voltage will increase.
Why is a constant-speed drive used to control the speed of some aircraft engine-driven generators? So that the voltage output of the generator will remain within limits. To eliminate uncontrolled surges of current to the electrical system. So that the frequency of the alternating current output will remain constant.
According to the electron theory of the flow of electricity, when a properly functioning dc alternator and voltage regulating system is charging an aircraft's battery, the direction of current flow through the battery is into the negative terminal and out the positive terminal. is into the positive terminal and out the negative terminal. cycles back and forth with the number of cycles per second being controlled by the rotational speed of the alternator.
Aircraft that operate more than one generator connected to a common electrical system must be provided with automatic generator switches that operate to isolate any generator whose output is less than 80 percent of its share of the load. an automatic device that will isolate nonessential loads from the system if one of the generators fails. individual generator switches that can be operated from the cockpit during flight.
The most effective method of regulating aircraft direct current generator output is to vary, according to the load requirements, the strength of the stationary field. generator speed. number of rotating armature loops in use.
Electric motors are often classified according to the method of connecting the field coils and armature. Aircraft engine starter motors are generally of which type? Compound. Series. Shunt (parallel).
As the generator load is increased (within its rated capacity), the voltage will decrease and the amperage output will increase. remain constant and the amperage output will increase. remain constant and the amperage output will decrease.
As the flux density in the field of a dc generator increases and the current flow to the system increases, the generator voltage decreases. generator amperage decreases. force required to turn the generator increases.
What is the purpose of a reverse-current cutout relay? It eliminates the possibility of reversed polarity of the generator output current. It prevents fluctuations of generator voltage. It opens the main generator circuit whenever the generator voltage drops below the battery voltage.
Generator voltage will not build up when the field is flashed and solder is found on the brush cover plate. These are most likely indications of an open armature. excessive brush arcing. armature shaft bearings overheating.
Why is it unnecessary to flash the field of the exciter on a brushless alternator? The exciter is constantly charged by battery voltage. Brushless alternators do not have exciters. Permanent magnets are installed in the main field poles.
One way that the automatic ignition relight systems are activated on gas turbine engines is by a drop in compressor discharge pressure. sensing switch located in the tailpipe. drop in fuel flow.
How are the rotor windings of an aircraft alternator usually excited? By a constant ac voltage from the battery. By a constant ac voltage. By a variable direct current.
What precaution is usually taken to prevent electrolyte from freezing in a lead acid battery? Place the aircraft in a hangar. Remove the battery and keep it under constant charge. Keep the battery fully charged.
What is the ampere-hour rating of a storage battery that is designed to deliver 45 amperes for 2.5 hours? 112.5 ampere-hour. 90.0 ampere-hour. 45.0 ampere-hour.
How many hours will a 140 ampere-hour battery deliver 15 amperes? 1.40 hours. 9.33 hours. 14.0 hours.
What is a basic advantage of using ac for electrical power for a large aircraft? AC systems operate at higher voltage than dc systems and therefore use less current and can use smaller and lighter weight wiring. AC systems operate at lower voltage than dc systems and therefore use less current and can use smaller and lighter weight wiring. AC systems operate at higher voltage than dc systems and therefore use more current and can use smaller and lighter weight wiring.
What are two types of ac motors that are used to produce a relatively high torque? Shaded pole and shunt field. Shunt field and single phase. Three-phase induction and capacitor start.
(1) Alternators are rated in volt-amps, which is a measure of the apparent power being produced by the generator.
(2) Alternating current has the advantage over direct current in that its voltage and current can easily be stepped up or down.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
What is the frequency of most aircraft alternating current? 115 Hertz. 60 Hertz. 400 Hertz.
The reason for flashing the field in a generator is to restore residual magnetism to the field frame. ensure proper operation of the capacitor. relieve the unit of any residual electrical energy.
The part of a dc alternator power system that prevents reverse flow of current from the battery to the alternator is the reverse current relay. voltage regulator. rectifier.
The generating system of an aircraft charges the battery by using constant current and varying voltage. constant voltage and varying current. constant voltage and constant current.
The constant current method of charging a ni-cad battery will bring it up to fully charged in the shortest amount of time. will lead to cell imbalance over a period of time. is the method most effective in maintaining cell balance.
(Refer to Figure 4.) The following data concerning the installation of an electrical unit is known: current requirements for continuous operation -- 11 amperes; measured cable length -- 45 feet; system voltage -- 28 volts (do not exceed 1 volt drop); cable in conduit and bundles. What is the minimum size copper electrical cable that may be selected? No. 10. No. 12. No. 14.
Which of the following aircraft circuits does NOT contain a fuse/circuit breaker? Generator circuit. Air-conditioning circuit. Starter circuit.
The maximum number of terminals that may be connected to any one terminal stud in an aircraft electrical system is two. three. four.
What is the maximum number of bonding jumper wires that may be attached to one terminal grounded to a flat surface? Two. Three. Four.
Starter brushes should be replaced when they are worn down to one-half of the original length. three-quarters of the original length. one-quarter of the original length.
When installing an electrical switch, under which of the following conditions should the switch be derated from its nominal current rating? Conductive circuits. Capacitive circuits. Direct-current motor circuits.
The resistance of the current return path through the aircraft is always considered negligible, provided the voltage drop across the circuit is checked. generator is properly grounded. structure is adequately bonded.
In order to reduce the possibility of ground shorting the circuits when the connectors are separated for maintenance, the AN and MS electrical connectors should be installed with the socket section on the ground side of the electrical circuit. pin section on the ground side of the electrical circuit. pin section on the positive side of the electrical circuit.
When does current flow through the coil of a solenoid-operated electrical switch? Continually, as long as the aircraft's electrical system master switch is on. Continually, as long as the control circuit is complete. Only until the movable points contact the stationary points.
When a 28 volt, 75 ampere generator is installed on an aircraft, an electrical load analysis ground check is performed and it is determined that the battery is furnishing 57 amperes to the system, with all electrical equipment operating. This indicates the load exceeds the maximum system percentage capacity. that the generator load will exceed the generator limit. the load will be within the generator load limit.
What type of lubricant may be used to aid in pulling electrical wires or cables through conduits? Silicone grease. Soapstone talc. Rubber lubricant.
Which of the following is regulated in a generator to control its voltage output? Speed of the armature. Number of windings in the armature. The strength of the field.
Bonding jumpers should be designed and installed in such a manner that they are not subjected to flexing by relative motion of airframe or engine components. provide a low electrical resistance in the ground circuit. prevent buildup of a static electrical charge between the airframe and the surrounding atmosphere.
When the starter switch to the aircraft gas turbine engine starter-generator is energized and the engine fails to rotate, one of the probable causes would be the power lever switch is defective. undercurrent solenoid contacts are defective. starter solenoid is defective.
Arcing at the brushes and burning of the commutator of a motor may be caused by weak brush springs. excessive brush spring tension. low mica.
The maximum allowable voltage drop between the generator and the bus bar is 1 percent of the regulated voltage. 2 percent of the regulated voltage. less than the voltage drop permitted between the battery and the bus bar.
ON-OFF two position engine electrical switches should be installed so that the toggle will move in the same direction as the desired motion of the unit controlled. under a guard. so the ON position is reached by a forward or upward motion.
When selecting an electrical switch for installation in an aircraft circuit utilizing a direct current motor, a switch designed for dc should be chosen. a derating factor should be applied. only switches with screw-type terminal connections should be used.
When installing electrical wiring parallel to a fuel line, the wiring should be below the fuel line. beside the fuel line. above the fuel line.
(Refer to Figure 4.) In a 28-volt system, what is the maximum continuous current that can be carried by a single No. 10 copper wire 25 feet long, routed in free air? 20 amperes. 35 amperes. 28 amperes.
What speed must an eight-pole ac generator turn to produce 400-Hertz ac? 400 RPM. 1,200 RPM. 6,000 RPM.
How many basic types of circuit breakers are used in powerplant installation electrical systems? Two. Three. Four.
Which Federal Aviation Regulation specifies that each resettable circuit protective device requires a manual operation to restore service after the device has interrupted the circuit? 14 CFR Part 23. 14 CFR Part 43. 14 CFR Part 91.
Which Federal Aviation Regulation requirement prevents the use of automatic reset circuit breakers? 14 CFR Part 21. 14 CFR Part 23. 14 CFR Part 91.
The time/current capacities of a circuit breaker or fuse must be above those of the associated conductor. equal to those of the associated conductor. below those of the associated conductor.
(1) Most modern aircraft use circuit breakers rather than fuses to protect their electrical circuits.
(2) Federal Aviation Regulations Part 23 requires that all electrical circuits incorporate some form of circuit protective device.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Electrical switches are rated according to the voltage and the current they can control. resistance rating of the switch and the wiring. resistance and the temperature rating.
Electrical circuit protection devices are installed primarily to protect the switches. units. wiring.
(1) Electrical circuit protection devices are rated based on the amount of current that can be carried without overheating the wiring insulation.
(2) A 'trip-free' circuit breaker makes it impossible to manually hold the circuit closed when excessive current is flowing.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Which of the following Federal Aviation Regulations require that all aircraft using fuses as the circuit protective devices carry 'one spare set of fuses, or three spare fuses of each kind required'? 14 CFR Part 23. 14 CFR Part 43. 14 CFR Part 91.
What is the smallest terminal stud allowed for aircraft electrical power systems? No. 6. No. 8. No. 10.
A typical barrier type aircraft terminal strip is made of paper-base phenolic compound. polyester resin and graphite compound. layered aluminum impregnated with compound.
A term commonly used when two or more electrical terminals are installed on a single lug of a terminal strip is strapping. piggy backing. stacking.
(1) Electrical wires larger than 10 gauge use uninsulated terminals.
(2) Electrical wires smaller than 10 gauge use uninsulated terminals.
Regarding the above statements, only No. 1 is true. only No. 2 is true. neither No. 1 nor No. 2 is true.
Aircraft electrical wire is manufactured in sizes according to a standard known as Military Specification (MS). American Wire Gauge (AWG). Technical Standard Order (TSO).
Aircraft copper electrical wire is coated with tin, silver, or nickel in order to improve conductivity. add strength. prevent oxidization.
Aircraft wire size is determined by using a(n) ohmmeter. wire gauge. dial caliper.
What will be the result of operating an engine in extremely high temperatures using a lubricant recommended by the manufacturer for a much lower temperature? The oil pressure will be higher than normal. The oil temperature and oil pressure will be higher than normal. The oil pressure will be lower than normal.
(1) Gas turbine and reciprocating engine oils can be mixed or used interchangeably.
(2) Most gas turbine engine oils are synthetic.
Regarding the above statements, only No. 2 is true. both No. 1 and No. 2 are true. neither No. 1 nor No. 2 is true.
An oil separator is generally associated with which of the following? Engine-driven oil pressure pump. Engine-driven vacuum pump. Cuno oil filter.
The time in seconds required for exactly 60 cubic centimeters of oil to flow through an accurately calibrated orifice at a specific temperature is recorded as a measurement of the oil's flash point. specific gravity. viscosity.
Upon what quality or characteristic of a lubricating oil is its viscosity index based? Its resistance to flow at a standard temperature as compared to high grade paraffin-base oil at the same temperature. Its rate of change in viscosity with temperature change. Its rate of flow through an orifice at a standard temperature.
Lubricating oils with high viscosity index ratings are oils in which the viscosity does not vary much with temperature change. in which the viscosity varies considerably with temperature change. which have high SAE numbers.
Compared to reciprocating engine oils, the types of oils used in turbine engines are required to carry and disperse a higher level of combustion by-products. may permit a somewhat higher level of carbon formation in the engine. have less tendency to produce lacquer or coke.
The oil used in reciprocating engines has a relatively high viscosity due to the reduced ability of thin oils to maintain adequate film strength at altitude (reduced atmospheric pressure). the relatively high rotational speeds. large clearances and high operating temperatures.
If all other requirements can be met, what type of oil should be used to achieve theoretically perfect engine lubrication? The thinnest oil that will stay in place and maintain a reasonable film strength. An oil that combines high viscosity and low demulsibility. An oil that combines a low viscosity index and a high neutralization number.
In addition to lubricating (reducing friction between moving parts), engine oil performs what functions?
4. Prevents corrosion.
5. Cushions impact (shock) loads. 1, 2, 3, 4. 1, 2, 3, 4, 5. 1, 3, 4.
Which of these characteristics is desirable in turbine engine oil? Low flash point. High flash point. High volatility.
The viscosity of a liquid is a measure of its resistance to flow. rate of change. weight, or density.
What type of oil system is usually found on turbine engines? Dry sump, pressure, and spray. Dry sump, dip, and splash. Wet sump, spray, and splash.
Which of the following helps determine the proper grade of oil to use in a particular engine? Adequate lubrication in various attitudes of flight. Positive introduction of oil to the bearings. Operating speeds of bearings.
Specific gravity is a comparison of the weight of a substance to the weight of an equal volume of oil at a specific temperature. distilled water at a specific temperature. mercury at a specific temperature.
Which of the following has the greatest effect on the viscosity of lubricating oil? Temperature. Engine RPM. Oil pressure.
What advantage do mineral base lubricants have over vegetable oil base lubricants when used in aircraft engines? Cooling ability. Chemical stability. Friction resistance.
The recommended aircraft engine lubricants are animal, mineral, or synthetic based. mineral or synthetic based. vegetable, mineral, or synthetic based.
High tooth pressures and high rubbing velocities, such as occur with spur-type gears, require the use of an EP lubricant. straight mineral oil. metallic ash detergent oil.
Manufacturers normally require turbine engine oil servicing within a short time after engine shutdown primarily to prevent overservicing. help dilute and neutralize any contaminants that may already be present in the engine's oil system. provide a better indication of any oil leaks in the system.
What type of oil do most engine manufacturers recommend for new reciprocating engine break-in? Ashless-dispersant oil. Straight mineral oil. Semi-synthetic oil.
What type of oil do most engine manufacturers recommend after new reciprocating engine break-in? Metallic-ash detergent oil. Ashless-dispersant oil. Straight mineral oil.
The type of oil pumps most commonly used on turbine engines are classified as positive displacement. variable displacement. constant speed.
As a general rule, the mixture setting on a reciprocating engine operating at or near takeoff power that provides the best cooling is FULL RICH. LEAN. FULL LEAN.
The engine oil temperature regulator is usually located between which of the following on a dry sump reciprocating engine? The engine oil supply pump and the internal lubrication system. The scavenger pump outlet and the oil storage tank. The oil storage tank and the engine oil supply pump.
What will happen to the return oil if the oil line between the scavenger pump and the oil cooler separates? Oil will accumulate in the engine. The return oil will be pumped overboard. The scavenger return line check valve will close and force the oil to bypass directly to the intake side of the pressure pump.
At cruise RPM, some oil will flow through the relief valve of a gear-type engine oil pump. This is normal as the relief valve is set at a pressure which is lower than the pump inlet pressure. lower than the pressure pump capabilities. higher than pressure pump capabilities.
(1) Fuel may be used to cool oil in gas turbine engines.
(2) Ram air may be used to cool oil in gas turbine engines.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
In a reciprocating engine oil system, the temperature bulb senses oil temperature at a point after the oil has passed through the oil cooler. while the oil is in the hottest area of the engine. immediately before the oil enters the oil cooler.
The oil dampened main bearing utilized in some turbine engines is used to provide lubrication of bearings from the beginning of starting rotation until normal oil pressure is established. provide an oil film between the outer race and the bearing housing in order to reduce vibration tendencies in the rotor system, and to allow for slight misalignment. dampen surges in oil pressure to the bearings.
What is the purpose of the last chance oil filters? To prevent damage to the oil spray nozzle. To filter the oil immediately before it enters the main bearings. To assure a clean supply of oil to the lubrication system.
In a jet engine which uses a fuel-oil heat exchanger, the oil temperature is controlled by a thermostatic valve that regulates the flow of fuel through the heat exchanger. both fuel and oil through the heat exchanger. oil through the heat exchanger.
What prevents pressure within the lubricating oil tank from rising above or falling below ambient pressure (reciprocating engine)? Oil tank check valve. Oil pressure relief valve. Oil tank vent.
In an axial-flow turbine engine, compressor bleed air is sometimes used to aid in cooling the fuel. inlet guide vanes. turbine, vanes, blades, and bearings.
Oil picks up the most heat from which of the following turbine engine components? Rotor coupling. Compressor bearing. Turbine bearing.
Which of the following is a function of the fuel-oil heat exchanger on a turbojet engine? Aerates the fuel. Emulsifies the oil. Increases fuel temperature.
According to Federal Aviation Regulations, oil tank fillers on turbine engines must be marked with the word 'oil' and the type and grade of oil specified by the manufacturer. 'oil' and tank capacity. 'oil.'.
Oil tank fillers on reciprocating engines are marked with the word "oil," and tank capacity, in accordance with 14 CFR part 45. "oil," type, and grade, in accordance with 14 CFR part 33. "oil," in accordance with 14 CFR part 23.
After making a welded repair to a pressurized-type turbine engine oil tank, the tank should be pressure checked to not less than 5 PSI plus the maximum operating pressure of the tank. not less than 5 PSI plus the average operating pressure of the tank. 5 PSI.
Why are fixed orifice nozzles used in the lubrication system of gas turbine engines? To provide a relatively constant oil flow to the main bearings at all engine speeds. To keep back pressure on the oil pump, thus preventing an air lock. To protect the oil seals by preventing excessive pressure from entering the bearing cavities.
Possible failure related ferrous-metal particles in turbine engine oil cause an (electrical) indicating-type magnetic chip detector to indicate their presence by disturbing the magnetic lines of flux around the detector tip. bridging the gap between the detector center (positive) electrode and the ground electrode. generating a small electric current that is caused by the particles being in contact with the dissimilar metal of the detector tip.
What would be the probable result if the oil system pressure relief valve should stick in the open position on a turbine engine? Increased oil pressure. Decreased oil temperature. Insufficient lubrication.
What is the primary purpose of the oil-to-fuel heat exchanger? Cool the fuel. Cool the oil. De-aerate the oil.
What unit in an aircraft engine lubrication system is adjusted to maintain the desired system pressure? Oil pressure relief valve. Oil viscosity valve. Oil pump.
Low oil pressure can be detrimental to the internal engine components. However, high oil pressure should be limited to the engine manufacturer's recommendations. has a negligible effect. will not occur because of pressure losses around the bearings.
What is the primary purpose of the oil breather pressurization system that is used on turbine engines? Prevents foaming of the oil. Allows aeration of the oil for better lubrication because of the air/oil mist. Provides a proper oil spray pattern from the main bearing oil jets.
The purpose of directing bleed air to the outer turbine case on some engines is to provide optimum turbine blade tip clearance by controlling thermal expansion. provide up to 100 percent kinetic energy extraction from the flowing gases. allow operation in a thermal environment 600 to 800°F above the temperature limits of turbine blade and vane alloys.
Some larger reciprocating engines use a compensating oil pressure relief valve to provide a high engine oil pressure when the oil is cold and automatically lower the oil pressure when the oil warms up. compensate for changes in atmospheric pressure that accompany altitude changes. automatically keep oil pressure nearly the same whether the oil is warm or cold.
In order to relieve excessive pump pressure in an engine's internal oil system, most engines are equipped with a vent. bypass valve. relief valve.
What is the source of most of the heat that is absorbed by the lubricating oil in a reciprocating engine? Crankshaft main bearings. Exhaust valves. Pistons and cylinder walls.
How are the teeth of the gears in the accessory section of an engine normally lubricated? By splashed or sprayed oil. By submerging the load-bearing portions in oil. By surrounding the load-bearing portions with baffles or housings within which oil pressure can be maintained.
What is the purpose of the check valve generally used in a dry sump lubrication system? To prevent the scavenger pump from losing its prime. To prevent the oil from the supply tank from seeping into the crankcase during inoperative periods. To prevent the oil from the pressure pump from entering the scavenger system.
Which of the following factors has the least effect on the oil consumption of a specific engine? Mechanical efficiency. Engine RPM. Lubricant characteristics.
How is the oil collected by the piston oil ring returned to the crankcase? Down vertical slots cut in the piston wall between the piston oil ring groove and the piston skirt. Through holes drilled in the piston oil ring groove. Through holes drilled in the piston pin recess.
Which of the following lubrication system components is never located between the pressure pump and the engine pressure system? Oil temperature bulb. Fuel line for oil dilution system. Check valve.
As an aid to cold-weather starting, the oil dilution system thins the oil with kerosene. alcohol. gasoline.
The basic oil pressure relief valve setting for a newly overhauled engine is made within the first 30 seconds of engine operation. when the oil is at a higher than normal temperature to assure high oil pressure at normal oil temperature. in the overhaul shop.
Where is the oil temperature bulb located on a dry sump reciprocating engine? Oil inlet line. Oil cooler. Oil outlet line.
Cylinder walls are usually lubricated by splashed or sprayed oil. a direct pressure system fed through the crankshaft, connecting rods, and the piston pins to the oil control ring groove in the piston. oil that is picked up by the oil control ring when the piston is at bottom center.
If an oil filter element becomes completely clogged, the oil flow to the engine will be restricted. oil will be bypassed back to the oil tank. bypass valve will open, and the oil pump will supply unfiltered oil.
Oil accumulation in the cylinders of an inverted in-line engine and in the lower cylinders of a radial engine is normally reduced or prevented by reversed oil control rings. routing the valve-operating mechanism lubricating oil to a separate scavenger pump. extended cylinder skirts.
What is the primary purpose of changing aircraft engine lubricating oils at predetermined periods? The oil becomes diluted with gasoline washing past the pistons into the crankcase. The oil becomes contaminated with moisture, acids, and finely divided suspended solid particles. Exposure to heat and oxygen causes a decreased ability to maintain a film under load.
What determines the minimum particle size which will be excluded or filtered by a cuno-type (stacked disc, edge filtration) filter? The disc thickness. The spacer thickness. Both the number and thickness of the discs in the assembly.
What is the primary purpose of the hopper located in the oil supply tank of some dry sump engine installations? To reduce the time required to warm the oil to operating temperatures. To reduce surface aeration of the hot oil and thus reduce oxidation and the formation of sludge and varnish. To impart a centrifugal motion to the oil entering the tank so that the foreign particles in the oil will separate more readily.
The purpose of the flow control valve in a reciprocating engine oil system is to direct oil through or around the oil cooler. deliver cold oil to the hopper tank. compensate for volumetric increases due to foaming of the oil.
Where are sludge chambers, when used in aircraft engine lubrication systems, usually located? In the crankshaft throws. Adjacent to the scavenger pumps. In the oil storage tank.
Why is an aircraft reciprocating engine oil tank on a dry sump lubrication system equipped with a vent line? To prevent pressure buildup in the reciprocating engine crankcase. To eliminate foaming in the oil tank. To prevent pressure buildup in the oil tank.
Excessive oil is prevented from accumulating on the cylinder walls of a reciprocating engine by the design shape of the piston skirt. internal engine pressure bleeding past the ring grooves. oil control rings on the pistons.
(1) Wet sump oil systems are most commonly used in gas turbine engines.(2) In most turbine engine oil tanks, a slight pressurization of the tank is desired to ensure a positive flow of oil.Regarding the above statements, both No. 1 and No. 2 are true. only No. 2 is true. neither No. 1 nor No. 2 is true.
The pumping capacity of the scavenger pump in a dry sump aircraft engine's lubrication system is greater than the capacity of the oil supply pump. is less than the capacity of the oil supply pump. is usually equal to the capacity of the oil supply pump in order to maintain constant oiling conditions.
In which of the following situations will the oil cooler automatic bypass valve be open the greatest amount? Engine oil above normal operating temperature. Engine oil below normal operating temperature. Engine stopped with no oil flowing after runup.
In order to maintain a constant oil pressure as the clearances between the moving parts of an engine increase through normal wear, the supply pump output increases as the resistance offered to the flow of oil increases with more oil being returned to the pump inlet by the relief valve. remains relatively constant (at a given RPM) with less oil being returned to the pump inlet by the relief valve. remains relatively constant (at a given RPM) with more oil being returned to the pump inlet by the relief valve.
The valve assemblies of opposed reciprocating engines are lubricated by means of a gravity feed system. splash and spray system. pressure system.
What will result if an oil filter becomes completely blocked? Oil will flow at a reduced rate through the system. Oil flow to the engine will stop. Oil will flow at the normal rate through the system.
A turbine engine dry sump lubrication system of the self-contained, high-pressure design has no heat exchanger. consists of pressure, breather, and scavenge subsystems. stores oil in the engine crankcase.
Lube system last chance filters in turbine engines are usually cleaned during annual inspection. during 100-hour inspections. during overhaul.
How are the piston pins of most aircraft engines lubricated? By pressure oil through a drilled passageway in the heavy web portion of the connecting rod. By oil which is sprayed or thrown by the master or connecting rods. By the action of the oil control ring and the series of holes drilled in the ring groove directing oil to the pin and piston pin boss.
The vent line connecting the oil supply tank and the engine in some dry sump engine installations permits pressurization of the oil supply to prevent cavitation of the oil supply pump. oil vapors from the engine to be condensed and drained into the oil supply tank. the oil tank to be vented through the normal engine vent.
An engine lubrication system pressure relief valve is usually located between the oil cooler and the scavenger pump. scavenger pump and the external oil system. pump and the internal oil system.
Where is the oil of a dry sump reciprocating engine exposed to the temperature control valve sensing unit? Oil cooler inlet. Engine outlet. Engine inlet.
Under which of the following conditions is the oil cooler flow control valve open on a reciprocating engine? When the temperature of the oil returning from the engine is too high. When the temperature of the oil returning from the engine is too low. When the scavenger pump output volume exceeds the engine pump input volume.
The purpose of a relief valve installed in the tank venting system of a turbine engine oil tank is to prevent oil pump cavitation by maintaining a constant pressure on the oil pump inlet. maintain internal tank air pressure at the ambient atmospheric level regardless of altitude or rate of change in altitude. maintain a positive internal pressure in the oil tank after shutdown to prevent oil pump cavitation on engine start.
In a reciprocating engine, oil is directed from the pressure relief valve to the inlet side of the scavenger pump. oil temperature regulator. pressure pump.
If the oil in the oil cooler core and annular jacket becomes congealed, what unit prevents damage to the cooler? Oil pressure relief valve. Airflow control valve. Surge protection valve.
The primary source of oil contamination in a normally operating reciprocating engine is metallic deposits as a result of engine wear. atmospheric dust and pollution. combustion deposits due to combustion chamber blow-by and oil migration on the cylinder walls.
A drop in oil pressure may be caused by the temperature regulator sticking open. the bypass valve sticking open. foreign material under the relief valve.
The main oil filters strain the oil at which point in the system? Immediately after it leaves the scavenger pump. Immediately before it enters the pressure pump. Just as it leaves the pressure pump.
Which of the following prevents oil from entering the main accessory case when the engine is not running? Pressure valve. Hydraulic fuse. Check valve.
An oil tank having a capacity of 5 gallons must have an expansion space of 2 quarts. 4 quarts. 5 quarts.
As a general rule, a small amount of small fuzzy particles or gray metallic paste on a turbine engine magnetic chip detector is considered to be the result of normal wear. indicates an imminent component failure. indicates accelerated generalized wear.
Why is expansion space required in an engine oil supply tank? To eliminate oil foaming. For oil enlargement and collection of foam. For proper oil tank ventilation.
The purpose of a dwell chamber in a turbine engine oil tank is to provide a collection point for sediments. for a pressurized oil supply to the oil pump inlet. separation of entrained air from scavenged oil.
Which of the following bearing types must be continuously lubricated by pressure oil? Ball. Roller. Plain.
The magnetic circuit of a magneto consists of a permanent multi-pole rotating magnet. The core is made of hard steel. soft iron. electrical steel.
How is the strength of a magneto magnet checked? Hold the points open and check the output of the primary coil with an ac ammeter while operating the magneto at a specified speed. Check the ac voltage reading at the breaker points. Check the output of the secondary coil with an ac ammeter while operating the magneto at a specified speed.
The E-gap angle is usually defined as the number of degrees between the neutral position of the rotating magnet and the position where the contact points close. where the contact points open. of greatest magnetic flux density.
The greatest density of flux lines in the magnetic circuit of a rotating magnet-type magneto occurs when the magnet is in what position? Full alignment with the field shoe faces. A certain angular displacement beyond the neutral position, referred to as E-gap angle or position. The position where the contact points open.
Magneto breaker point opening relative to the position of the rotating magnet and distributor rotor (internal timing) can be set most accurately during the magneto-to-engine timing operation. during assembly of the magneto before installation on the engine. by setting the points roughly at the required clearance before installing the magneto and then making the fine breaker point adjustment after installation to compensate for wear in the magneto drive train.
Why are high-tension ignition cables frequently routed from the distributors to the spark plugs in flexible metallic conduits? To eliminate high altitude flashover. To reduce the formation of corona and nitric oxide on the cable insulation. To reduce the effect of the high-frequency electromagnetic waves emanated during operation.
What will be the results of increasing the gap of the breaker points in a magneto? Retard the spark and increase its intensity. Advance the spark and decrease its intensity. Retard the spark and decrease its intensity.
What is the purpose of a safety gap in some magnetos? To discharge the secondary coil's voltage if an open occurs in the secondary circuit. To ground the magneto when the ignition switch is off. To prevent flashover in the distributor.
When timing a magneto internally, the alignment of the timing marks indicates that the breaker points are just closing. magnets are in the neutral position. magnets are in the E-gap position.
When internally timing a magneto, the breaker points begin to open when the rotating magnet is fully aligned with the pole shoes. a few degrees past full alignment with the pole shoes. a few degrees past the neutral position.
Magneto timing drift is caused by erosion of the breaker points and excessive spark plug gap. wear of the cam followers. loss of magnetism in the rotor.
What is the electrical location of the primary capacitor in a high-tension magneto? In parallel with the breaker points. In series with the breaker points. In series with the primary and secondary winding.
In a high-tension ignition system, the current in the magneto secondary winding is conducted from the primary winding via the discharge of the capacitor. induced when the primary circuit is interrupted. induced when the primary circuit discharges via the breaker points.
When a 'Shower of Sparks' ignition system is activated at an engine start, a spark plug fires as soon as the advance breaker points open. only while both the retard and advance breaker points are closed. only while both the retard and advance breaker points are open.
What is the radial location of the two north poles of a four-pole rotating magnet in a high-tension magneto? 180° apart. 270° apart. 90° apart.
Magneto pole shoes are generally made of laminations of high-grade soft iron. laminations of high-grade Alnico. pieces of high-carbon iron.
Capacitance afterfiring in most modern spark plugs is reduced by the use of fine wire electrodes. a built-in resistor in each plug. aluminum oxide insulation.
What components make up the magnetic system of a magneto? Pole shoes, the pole shoe extensions, and the primary coil. Primary and secondary coils. Rotating magnet, the pole shoes, the pole shoe extensions, and the coil core.
In an aircraft ignition system, one of the functions of the capacitor is to regulate the flow of current between the primary and secondary coil. facilitate a more rapid collapse of the magnetic field in the primary coil. stop the flow of magnetic lines of force when the points open.
When will the voltage in the secondary winding of a magneto, installed on a normally operating engine, be at its highest value? Just prior to spark plug firing. Toward the latter part of the spark duration when the flame front reaches its maximum velocity. Immediately after the breaker points close.
When the switch is off in a battery ignition system, the primary circuit is grounded. opened. shorted.
As an aircraft engine's speed is increased, the voltage induced in the primary coil of the magneto remains constant. increases. varies with the setting of the voltage regulator.
When internally timing a magneto, the breaker points begin to open when the piston has just passed TDC at the end of the compression stroke. the magnet poles are a few degrees beyond the neutral position. the magnet poles are fully aligned with the pole shoes.
The purpose of a safety gap in a magneto is to prevent burning out the primary winding. protect the high-voltage winding from damage. prevent burning of contact points.
A defective primary capacitor in a magneto is indicated by a fine-grained frosted appearance of the breaker points. burned and pitted breaker points. a weak spark.
How many secondary coils are required in a low-tension ignition system on an 18-cylinder engine? 36 18 9.
A magneto ignition switch is connected in series with the breaker points. parallel to the breaker points. in series with the primary capacitor and parallel to the breaker points.
The spark is produced in a magneto ignition system when the breaker points are fully open. beginning to open. fully closed.
Shielding is used on spark plug and ignition wires to protect the wires from short circuits as a result of chafing or rubbing. prevent outside electromagnetic emissions from disrupting the operation of the ignition system. prevent interference with radio reception.
What is the purpose of using an impulse coupling with a magneto? To absorb impulse vibrations between the magneto and the engine. To compensate for backlash in the magneto and the engine gears. To produce a momentary high rotational speed of the magneto.
The purpose of staggered ignition is to compensate for short ignition harness. rich fuel/air mixture around exhaust valve. diluted fuel/air mixture around exhaust valve.
Aircraft magneto housings are usually ventilated in order to prevent the entrance of outside air which may contain moisture. allow heated air from the accessory compartment to keep the internal parts of the magneto dry. provide cooling and remove corrosive gases produced by normal arcing.
Failure of an engine to cease firing after turning the magneto switch off is an indication of an open high tension lead. an open P-lead to ground. a grounded magneto switch.
Alignment of the marks provided for internal timing of a magneto indicates that the breaker points are just beginning to close for No. 1 cylinder. magneto is in E-gap position. No. 1 cylinder is on TDC of compression stroke.
When using a timing light to time a magneto to an aircraft engine, the magneto switch should be placed in the BOTH position. OFF position. LEFT or RIGHT position (either one).
What is the difference between a low-tension and a high-tension engine ignition system? A low-tension system produces relatively low voltage at the spark plug as compared to a high-tension system. A high-tension system is designed for high-altitude aircraft, while a low-tension system is for low- to medium-altitude aircraft. A low-tension system uses a transformer coil near the spark plugs to boost voltage, while the high-tension system voltage is constant from the magneto to the spark plugs.
What test instrument could be used to test an ignition harness for suspected leakage? A high tension lead tester. A high voltage dc voltmeter. A high amperage dc ammeter.
The amount of voltage generated in any magneto secondary coil is determined by the number of windings and by the rate of buildup of the magnetic field around the primary coil. rate of collapse of the magnetic field around the primary coil. amount of charge released by the capacitor.
Magneto breaker points must be timed to open when the rotating magnet is positioned a few degrees before neutral. greatest magnetic field stress exists in the magnetic circuit. rotating magnet is in the full register position.
In reference to a 'Shower of Sparks' ignition system,
(1) the retard breaker points are designed to keep the affected ignition system operating if the advance breaker points should fail during normal engine operation (after start).
(2) the timed opening of the retard breaker points is designed to prevent engine 'kickback' during start.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
The capacitor-type ignition system is used almost universally on turbine engines primarily because of its high voltage and low amperage. long life. high-heat intensity.
In a low-tension ignition system, each spark plug requires an individual capacitor. breaker assembly. secondary coil.
A certain nine-cylinder radial engine used a noncompensated single-unit, dual-type magneto with a four-pole rotating magnet and separately mounted distributors. Which of the following will have the lowest RPM at any given engine speed? Breaker cam. Engine crankshaft. Distributors.
What will be the effect if the spark plugs are gapped too wide? Insulation failure. Hard starting. Lead damage.
When removing a shielded spark plug, which of the following is most likely to be damaged? Center electrode. Shell section. Core insulator.
What likely effect would a cracked distributor rotor have on a magneto? Ground the secondary circuit through the crack. Fire two cylinders simultaneously. Ground the primary circuit through the crack.
How does the ignition system of a gas turbine engine differ from that of a reciprocating engine? One igniter plug is used in each combustion chamber. Magneto-to-engine timing is not critical. A high-energy spark is required for ignition.
In a turbine engine dc capacitor discharge ignition system, where are the high-voltage pulses formed? At the breaker. At the triggering transformer. At the rectifier.
Which of the following breaker point characteristics is associated with a faulty capacitor? Crowned. Fine grained. Coarse grained.
How are most radial engine spark plug wires connected to the distributor block? By use of cable-piercing screws. By use of self-locking cable ferrules. By use of terminal sleeves and retaining nuts.
Thermocouples are usually inserted or installed on the front cylinder of the engine. rear cylinder of the engine. hottest cylinder of the engine.
Capacitance afterfiring of a spark plug is caused by the stored energy in the ignition shielded lead unloading after normal timed ignition. excessive center electrode erosion. constant polarity firing.
If it is found that a shielded ignition system does not adequately reduce ignition noise, it may be necessary to install a second layer of shielding. a filter between the magneto and magneto switch. bonding wires from the shielding to ground.
When a magneto is operating, what is the probable cause for a shift in internal timing? The rotating magnet loses its magnetism. The distributor gear teeth are wearing on the rotor gear teeth. The cam follower wear and/or the breaker points wear.
Why are turbine engine igniters less susceptible to fouling than reciprocating engine spark plugs? The high-intensity spark cleans the igniter. The frequency of the spark is less for igniters. Turbine igniters operate at cooler temperatures.
The constrained-gap igniter plug used in some gas turbine engines operates at a cooler temperature because it projects into the combustion chamber. the applied voltage is less. the construction is such that the spark occurs beyond the face of the combustion chamber liner.
What should be used to clean grease or carbon tracks from capacitors or coils that are used in magnetos? Solvent. Acetone. Naphtha.
Generally, when removing a turbine engine igniter plug, in order to eliminate the possibility of the technician receiving a lethal shock, the ignition switch is turned off and disconnected from the power supply circuit. the igniter lead is disconnected from the plug and the center electrode grounded to the engine after disconnecting the transformer-exciter input lead and waiting the prescribed time. the transformer-exciter input lead is disconnected and the center electrode grounded to the engine after disconnecting the igniter lead from the plug and waiting the prescribed time.
Great caution should be exercised in handling damaged hermetically sealed turbine engine igniter transformer units because compounds in the unit may become a fire or explosion hazard when exposed to the air. some contain radioactive material. some contain toxic chemicals.
Igniter plugs used in turbine engines have a long service life because they have a high intensity spark. operate continuously with a lower spark. do not require continuous operation.
The electrical circuit from the spark plug back to the magneto is completed by grounding through the engine structure. P-lead. cockpit switch.
Spark plugs are considered worn out when the electrodes have worn away to about one-half of their original dimensions. center electrode edges have become rounded. electrodes have worn away to about two-thirds of their original dimensions.
Which of the following could cause damage to the nose ceramic or to the electrode of an aircraft spark plug? Plug installed without a copper gasket. Improper gapping procedure. Excessive magneto voltage.
Sharp bends should be avoided in ignition leads primarily because weak points may develop in the insulation through which high tension current can leak. ignition lead wire conductor material is brittle and may break. ignition lead shielding effectiveness will be reduced.
In a high-tension ignition system, a primary capacitor of too low a capacity will cause excessive primary voltage. excessively high secondary voltage. the breaker contacts to burn.
Which of the following, obtained during magneto check at 1,700 RPM, indicates a short (grounded) circuit between the right magneto primary and the ignition switch? BOTH -- 1,700 RPM, R -- 1,625 RPM, L -- 1,700 RPM, OFF -- 1,625 RPM. BOTH -- 1,700 RPM, R -- 0 RPM, L -- 1,700 RPM, OFF -- 0 RPM. BOTH -- 1,700 RPM, R -- 0 RPM, L -- 1,675 RPM, OFF -- 0 RPM.
If an aircraft ignition switch is turned off and the engine continues to run normally, the trouble is probably caused by an open ground lead in the magneto. arcing magneto breaker points. primary lead grounding.
Which statement is correct regarding the ignition system of a turbine engine? The system is normally de-energized as soon as the engine starts. It is energized during the starting and warmup periods only. The system generally includes a polar inductor-type magneto.
When the ignition switch of a single (reciprocating) engine aircraft is turned to the OFF position, the primary circuits of both magnetos are grounded. the secondary circuits of both magnetos are opened. all circuits are automatically opened.
A spark plug's heat range is the result of the area of the plug exposed to the cooling airstream. its ability to transfer heat from the firing end of the spark plug to the cylinder head. the heat intensity of the spark.
If staggered ignition timing is used, the spark plug nearest the exhaust valve will fire first. spark will be automatically advanced as engine speed increases. spark plug nearest the intake valve will fire first.
The term 'reach,' as applied to spark plug design and/or type, indicates the linear distance from the shell gasket seat to the end of the threads on the shell skirt. length of center electrode exposed to the flame of combustion. length of the shielded barrel.
The numbers appearing on the ignition distributor block indicate the sparking order of the distributor. relation between distributor terminal numbers and cylinder numbers. firing order of the engine.
When testing a magneto distributor block for electrical leakage, which of the following pieces of test equipment should be used? A high-tension harness tester. A continuity tester. A high-range ammeter.
(1) The platinum and iridium ground electrodes used on fine wire spark plugs are extremely brittle and can be broken if they are improperly handled or adjusted.
(2) When gapping massive-electrode spark plugs, a wire gauge should be inserted between the center and ground electrodes while moving the ground electrode in order to avoid setting the gap too close.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Hot spark plugs are generally used in aircraft powerplants with comparatively high compression or high operating temperatures. with comparatively low operating temperatures. which produce high power per cubic inch displacement.
If a spark plug lead becomes grounded, the magneto will not be affected. distributor rotor finger will discharge to the next closest electrode within the distributor. capacitor will break down.
Which of the following statements regarding magneto switch circuits is NOT true? In the BOTH position, the right and left magneto circuits are grounded. In the OFF position, neither the right nor left magneto circuits are open. In the RIGHT position, the right magneto circuit is open and the left magneto circuit is grounded.
Which of the following statements most accurately describes spark plug heat range? The length of the threaded portion of the shell usually denotes the spark plug heat range. A hot plug is designed so that the insulator tip is reasonably short to hasten the rate of heat transfer from the tip through the spark plug shell to the cylinder head. A cold plug is designed so that the insulator tip is reasonably short to hasten the rate of heat transfer from the tip through the spark plug shell to the cylinder head.
When does battery current flow through the primary circuit of a battery ignition coil? Only when the breaker points are open. At all times when the ignition switch is on. When the breaker points are closed and the ignition switch is on.
In order to turn a magneto off, the primary circuit must be grounded. opened. shorted.
When performing a magneto ground check on an engine, correct operation is indicated by a slight increase in RPM. no drop in RPM. a slight drop in RPM.
Defective spark plugs will cause the engine to run rough during run up. during cruise. at all speeds.
A spark plug is fouled when its spark grounds by jumping electrodes. it causes preignition. its spark grounds without jumping electrodes.
Which of the following would be cause for rejection of a spark plug? Carbon fouling of the electrode and insulator. Insulator tip cracked. Lead fouling of the electrode and insulator.
What will be the result of using too hot a spark plug? Fouling of plug. Preignition. Burned capacitor.
Upon inspection of the spark plugs in an aircraft engine, the plugs were found caked with a heavy black soot. This indicates worn oil seal rings. a rich mixture. a lean mixture.
Spark plug heat range is determined by the reach of the spark plug. its ability to transfer heat to the cylinder head. the number of ground electrodes.
Ignition check during engine runup indicates excessive RPM drop during operation on the right magneto. The major portion of the RPM loss occurs rapidly after switching to the right magneto position (fast drop). The most likely cause is faulty or fouled spark plugs. incorrect ignition timing on both magnetos. one or more dead cylinders.
If new breaker points are installed in a magneto on an engine, it will be necessary to time the magneto internally and the magneto to the engine. breaker points to the No. 1 cylinder. magneto drive to the engine.
Using a cold spark plug in a high-compression aircraft engine would probably result in normal operation. a fouled plug. detonation.
Spark plug fouling caused by lead deposits occurs most often during cruise with rich mixture. when cylinder head temperatures are relatively low. when cylinder head temperatures are high.
In a four-stroke cycle aircraft engine, when does the ignition event take place? Before the piston reaches TDC on compression stroke. After the piston reaches TDC on power stroke. After the piston reaches TDC on compression stroke.
When installing a magneto on an engine, the piston in the No. 1 cylinder must be a prescribed number of degrees before top center on the compression stroke. magneto breaker points must be just closing. piston in the No. 1 cylinder must be a prescribed number of degrees after top center on the intake stroke.
The spark occurs at the spark plug when the ignition's secondary circuit is completed. primary circuit is completed. primary circuit is broken.
The type of ignition system used on most turbine aircraft engines is high resistance. low tension. capacitor discharge.
Ignition check during engine runup indicates a slow drop in RPM. This is usually caused by defective spark plugs. a defective high-tension lead. incorrect ignition timing or valve adjustment.
If the ground wire of a magneto is disconnected at the ignition switch, the result will be the affected magneto will be isolated and the engine will run on the opposite magneto. engine will stop running. engine will not stop running when the ignition switch is turned off.
Advantages of dual ignition in aircraft engines include providing a backup magneto system, increasing the output power of the engine, and permitting the use of lower grade fuels. increasing the intensity of the spark at the spark plugs. increasing the output power of the engine.
How does high-tension ignition shielding tend to reduce radio interference? Prevents ignition flashover at high altitudes. Reduces voltage drop in the transmission of high-tension current. Receives and grounds high-frequency waves coming from the magneto and high-tension ignition leads.
Which of the following are distinct circuits of a high tension magneto? Magnetic, primary, and secondary. Magnetic, E-gap, and P lead. Primary, P lead, and secondary.
What are two parts of a distributor in an aircraft engine ignition system?
5. Transformer. 2 and 4. 3 and 4. 2 and 5.
What is a result of 'flashover' in a distributor? Intense voltage at the spark plug. Reversal of current flow. Conductive carbon trail.
What is the relationship between distributor and crankshaft speed of aircraft reciprocating engines? The distributor turns at one-half crankshaft speed. The distributor turns at one and one-half crankshaft speed. The crankshaft turns at one-half distributor speed.
Why do turbine engine ignition systems require high energy? To ignite the fuel under conditions of high altitude and high temperatures. Because the applied voltage is much greater. To ignite the fuel under conditions of high altitude and low temperatures.
Which of the following are included in a typical turbine engine ignition system?
1. Two igniter plugs.
2. Two transformers.
3. One exciter unit.
4. Two intermediate ignition leads.
5. Two low-tension igniter leads.
6. Two high-tension igniter leads. 2, 3, 4. 1, 4, 5. 1, 3, 6.
At what RPM is a reciprocating engine ignition switch check made? 1,500 RPM. The slowest possible RPM. Full throttle RPM.
What is the approximate position of the rotating magnet in a high-tension magneto when the points first close? Full register. Neutral. A few degrees after neutral.
What component of a dual magneto is shared by both ignition systems? High-tension coil. Rotating magnet. Capacitor.
What would be the result if a magneto breaker point mainspring did not have sufficient tension? The points will stick. The points will not open to the specified gap. The points will float or bounce.
The secondary coil of a magneto is grounded through the ignition switch. primary coil. ground side of the breaker points.
In the aircraft magneto system, if the P-lead is disconnected, the magneto will be on regardless of ignition switch position. grounded regardless of ignition switch position. open regardless of ignition switch position.
(Refer to Figure 5.) With power applied to the bus bar, what switch changes will allow the ignition exciters test switch to function? Engine master switch, battery switch, and power lever switch. Engine master switch, start switch, and test switch. Engine master switch and ignition switch.
(Refer to Figure 5.) The type of system depicted is capable of operating with external power only. either battery or external power. battery power and external power simultaneously.
(Refer to Figure 5.) If wire No. 8 is broken or disconnected after starter rotation is initiated, and the power lever is advanced, the starting sequence will continue normally. starter will shut down, but the igniters will continue to fire. starting sequence will discontinue.
(Refer to Figure 5.) When an external power source is connected to the aircraft, the battery cannot be connected to the bus. both battery power and external power are available to the bus. the starter relay coil has a path to ground.
The purpose of an under current relay in a starter-generator system is to provide a backup for the starter relay. disconnect power from the starter-generator and ignition when sufficient engine speed is reached. keep current flow to the starter-generator under the circuit capacity maximum.
In a typical starter-generator system, under which of the following starting circumstances may it be necessary to use the start stop button? Hung start. Hot start. Contacts stick open.
(Refer to Figure 5.) Which malfunctions will allow the igniters to operate when tested but be inoperative during a start attempt?
1. Conductor No. 10 broken.
2. Conductor No. 11 broken.
3. Ignition relay inoperative.
4. Conductor No. 12 broken. 1 or 4. 2 or 3. 1 or 3.
(Refer to Figure 5.) Which malfunctions will allow the igniters to operate normally during start but be inoperative when tested?
1. Conductor No. 14 broken.
2. Conductor No. 10 broken.
3. Conductor No. 15 broken.
4. Conductor No. 12 broken. 2 or 4. 1 or 3. 3 or 4.
When using an electric starter motor, current usage is highest at the start of motor rotation. remains relatively constant throughout the starting cycle. is highest just before starter cutoff (at highest RPM).
When using an electric starter motor, the current flow through it is highest just before starter cutoff (at highest RPM). remains relatively constant throughout the starting cycle. is highest at the start of motor rotation.
The primary advantage of pneumatic (air turbine) starters over comparable electric starters for turbine engines is a significant lack of wear to the commutator. that it does not disengage until the engine reaches idle. high power-to-weight ratio.
A clicking sound heard at engine coast-down in a pneumatic starter incorporating a sprag clutch ratchet assembly is an indication of gear tooth and/or pawl damage. one or more broken pawl springs. the pawls re-contacting and riding on the ratchet gear.
Pneumatic starters are usually designed with what types of airflow impingement systems? Radial inward flow turbine and axial-flow turbine. Centrifugal compressor and axial-flow compressor. Double entry centrifugal outward flow and axial-flow turbines.
Inspection of pneumatic starters by maintenance technicians usually includes checking the oil level and magnetic drain plug condition. stator and rotor blades for FOD. rotor alignment.
Air turbine starters are generally designed so that reduction gear distress or damage may be detected by characteristic sounds from the starter assembly during engine start. breakage of a shear section on the starter drive shaft. inspection of a magnetic chip detector.
Airflow to the pneumatic starter from a ground unit is normally prevented from causing starter overspeed during engine start by stator nozzle design that chokes airflow and stabilizes turbine wheel speed. activation of a flyweight cutout switch. a preset timed cutoff of the airflow at the source.
A safety feature usually employed in pneumatic starters that is used if the clutch does not release from the engine drive at the proper time during start is the flyweight cutout switch. spring coupling release. drive shaft shear point.
A safety feature usually employed in direct-cranking starters that is used to prevent the starter from reaching burst speed is the drive shaft shear point. stator nozzle design that chokes airflow and stabilizes turbine wheel speed. spring coupling release.
In the event a pneumatic start valve will not operate and the manual override must be used, the starter T-handle must be closed at scheduled starter drop out because the starter will overheat. the starter will overspeed at a given N^2. the starter oil will be blown overboard.
(Refer to Figure 5.) With power applied to the bus bar, what wire supplies standby power to the starter relay contact? 4. 7. 8.
What factor is not used in the operation of an aircraft gas turbine engine fuel control unit? Compressor inlet air temperature. Mixture control position. Power lever position.
In order to stabilize cams, springs, and linkages within the fuel control, manufacturers generally recommend that all final turbine engine trim adjustments be made in the increase direction. decrease direction. decrease direction after over-adjustment.
When trimming a turbine engine, the fuel control is adjusted to produce as much power as the engine is capable of producing. set idle RPM and maximum speed or EPR. allow the engine to produce maximum RPM without regard to power output.
An electronic engine control (EEC) is a system that receives engine operating information and adjusts a standard hydromechanical fuel control unit to obtain the most effective engine operation. develops the commands to various actuators to control engine parameters. controls engine operation according to ambient temperature, pressure, and humidity.
A full-authority electronic engine control (EEC) is a system that receives all the necessary data for engine operation and adjusts a standard hydromechanical fuel control unit to obtain the most effective engine operation. develops the commands to various actuators to control engine parameters. controls engine operation according to ambient temperature, pressure, and humidity.
In a supervisory EEC system, any fault in the EEC that adversely affects engine operation causes redundant or backup units to take over and continue normal operation. usually degrades performance to the extent that continued operation can cause damage to the engine. causes an immediate reversion to control by the hydromechanical fuel control unit.
The active clearance control (ACC) portion of an EEC system aids turbine engine efficiency by adjusting stator vane position according to operating conditions and power requirements. ensuring turbine blade to engine case clearances are kept to a minimum by controlling case temperatures. automatically adjusting engine speed to maintain a desired EPR.
What should be checked/changed to ensure the validity of a turbine engine performance check if an alternate fuel is to be used? Fuel specific gravity setting. Maximum RPM adjustment. EPR gauge calibration.
Prior to performing engine trimming, you should call the control tower to obtain current sea level barometric pressure and temperature. observe the reading on the aircraft Outside Air Temperature (OAT) gauge. obtain a true temperature reading comparable to that of the air that enters the engine.
An aircraft should be facing into the wind when trimming an engine. However, if the velocity of the wind blowing into the intake is excessive, it is likely to cause a false low exhaust gas temperature reading. trim setting resulting in engine overspeed. false high compression and turbine discharge pressure, and a subsequent low trim.
Generally, the practice when trimming an engine is to turn all accessory bleed air off. turn all accessory bleed air on. make adjustments (as necessary) for all engines on the same aircraft with accessory bleed air settings the same -- either on or off.
Which of the following best describes the function of an automatic mixture control (AMC)? It compensates for change in the air density due to temperature and altitude. It compensates for the air pressure above the fuel in the float chamber. It compensates for the air pressure in the venturi of a float-type carburetor.
On a float-type carburetor, the purpose of the economizer valve is to provide extra fuel for sudden acceleration of the engine. maintain the leanest mixture possible during cruising best power. provide a richer mixture and cooling at maximum power output.
The fuel metering force of a conventional float-type carburetor in its normal operating range is the difference between the pressure acting on the discharge nozzle located within the venturi and the pressure acting on the fuel in the float chamber. of the fuel as it enters the carburetor. of the air as it enters the venturi (impact pressure).
If the main air bleed of a float-type carburetor becomes clogged, the engine will run lean at rated power. rich at rated power. rich at idling.
Which method is commonly used to adjust the level of a float in a float-type carburetor? Lengthening or shortening the float shaft. Add or remove shims under the needle-valve seat. Change the angle of the float arm pivot.
What is the possible cause of an engine running rich at full throttle if it is equipped with a float-type carburetor? Float level too low. Clogged main air bleed. Clogged atmospheric vent.
One of the things a metering orifice in a main air bleed helps to accomplish (at a given altitude) in a carburetor is pressure in the float chamber to increase as airflow through the carburetor increases. a progressively richer mixture as airflow through the carburetor increases. better fuel vaporization and control of fuel discharge, especially at lower engine speeds.
A punctured float in a float-type carburetor will cause the fuel level to lower, and enrich the mixture. rise, and enrich the mixture. rise, and lean the mixture.
The back-suction mixture control system operates by varying the pressure within the venturi section. varying the pressure acting on the fuel in the float chamber. changing the effective cross-sectional area of the main metering orifice (jet).
If an aircraft engine is equipped with a carburetor that is not compensated for altitude and temperature variations, the fuel/air mixture will become leaner as either the altitude or temperature increases. richer as the altitude increases and leaner as the temperature increases. richer as either the altitude or temperature increases.
Float-type carburetors which are equipped with economizers are normally set for their richest mixture delivery and leaned by means of the economizer system. the economizer system to supplement the main system supply at all engine speeds above idling. their leanest practical mixture delivery at cruising speeds and enriched by means of the economizer system at higher power settings.
If a float-type carburetor becomes flooded, the condition is most likely caused by a leaking needle valve and seat assembly. the accelerating pump shaft being stuck. a clogged back-suction line.
If an engine is equipped with a float-type carburetor and the engine runs excessively rich at full throttle, a possible cause of the trouble is a clogged main air bleed. back-suction line. atmospheric vent line.
What occurs when a back-suction type mixture control is placed in IDLE CUTOFF? The fuel passages to the main and idle jets will be closed by a valve. The float chamber will be vented to a negative pressure area. The fuel passage to the idle jet will be closed by a valve.
Which of the following best describes the function of an altitude mixture control? Regulates the richness of the fuel/air charge entering the engine. Regulates the air pressure above the fuel in the float chamber. Regulates the air pressure in the venturi.
Select the correct statement concerning the idle system of a conventional float-type carburetor. The low-pressure area created in the throat of the venturi pulls the fuel from the idle passage. Climatic conditions have very little effect on idle mixture requirements. The low pressure between the edges of the throttle valve and the throttle body pulls the fuel from the idle passage.
On an engine equipped with a pressure-type carburetor, fuel supply in the idling range is ensured by the inclusion in the carburetor of a spring in the unmetered fuel chamber to supplement the action of normal metering forces. an idle metering jet that bypasses the carburetor in the idle range. a separate boost venturi that is sensitive to the reduced airflow at start and idle speeds.
The economizer system of a float-type carburetor performs which of the following functions? It supplies and regulates the fuel required for all engine speeds. It supplies and regulates the additional fuel required for all engine speeds above cruising. It regulates the fuel required for all engine speeds and all altitudes.
How will the mixture of an engine be affected if the bellows of the automatic mixture control (AMC) in a pressure carburetor ruptures while the engine is operating at altitude? It will become leaner. No change will occur until the altitude changes. It will become richer.
The fuel level within the float chamber of a properly adjusted float-type carburetor will be slightly higher than the discharge nozzle outlet. slightly lower than the discharge nozzle outlet. at the same level as the discharge nozzle outlet.
The metered fuel pressure (chamber C) in an injection-type carburetor is held constant throughout the entire engine operating range. varies according to the position of the poppet valve located between chamber D (unmetered fuel) and chamber E (engine-driven fuel pump pressure). will be approximately equal to the pressure in chamber A (impact pressure).
Select the statement which is correct relating to a fuel level check of a float-type carburetor. Use 5 pounds fuel pressure for the test if the carburetor is to be used in a gravity fuel feed system. Block off the main and idle jets to prevent a continuous flow of fuel through the jets. Do not measure the level at the edge of the float chamber.
What carburetor component measures the amount of air delivered to the engine? Economizer valve. Automatic mixture control. Venturi.
If fuel is found running from the carburetor with the engine not running, the likely cause is that the float needle valve is not seated properly. float level is adjusted too low. main air bleed is clogged.
Fuel is discharged for idling speeds on a float-type carburetor from the idle discharge nozzle. in the venturi. through the idle discharge air bleed.
When air passes through the venturi of a carburetor, what three changes occur? Velocity increases, temperature increases, and pressure decreases. Velocity decreases, temperature increases, and pressure increases. Velocity increases, temperature decreases, and pressure decreases.
Where is the throttle valve located on a float-type carburetor? Between the venturi and the discharge nozzle. After the main discharge nozzle and venturi. After the venturi and just before the main discharge nozzle.
An aircraft carburetor is equipped with a mixture control in order to prevent the mixture from becoming too lean at high altitudes. rich at high altitudes. rich at high speeds.
Which of the following is NOT a function of the carburetor venturi? Proportions the fuel/air mixture. Regulates the idle system. Limits the airflow at full throttle.
Idle cutoff is accomplished on a carburetor equipped with a back-suction mixture control by introducing low pressure (intake manifold) air into the float chamber. turning the fuel selector valve to OFF. the positive closing of a needle and seat.
One purpose of an air bleed in a float-type carburetor is to increase fuel flow at altitude. meter air to adjust the mixture. decrease fuel density and destroy surface tension.
To determine the float level in a float-type carburetor, a measurement is usually made from the top of the fuel in the float chamber to the parting surface of the carburetor. top of the float. centerline of the main discharge nozzle.
The throttle valve of float-type aircraft carburetors is located ahead of the venturi and main discharge nozzle. after the main discharge nozzle and ahead of the venturi. between the venturi and the engine.
Why must a float-type carburetor supply a rich mixture during idle? Engine operation at idle results in higher than normal volumetric efficiency. Because at idling speeds the engine may not have enough airflow around the cylinders to provide proper cooling. Because of reduced mechanical efficiency during idle.
What component is used to ensure fuel delivery during periods of rapid engine acceleration? Acceleration pump. Engine-driven fuel pump. Power enrichment unit.
The device that controls the ratio of the fuel/air mixture to the cylinders is called a throttle valve. mixture control. metering jet.
The device that controls the volume of the fuel/air mixture to the cylinders is called a mixture control. metering jet. throttle valve.
Which statement is correct regarding a continuous-flow fuel injection system used on many reciprocating engines? Fuel is injected directly into each cylinder. Fuel is injected at each cylinder intake port. Two injector nozzles are used in the injector fuel system for various speeds.
During the operation of an aircraft engine, the pressure drop in the carburetor venturi depends primarily upon the air temperature. barometric pressure. air velocity.
Which of the following causes a single diaphragm accelerator pump to discharge fuel? An increase in venturi suction when the throttle valve is open. An increase in manifold pressure that occurs when the throttle valve is opened. A decrease in manifold pressure that occurs when the throttle valve is opened.
At what engine speed does the main metering jet actually function as a metering jet in a float-type carburetor? All RPM's. Cruising RPM only. All RPM's above idle range.
An aircraft engine continuous cylinder fuel injection system normally discharges fuel during which stroke(s)? Intake. Intake and compression. All (continuously).
What is the purpose of the carburetor accelerating system? Supply and regulate the fuel required for engine speeds above idle. Temporarily enrich the mixture when the throttle is suddenly opened. Supply and regulate additional fuel required for engine speeds above cruising.
When troubleshooting an engine that will not idle, what would be a probable cause? Economizer valve not operating correctly. Mixture setting too rich. Manifold valve is not operating properly.
What is the relationship between the accelerating pump and the enrichment valve in a pressure injection carburetor? No relationship since they operate independently. Unmetered fuel pressure affects both units. The accelerating pump actuates the enrichment valve.
What is the relationship between the pressure existing within the throat of a venturi and the velocity of the air passing through the venturi? There is no direct relationship between the pressure and the velocity. The pressure is directly proportional to the velocity. The pressure is inversely proportional to the velocity.
Which of the following is least likely to occur during operation of an engine equipped with a direct cylinder fuel injection system? Afterfiring. Kickback during start. Backfiring.
What carburetor component limits the maximum airflow into the engine at full throttle? Throttle valve. Venturi. Main metering jet.
On a carburetor without an automatic mixture control as you ascend to altitude, the mixture will be enriched. be leaned. not be affected.
During engine operation, if carburetor heat is applied, it will increase fuel/air ratio. increase engine RPM. decrease the air density to the carburetor.
The desired engine idle speed and mixture setting is adjusted with engine warmed up and operating. should give minimum RPM with maximum manifold pressure. is usually adjusted in the following sequence; speed first, then mixture.
A nine-cylinder radial engine, using a multiple-point priming system with a central spider, will prime which cylinders? One, two, three, eight, and nine. All cylinders. One, three, five, and seven.
What is a function of the idling air bleed in a float-type carburetor? It provides a means for adjusting the mixture at idle speeds. It vaporizes the fuel at idling speeds. It aids in emulsifying/vaporizing the fuel at idle speeds.
If the volume of air passing through a carburetor venturi is reduced, the pressure at the venturi throat will decrease. be equal to the pressure at the venturi outlet. increase.
(Refer to Figure 6.) Which curve most nearly represents an aircraft engine's fuel/air ratio throughout its operating range? 1 3 2.
What will occur if the vapor vent float in a pressure carburetor loses its buoyancy? The amount of fuel returning to the fuel tank from the carburetor will be increased. The engine will continue to run after the mixture control is placed in IDLE CUTOFF. A rich mixture will occur at all engine speeds.
What method is ordinarily used to make idle speed adjustments on a float-type carburetor? An adjustable throttle stop or linkage. An orifice and adjustable tapered needle. An adjustable needle in the drilled passageway which connects the airspace of the float chamber and the carburetor venturi.
For what primary purpose is a turbine engine fuel control unit trimmed? To obtain maximum thrust output when desired. To properly position the power levers. To adjust the idle RPM.
Which type of fuel control is used on most of today's turbine engines? Electromechanical. Mechanical. Hydromechanical or electronic.
Under which of the following conditions will the trimming of a turbine engine be most accurate? High wind and high moisture. High moisture and low wind. No wind and low moisture.
(1) The mixture used at rated power in air cooled reciprocating engines is richer than the mixture used through the normal cruising range.
(2) The mixture used at idle in air cooled reciprocating engines is richer than the mixture used at rated power.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Under which of the following conditions would an engine run lean even though there is a normal amount of fuel present? The use of too high an octane rating fuel. Incomplete fuel vaporization. The carburetor air heater valve in the HOT position.
During idle mixture adjustments, which of the following is normally observed to determine when the correct mixture has been achieved? Changes in fuel/air pressure ratio. Fuel flowmeter. Changes in RPM or manifold pressure.
An indication that the optimum idle mixture has been obtained occurs when the mixture control is moved to IDLE CUTOFF and manifold pressure decreases momentarily and RPM drops slightly before the engine ceases to fire. increases momentarily and RPM drops slightly before the engine ceases to fire. decreases and RPM increases momentarily before the engine ceases to fire.
The use of less than normal throttle opening during starting will cause a rich mixture. a lean mixture. backfire due to lean fuel/air ratio.
When checking the idle mixture on a carburetor, the engine should be idling normally, then pull the mixture control toward the IDLE CUTOFF position. A correct idling mixture will be indicated by an immediate decrease in RPM. a decrease of 20 to 30 RPM before quitting. an increase of 10 to 50 RPM before decreasing.
When a new carburetor is installed on an engine, warm up the engine and adjust the float level. do not adjust the idle mixture setting; this was accomplished on the flow bench. and the engine is warmed up to normal temperatures, adjust the idle mixture, then the idle speed.
The purpose of the back-suction mixture control in a float-type carburetor is to adjust the mixture by regulating the pressure drop at the venturi. regulating the pressure on the fuel in the float chamber. regulating the suction on the mixture from behind the throttle valve.
Reciprocating engine power will be decreased at all altitudes if the air density is increased. humidity is increased. manifold pressure is increased.
If the idling jet becomes clogged in a float-type carburetor, the engine operation will not be affected at any RPM. engine will not idle. idle mixture becomes richer.
An aircraft engine equipped with a pressure-type carburetor is started with the primer while the mixture control is positioned at IDLE CUTOFF. mixture control in the FULL-RICH position. primer while the mixture control is positioned at the FULL-LEAN position.
One of the best ways to increase engine power and control detonation and preignition is to enrich the fuel/air mixture. use water injection. lean the fuel/air mixture.
An excessively lean fuel/air mixture may cause an increase in cylinder head temperature. high oil pressure. backfiring through the exhaust.
The density of air is very important when mixing fuel and air to obtain a correct fuel-to-air ratio. Which of the following weighs the most? 75 parts of dry air and 25 parts of water vapor. 100 parts of dry air. 50 parts of dry air and 50 parts of water vapor.
A mixture ratio of 11:1 normally refers to a stoichiometric mixture. 1 part air to 11 parts fuel. 1 part fuel to 11 parts air.
The economizer system in a float-type carburetor keeps the fuel/air ratio constant. functions only at cruise and idle speeds. increases the fuel/air ratio at high power settings.
A carburetor is prevented from leaning out during quick acceleration by the power enrichment system. mixture control system. accelerating system.
In turbine engines that utilize a pressurization and dump valve, the dump portion of the valve cuts off fuel flow to the engine fuel manifold and dumps the manifold fuel into the combustor to burn just before the engine shuts down. drains the engine manifold lines to prevent fuel boiling and subsequent deposits in the lines as a result of residual engine heat (at engine shutdown). dumps extra fuel into the engine in order to provide for quick engine acceleration during rapid throttle advancement.
What effect does high atmospheric humidity have on the operation of a jet engine? Decreases engine pressure ratio. Decreases compressor and turbine RPM. Has little or no effect.
What are the positions of the pressurization valve and the dump valve in a jet engine fuel system when the engine is shut down? Pressurization valve closed, dump valve open. Pressurization valve open, dump valve open. Pressurization valve closed, dump valve closed.
What could cause a lean mixture and high cylinder head temperature at sea level or low altitudes? Mixture control valve fully closed. Defective accelerating system. Automatic mixture control stuck in the extended position.
Which of the following is NOT an input parameter for a turbine engine fuel control unit? Compressor inlet pressure. Compressor inlet temperature. Ambient humidity.
Detonation occurs when the fuel/air mixture burns too fast. ignites before the time of normal ignition. is too rich.
What corrective action should be taken when a carburetor is found to be leaking fuel from the discharge nozzle? Replace the needle valve and seat. Adjust the mixture control. Adjust throttle linkage.
A major difference between the Teledyne-Continental and RSA (Precision Airmotive or Bendix) continuous flow fuel injection systems in fuel metering is that the RSA system uses air pressure only as a metering force. Continental system utilizes airflow as a metering force. Continental system uses fuel pressure only as a metering force.
The function of the altitude compensating, or aneroid valve used with the Teledyne-Continental fuel injection system on many turbocharged engines is to prevent an overly rich mixture during sudden acceleration. prevent detonation at high altitudes. provide a means of enriching the mixture during sudden acceleration.
The primary purpose of the air bleed openings used with continuous flow fuel injector nozzles is to provide for automatic mixture control. maintain constant fuel pressure. aid in proper fuel vaporization.
During what period does the fuel pump bypass valve open and remain open? When the fuel pump pressure is greater than the demand of the engine. When the boost pump pressure is greater than fuel pump pressure. When the fuel pump output is greater than the demand of the carburetor.
Which of the following statements concerning a centrifugal-type fuel boost pump located in a fuel supply tank is NOT true? Air and fuel vapors do not pass through a centrifugal-type pump. Fuel can be drawn through the impeller section of the pump when it is not in operation. The centrifugal-type pump is classified as a positive displacement pump.
Where is the engine fuel shutoff valve usually located? Aft of the firewall. Adjacent to the fuel pump. Downstream of the engine-driven fuel pump.
Boost pumps in a fuel system operate during takeoff only. are primarily used for fuel transfer. provide a positive flow of fuel to the engine pump.
(Refer to Figure 7.) What is the purpose of the fuel transfer ejectors? To supply fuel under pressure to the engine-driven pump. To assist in the transfer of fuel from the main tank to the boost pump sump. To transfer fuel from the boost pump sump to the wing tank.
What is the purpose of an engine-driven fuel pump bypass valve? To divert the excess fuel back to the main tank. To prevent a damaged or inoperative pump from blocking the fuel flow of another pump in series with it. To divert the excess fuel from the pressure side of the pump to the inlet side of the pump.
Most large aircraft reciprocating engines are equipped with which of the following types of engine-driven fuel pumps? Rotary-vane-type fuel pump. Centrifugal-type fuel pump. Gear-type fuel pump.
When an electric primer is used, fuel pressure is built up by the internal pump in the primer solenoid. suction at the main discharge nozzle. booster pump.
The fuel pump relief valve directs excess fuel to the fuel tank return line. inlet side of the fuel pump. inlet side of the fuel strainer.
Which type of pump is commonly used as a fuel pump on reciprocating engines? Gear. Impeller. Vane.
The purpose of the diaphragm in most vane-type fuel pumps is to maintain fuel pressure below atmospheric pressure. equalize fuel pressure at all speeds. compensate fuel pressures to altitude changes.
The primary condition(s) that allow(s) microorganisms to grow in the fuel in aircraft fuel tanks is (are) warm temperatures. the presence of water. the presence of dirt or other particulate contaminants.
It is desirable that fuel lines have a gentle slope upward or downward and not have sharp curves or sharp rises and/or falls in order to prevent vapor lock. prevent stagnation or 'pooling' of fuel in the fuel lines. minimize the generation of static electricity by decreasing fluid friction in the lines.
The fuel systems of aircraft certificated in the standard classification must include which of the following? An engine-driven fuel pump and at least one auxiliary pump per engine. A positive means of shutting off the fuel to all engines. A reserve supply of fuel, available to the engine only after selection by the flightcrew, sufficient to operate the engines at least 30 minutes at METO power.
Where is the main fuel strainer located in the aircraft fuel system? At the highest point in the fuel system. At the lowest point in the fuel system. At the inlet chamber of the carburetor.
Where physical separation of the fuel lines from electrical wiring or conduit is impracticable, locate the fuel line below the wiring and clamp the line securely to the airframe structure. above the wiring and clamp the line securely to the airframe structure. inboard of the wiring and clamp both securely to the airframe structure.
What is a characteristic of a centrifugal-type fuel boost pump? It separates air and vapor from the fuel. It has positive displacement. It requires a relief valve.
The Federal Aviation Regulations require the fuel flow rate for gravity systems (main and reserve) to be 125 percent of the takeoff fuel consumption of the engine. 125 percent of the maximum, except takeoff, fuel consumption of the engine. 150 percent of the takeoff fuel consumption of the engine.
Fuel boost pumps are operated to provide a positive flow of fuel to the engine. during takeoff only. primarily for fuel transfer to another tank.
A pilot reports that the fuel pressure fluctuates and exceeds the upper limits whenever the throttle is advanced. The most likely cause of the trouble is a ruptured fuel pump relief-valve diaphragm. a sticking fuel pump relief valve. an air leak at the fuel pump relief-valve body.
A fuel strainer or filter must be located between the boost pump and tank outlet. tank outlet and the fuel metering device. boost pump and engine-driven fuel pump.
Fuel pump relief valves designed to compensate for atmospheric pressure variations are known as compensated-flow valves. pressurized-relief valves. balanced-type relief valves.
Fuel lines are kept away from sources of heat, and sharp bends and steep rises are avoided to reduce the possibility of liquid lock. vapor lock. positive lock.
Fuel crossfeed systems are used in aircraft to purge the fuel tanks. jettison fuel in an emergency. maintain aircraft stability.
If an engine equipped with a float-type carburetor backfires or misses when the throttle is advanced, a likely cause is that the float level is too high. main air bleed is clogged. accelerating pump is not operating properly.
A fuel pressure relief valve is required on engine-driven diaphragm-type fuel pumps. engine-driven vane-type fuel pumps. centrifugal fuel boost pumps.
A rotary-vane pump is best described as a positive-displacement pump. variable-displacement pump. boost pump.
Fuel pressure produced by the engine-driven fuel pump is adjusted by the bypass valve adjusting screw. relief valve adjusting screw. engine-driven fuel pump adjusting screw.
Kerosene is used as turbine engine fuel because kerosene has very high volatility which aids in ignition and lubrication. kerosene has more heat energy per gallon and lubricates fuel system components. kerosene does not contain any water.
What are the principal advantages of the duplex fuel nozzle used in many turbine engines? Restricts the amount of fuel flow to a level where more efficient and complete burning of the fuel is achieved. Provides better atomization and uniform flow pattern. Allows a wider range of fuels and filters to be used.
It is necessary to control acceleration and deceleration rates in turbine engines in order to prevent blowout or die-out. prevent overtemperature. prevent friction between turbine wheels and the case due to expansion and contraction.
Which of the following turbine fuel filters has the greatest filtering action of any present day filter type? Micron filter. Plain screen mesh filter. Wafer screen filter.
What is the purpose of the flow divider in a turbine engine duplex fuel nozzle? Allows an alternate flow of fuel if the primary flow clogs or is restricted. Creates the primary and secondary fuel supplies. Provides a flow path for bleed air which aids in the atomization of fuel.
What causes the fuel divider valve to open in a turbine engine duplex fuel nozzle? Fuel pressure. Bleed air after the engine reaches idle RPM. An electrically operated solenoid.
How often should float carburetors be overhauled? At engine overhaul. Annually. At engine change.
What is the final authority for the details of carburetor overhaul? The local FAA safety inspector. The Type Certificate Data Sheets for the engine. The manufacturer's recommendations.
Excessively rich or lean idle mixtures result in too rapid completion of combustion. incomplete combustion. incomplete cylinder scavenging.
Which statement is true regarding proper throttle rigging of an airplane? The throttle stop on the carburetor must be contacted before the stop in the cockpit. The stop in the cockpit must be contacted before the stop on the carburetor. The throttle control is properly adjusted when neither stop makes contact.
What precaution should be taken when putting thread lubricant on a tapered pipe plug in a carburetor float bowl? Put the thread lubricant only on the first thread. Do not use thread lubricant on any carburetor fitting. Engage the first thread of the plug, then put a small amount of lubricant on the second thread and screw the plug in.
Maximum power is normally considered to be developed in a reciprocating engine with a fuel/air mixture ratio of approximately 8:1 12:1 15:1.
A method commonly used to prevent carburetor icing is to preheat the intake air. mix alcohol with the fuel. electrically heat the throttle valve.
Carburetor icing is most severe at air temperatures between 30 and 40°F. high altitudes. low engine temperatures.
Into what part of a reciprocating engine induction system is deicing alcohol normally injected? The supercharger or impeller section. The airstream ahead of the carburetor. The low-pressure area ahead of the throttle valve.
Carburetor icing on an engine equipped with a constant-speed propeller can be detected by a decrease in power output with no change in manifold pressure or RPM. an increase in manifold pressure with a constant RPM. a decrease in manifold pressure with a constant RPM.
What part of an aircraft in flight will begin to accumulate ice before any other? Wing leading edge. Propeller spinner or dome. Carburetor.
Carburetor icing may be eliminated by which of the following methods? Alcohol spray and electrically heated induction duct. Ethylene glycol spray and heated induction air. Alcohol spray and heated induction air.
Where would a carburetor air heater be located in a fuel injection system? At the air intake entrance. None is required. Between the air intake and the venturi.
An increase in manifold pressure when carburetor heat is applied indicates ice was forming in the carburetor. mixture was too lean. overheating of cylinder heads.
During full power output of an unsupercharged engine equipped with a float-type carburetor, in which of the following areas will the highest pressure exist? Venturi. Intake manifold. Carburetor air scoop.
The use of the carburetor air heater when it is not needed causes a very lean mixture. excessive increase in manifold pressure. a decrease in power and possibly detonation.
As manifold pressure increases in a reciprocating engine, the volume of air in the cylinder increases. weight of the fuel/air charge decreases. density of air in the cylinder increases.
Which of the following statements regarding volumetric efficiency of an engine is true? The volumetric efficiency of an engine will remain the same regardless of the amount of throttle opening. It is impossible to exceed 100 percent volumetric efficiency of any engine regardless of the type of supercharger used. It is possible to exceed 100 percent volumetric efficiency of some engines by the use of superchargers of the proper type.
Bootstrapping of a turbocharged engine is indicated by an overboost condition of the engine on takeoff. a transient increase in engine power. a maximum increase in manifold pressure.
Which of the following would be a factor in the failure of an engine to develop full power at takeoff? Improper adjustment of carburetor heat valve control linkage. Excessively rich setting on the idle mixture adjustment. Failure of the economizer valve to remain closed at takeoff throttle setting.
If the turbocharger waste gate is completely closed, none of the exhaust gases are directed through the turbine. the turbocharger is in the OFF position. all the exhaust gases are directed through the turbine.
Boost manifold pressure is generally considered to be any manifold pressure above 14.7 inches Hg. 50 inches Hg. 30 inches Hg.
What is the purpose of the density controller in a turbocharger system? Limits the maximum manifold pressure that can be produced at other than full throttle conditions. Limits the maximum manifold pressure that can be produced by the turbocharger at full throttle. Maintains constant air velocity at the carburetor inlet.
What is the purpose of the rate-of-change controller in a turbocharger system? Limits the maximum manifold pressure that can be produced by the turbocharger at full throttle conditions. Controls the rate at which the turbocharger discharge pressure will increase. Controls the position of the waste gate after the aircraft has reached its critical altitude.
What directly regulates the speed of a turbocharger? Turbine. Waste gate. Throttle.
What is the purpose of a turbocharger system for a small reciprocating aircraft engine? Compresses the air to hold the cabin pressure constant after the aircraft has reached its critical altitude. Maintains constant air velocity in the intake manifold. Compresses air to maintain manifold pressure constant from sea level to the critical altitude of the engine.
What are the three basic regulating components of a sea-level boosted turbocharger system?
1. Exhaust bypass assembly.
2. Compressor assembly.
3. Pump and bearing casing.
4. Density controller.
5. Differential pressure controller. 2, 3, 4. 1, 4, 5. 1, 2, 3.
The differential pressure controller in a turbocharger system reduces bootstrapping during part-throttle operation. positions the waste gate valve for maximum power. provides a constant fuel-to-air ratio.
The purpose of a sonic venturi on a turbocharged engine is to limit the amount of air that can flow from the turbocharger into the cabin for pressurization. increase the amount of air that can flow from the turbocharger into the cabin for pressurization. increase the velocity of the fuel/air charge.
What is used to drive a supercharger? Exhaust gases. Gear train from the crankshaft. Belt drive through a pulley arrangement.
The purpose of a bellmouth compressor inlet is to provide an increased ram air effect at low airspeeds. maximize the aerodynamic efficiency of the inlet. provide an increased pressure drop in the inlet.
What method(s) is/are used to provide clean air to the engines of helicopters and turboprop airplanes that have particle (sand and ice) separators installed? Positive and negative charged areas to attract and/or repel particulates out of the airflow. Air/moisture separators, and 'washing' the air clean utilizing water droplets. Sharp airflow directional change to take advantage of inertia and/or centrifugal force, and filters or engine inlet screens.
The vortex dissipators installed on some turbine-powered aircraft to prevent engine FOD utilize variable inlet guide vanes (IGV) and/or variable first stage fan blades. variable geometry inlet ducts. a stream of engine bleed air blown toward the ground ahead of the engine.
Vortex dissipator systems are generally activated by a landing gear switch. a fuel pressure switch anytime an engine is operating. an engine inlet airflow sensor.
When an engine with a subsonic divergent type inlet duct is running in place at high speed on the ground, the air pressure within the inlet is negative. positive. ambient.
What indications may shift when a turbofan engine anti-icing (bleed air) system is turned on?
3. EPR. 1 and 2. 2 and 3. 1, 2, and 3.
The purpose of an engine/inlet anti-ice system is primarily to remove ice from engine and/or inlet areas. prevent ice formation in engine and/or inlet areas. remove ice from engine and/or inlet areas and prevent ice formation in engine and/or inlet areas.
If carburetor or induction system icing is not present when carburetor heat is applied with no change in the throttle setting, the mixture will become richer. manifold pressure will increase. engine RPM will increase.
When starting an engine equipped with a carburetor air heater, in what position should the heater be placed? Hot. Cold. Neutral.
The application of carburetor heat during engine operation will decrease the weight of the fuel/air charge. decrease the volume of air in the cylinder. increase the density of air in the cylinder.
The application of carburetor heat will have which of the following effects? The manifold pressure will be increased. The mixture will become leaner. The mixture will become richer.
When operating an engine, the application of carburetor heat will have what effect on the fuel/air mixture? Enriching the mixture because the AMC cannot make a correction for increased temperature. Enriching the mixture until the AMC can make a compensation. Leaning the mixture until the AMC can make a compensation.
In addition to causing accelerated wear, dust or sand ingested by a reciprocating engine may also cause silicon fouling of spark plugs. sludge formation. acid formation.
In an airplane equipped with an alternate air system, if the main air duct air filter becomes blocked or clogged, the system will automatically allow warm, unfiltered air to be drawn into the engine. flow of air into the engine will be slowed or cut off unless alternate air is selected. system will automatically allow warm, filtered alternate air to be drawn into the engine.
If a fire starts in the induction system during the engine starting procedure, what should the operator do? Turn off the fuel pump switches. Continue cranking the engine. Turn off the magneto switches.
On small aircraft engines, fuel vaporization may be increased by cooling the air before it enters the engine. circulating the fuel and air mixture through passages in the oil sump. heating the fuel before it enters the carburetor.
The action of a carburetor airscoop is to supply air to the carburetor, but it may also cool the engine. keep fuel lines cool and prevent vapor lock. increase the pressure of the incoming air by ram effect.
A carburetor air pre-heater is not generally used on takeoff unless absolutely necessary because of the loss of power and possible detonation. possibility of induction system overboost. inability of the engine to supply enough heat to make a significant difference.
The pressure between the turbocharger and the throttle valve is called turbocharger boost pressure. induction manifold pressure. upper deck pressure.
Which of the following is a function of the differential pressure controller? It limits the maximum manifold pressure that can be produced by the turbocharger at full throttle conditions. It controls all positions of the waste gate except at fully open position. It controls the position of the waste gate after the aircraft has reached its critical altitude.
The primary purpose of baffles and deflectors installed around cylinders of air-cooled aircraft engines is to create a low pressure area aft of the cylinders. force cooling air into close contact with all parts of the cylinders. increase the volume of air used to cool the engine.
What is the purpose of an augmenter used in some reciprocating engine exhaust systems? To reduce exhaust back pressure. To aid in cooling the engine. To assist in displacing the exhaust gases.
Aircraft reciprocating engine cylinder baffles and deflectors should be repaired as required to prevent loss of power. fin area. cooling.
Cracks in cooling fins that do not extend into the cylinder head should be left alone and monitored. may be repaired by removing the affected area and contour filing within limits. may be repaired by adding a stiffener.
Which of the following should a mechanic consult to determine the maximum amount of cylinder cooling fin that could be removed when cracks are found? AC 43.13-1A. Engine manufacturer's service or overhaul manual. Engine structure repair manual.
A bent cooling fin on an aluminum cylinder head should be sawed off and filed smooth. left alone if no crack has formed. straightened out as much as possible without breaking.
Where are cooling fins usually located on air-cooled engines? Exhaust side of the cylinder head, inside the pistons, and connecting rods. Cylinder head, cylinder walls, and inside the piston. Cylinder head, cylinder barrel, and inside the piston.
How do cowl flaps aid in cooling a horizontally opposed aircraft engine? Recirculates air through the engine cylinders. Directs air through the engine cylinders. Controls the amount of air flowing around the cylinders.
The position of the cowl flaps during normal cruise flight conditions is closed. open. neutral.
Generally, a small crack just started in a cylinder baffle requires repair by reinforcing, such as installation of a doubler over the area. requires no action unless it grows or is branched into two cracks. may be stop drilled.
Which of the following assists in removing heat from the metal walls and fins of an air-cooled cylinder assembly? An intercooler system. A baffle and cowl arrangement. An engine induction system.
During ground operation of an engine, the cowl flaps should be in what position? Fully closed. Fully open. Opened according to ambient conditions.
The component(s) in a turbine engine that operate(s) at the highest temperatures is/are the first stage turbine nozzle guide vanes. turbine disks. exhaust cone.
During an operational check of an electrically powered aircraft engine cowl flap system, the motor fails to operate. Which of the following is the first to be checked? Flap actuator motor circuit breaker. Flap actuator control switch. Flap actuator motor.
(1) Some aircraft exhaust systems include an augmenter system to draw additional air over the engine for cooling.
(2) Augmenter systems are used to create a low pressure area at the lower rear of the aircraft engine cowling.
Regarding the above statements, only No. 1 is true. both No. 1 and No. 2 are true. only No. 2 is true.
Which of the following defects would likely cause a hot spot on a reciprocating engine cylinder? Too much cooling fin area broken off. A cracked cylinder baffle. Cowling air seal leakage.
What part of an air-cooled cylinder assembly has the greatest fin area per square inch? Cylinder barrel. Rear of the cylinder head. Exhaust valve port.
Reciprocating engines used in helicopters are cooled by the downdraft from the main rotor. a fan mounted on the engine. blast tubes on either side of the engine mount.
The greatest portion of heat generated by combustion in a typical aircraft reciprocating engine is converted into useful power. carried out with the exhaust gases. dissipated through the cylinder walls and heads.
A broken cooling fin on a cylinder head is cause for rejection of the head. may be filed to smooth contours if damage and/or repair limits are not exceeded. should be left alone.
An engine becomes overheated due to excessive taxiing or improper ground runup. Prior to shutdown, operation must continue until cylinders have cooled, by running engine at low RPM with oil dilution system activated. idle RPM. high RPM with mixture control in rich position.
Cylinder head temperatures are measured by means of an indicator and a resistance bulb sensing device. wheatstone bridge sensing device. thermocouple sensing device.
High cylinder head temperatures are likely to result from a very lean mixture at high power settings. fouled spark plugs. a very rich mixture at high power settings.
The purpose of an intercooler when used with a turbocharger is to cool the exhaust gases before they come in contact with the turbo drive. turbocharger bearings. air entering the carburetor from the turbocharger.
Prolonged idling of an engine will usually result in excessive cylinder head temperatures. increased oil consumption. foreign material buildup on spark plugs.
The most common method and generally the best conduction of heat from the inside of a cylinder barrel to the cooling air is accomplished by machining fins directly on the outside of the barrel. shrinking on a jacket or muff of aluminum cooling fins around a steel cylinder sleeve. machining fins directly on the outside of the barrel and shrinking on a jacket or muff of aluminum cooling fins around a steel cylinder sleeve (on different areas of the barrel).
What is the function of a blast tube as found on aircraft engines? A means of cooling the engine by utilizing the propeller backwash. A tube used to load a cartridge starter. A device to cool an engine accessory.
Which statement is true regarding the air passing through the combustion section of a jet engine? Most is used for engine cooling. Most is used to support combustion. A small percentage is frequently bled off at this point to be used for air-conditioning and/or other pneumatic powered systems.
Which of the following results in a decrease in volumetric efficiency? Cylinder head temperature too low. Part-throttle operation. Short intake pipes of large diameter.
The undersides of pistons are frequently finned. The principal reason is to provide sludge chambers and sediment traps. provide for greater heat transfer to the engine oil. support ring grooves and piston pins.
What is the position of the cowl flaps during engine starting and warmup operations under normal conditions? Full open at all times. Full closed at all times. Open for starting, closed for warmup.
Increased engine heat will cause volumetric efficiency to remain the same. decrease. increase.
Why is high nickel chromium steel used in many exhaust systems? High heat conductivity and flexibility. Corrosion resistance and low expansion coefficient. Corrosion resistance and high heat conductivity.
Reciprocating engine exhaust system designs commonly used to provide for ease of installation and/or allow for expansion and contraction, may include the use of
1. spring loaded ball/flexible joints.
2. slip joints.
4. flexible metal tubing. 1, 2, 3, and/or 4. 1, 2, and/or 4. 1, 2, and/or 3.
One source commonly used for carburetor air heat is turbocharger heated air. alternate air heat. exhaust gases.
The hot section of a turbine engine is particularly susceptible to which of the following kind of damage? Galling. Pitting. Cracking.
What is the purpose of a slip joint in an exhaust collector ring? It aids in alignment and absorbs expansion. It reduces vibration and increases cooling. It permits the collector ring to be installed in one piece.
Sodium-filled valves are advantageous to an aviation engine because they are lighter. dampen valve impact shocks. dissipate heat well.
What type of nuts are used to hold an exhaust system to the cylinders? Brass or heat-resistant nuts. High-temperature fiber self-locking nuts. High-temperature aluminum self-locking nuts.
Repair of exhaust system components is impossible because the material cannot be identified. must be accomplished by the component manufacturer. is not recommended to be accomplished in the field.
On turbojet powered airplanes, thrust reversers are capable of producing between 35 and 50 percent of the rated thrust in the reverse direction. 35 and 75 percent of the rated thrust in the reverse direction. 35 and 65 percent of the rated thrust in the reverse direction.
On an aircraft that utilizes an exhaust heat exchanger as a source of cabin heat, how should the exhaust system be inspected? X-rayed to detect any cracks. Hydrostatically tested. With the heater air shroud removed.
How should ceramic-coated exhaust components be cleaned? With alkali. By degreasing. By mechanical means.
Which of the following indicates that a combustion chamber of a jet engine is not operating properly? Clam shells stick in thrust reverse position. Hot spots on the tail cone. Warping of the exhaust duct liner.
Select a characteristic of a good weld on exhaust stacks. The weld should be built up 1/8 inch. Porousness or projecting globules should show in the weld. The weld should taper off smoothly into the base metal.
How do the turbines which are driven by the exhaust gases of a turbo-compound engine contribute to total engine power output? By driving the crankshaft through suitable couplings. By driving the supercharger, thus relieving the engine of the supercharging load. By converting the latent heat energy of the exhaust gases into thrust by collecting and accelerating them.
How should corrosion-resistant steel parts such as exhaust collectors be blast cleaned? Use steel grit which has not previously been used on soft iron. Use super fine granite grit. Use sand which has not previously been used on iron or steel.
Power recovery turbines used on some reciprocating engines are driven by the exhaust gas pressure. crankshaft. velocity of the exhaust gases.
Reciprocating engine exhaust systems that have repairs or sloppy weld beads which protrude internally are unacceptable because they cause base metal fatigue. localized cracks. local hot spots.
Ball joints in reciprocating engine exhaust systems should be tight enough to prevent any movement. disassembled and the seals replaced every engine change. loose enough to permit some movement.
All of the following are recommended markers for reciprocating engine exhaust systems except India ink. lead pencil. Prussian blue.
How are combustion liner walls cooled in a gas turbine engine? By secondary air flowing through the combustion chamber. By the pattern of holes and louvers cut in the diffuser section. By bleed air vented from the engine air inlet.
Augmenter tubes are part of which reciprocating engine system? Induction. Exhaust. Fuel.
Dislodged internal muffler baffles on a small reciprocating engine may cause excessive exhaust back pressure. an engine over-speed problem. high oil consumption.
What is the purpose of an exhaust outlet guard on a small reciprocating engine? To prevent dislodged muffler baffles from obstructing the muffler outlet. To reduce spark exit. To shield adjacent components from excessive heat.
What could be a result of undetected exhaust system leaks in a reciprocating engine powered airplane? Pilot/passenger incapacitation caused by carbon monoxide entering the cabin. A rough-running engine with increased fuel consumption. Too low exhaust back pressure resulting in the desired power settings not being attained.
How may reciprocating engine exhaust system leaks be detected? An exhaust trail aft of the tailpipe on the airplane exterior. Fluctuating manifold pressure indication. Signs of exhaust soot inside cowling and on adjacent components.
Compared to normally aspirated engines, turbocharged engine exhaust systems operate at similar temperatures and higher pressures. higher temperatures and higher pressures. similar temperatures and pressures.
Most exhaust system failures result from thermal fatigue cracking in the areas of stress concentration. This condition is usually caused by the drastic temperature change which is encountered at altitude. improper welding techniques during manufacture. the high temperatures at which the exhaust system operates.
Thrust reversers utilizing a pneumatic actuating system usually receive operating pressure from the engine bleed air system. an on board hydraulic or electrical powered compressor. high pressure air reservoirs.
Operating thrust reversers at low ground speeds can sometimes cause
1. sand or other foreign object ingestion.
2. hot gas re-ingestion.
3. compressor stalls. 1, 2, and 3. 1 and 2. 2 and 3.
Engines using cold stream, or both cold and hot stream reversing include high bypass turbofans. turbojets. turbojets with afterburner.
The purpose of cascade vanes in a thrust reversing system is to form a solid blocking door in the jet exhaust path. turn the exhaust gases forward just after exiting the exhaust nozzle. turn to a forward direction the fan and/or hot exhaust gases that have been blocked from exiting through the exhaust nozzle.
Turbojet and turbofan thrust reverser systems are generally powered by
1. fuel pressure.
3. hydraulic pressure.
4. pneumatic pressure. 1, 3, and 4. 2, 3, and 4. 1, 2 and 3.
The rearward thrust capability of an engine with the thrust reverser system deployed is less than its forward capability. greater than its forward capability. equal to its forward capability.
Which of the following statements is true regarding thrust reverser systems? The reverser system must be able to withstand high temperatures, be mechanically strong, relatively light in weight, and reliable. Engine thrust reversers on the aircraft usually will operate independently of each other. Mechanical blockage system design permits a deployment position aft of the exhaust nozzle only.
What is the proper operating sequence when using thrust reversers to slow an aircraft after landing? Advance thrust levers up to takeoff position as conditions require, select thrust reverse, de-select thrust reverser, retard thrust levers to ground idle. Retard thrust levers to ground idle, raise thrust reverser levers as required, and retard thrust reverser levers to ground idle. Select thrust reverse, advance thrust reverser levers no higher than 75 percent N(1), and retard thrust reverser levers to idle at approximately normal taxi speed.
How is aircraft electrical power for propeller deicer systems transferred from the engine to the propeller hub assembly? By slip rings and segment plates. By slip rings and brushes. By flexible electrical connectors.
How is anti-icing fluid ejected from the slinger ring on a propeller? By pump pressure. By centripetal force. By centrifugal force.
On most reciprocating multiengine aircraft, automatic propeller synchronization is accomplished through the actuation of the throttle levers. propeller governors. propeller control levers.
Propeller fluid anti-icing systems generally use which of the following? Ethylene glycol. Isopropyl alcohol. Ethyl alcohol.
What is a function of the automatic propeller synchronizing system on multiengine aircraft? To control the tip speed of all propellers. To control engine RPM and reduce vibration. To control the power output of all engines.
Ice formation on a propeller blade will produce unbalance and vibration. increase thrust and drag. cause a change in blade angle.
What unit in the propeller anti-icing system controls the output of the pump? Pressure relief valve. Rheostat. Cycling timer.
Proper operation of electric deicing boots on individual propeller blades may best be determined by feeling the sequence of boot heating and have an assistant observe the loadmeter indications. observing the ammeter or loadmeter for current flow. feeling the boots to see if they are heating.
A propeller synchrophasing system allows a pilot to reduce noise and vibration by adjusting the phase angle between the propellers on an aircraft's engines. adjusting the plane of rotation of all propellers. setting the pitch angle of all propellers exactly the same.
Which of the following determines oil and grease specifications for lubrication of propellers? Lubricant manufacturer's instructions. Engine manufacturer's instructions. Propeller manufacturer's instructions.
Grease used in aircraft propellers reduces the frictional resistance of moving parts and is easily molded into any form under pressure. This statement defines antifriction and plasticity characteristics of grease. antifriction and chemical stability of grease. viscosity and melting point of grease.
What type of imbalance will cause a two-blade propeller to have a persistent tendency to come to rest in a horizontal position (with the blades parallel to the ground) while being checked on a propeller balancing beam? Vertical. Horizontal. Harmonic.
What is the purpose of an arbor used in balancing a propeller? To support the propeller on the balance knives. To level the balance stand. To mark the propeller blades where weights are to be attached.
If a blade of a particular metal propeller is shortened because of damage to the tip, the remaining blade(s) must be reset (blade angle) to compensate for the shortened blade. returned to the manufacturer for alteration. reduced to conform with the shortened blade.
The application of more protective coating on one blade than the other when refinishing a wood propeller has little or no effect on operating characteristics. should never be done. may be necessary to achieve final balancing.
Apparent engine roughness is often a result of propeller unbalance. The effect of an unbalanced propeller will usually be approximately the same at all speeds. greater at low RPM. greater at high RPM.
Which of the following is used to correct horizontal unbalance of a wood propeller? Brass screws. Shellac. Solder.
Propeller aerodynamic (thrust) imbalance can be largely eliminated by correct blade contouring and angle setting. static balancing. keeping the propeller blades within the same plane of rotation.
A powerplant using a hydraulically controlled constant-speed propeller is operating within the propeller's constant-speed range at a fixed throttle setting. If the tension of the propeller governor control spring (speeder spring) is reduced by movement of the cockpit propeller control, the propeller blade angle will increase, engine manifold pressure will increase, and engine RPM will decrease. decrease, engine manifold pressure will increase, and engine RPM will decrease. decrease, engine manifold pressure will decrease, and engine RPM will increase.
Why is the pulley stop screw on a propeller governor adjustable? To limit the maximum engine speed during takeoff. To maintain the proper blade angle for cruising. To limit the maximum propeller pitch for takeoff.
During engine operation at speeds lower than those for which the constant-speed propeller control can govern in the INCREASE RPM position, the propeller will remain in the full HIGH PITCH position. maintain engine RPM in the normal manner until the HIGH PITCH stop is reached. remain in the full LOW PITCH position.
When engine power is increased, the constant-speed propeller tries to function so that it will maintain the RPM, decrease the blade angle, and maintain a low angle of attack. increase the RPM, decrease the blade angle, and maintain a low angle of attack. maintain the RPM, increase the blade angle, and maintain a low angle of attack.
The propeller governor controls the oil to and from the pitch changing mechanism. spring tension on the boost pump speeder spring. linkage and counterweights from moving in and out.
During the on-speed condition of a propeller, the centrifugal force acting on the governor flyweights is greater than the tension of the speeder spring. tension on the speeder spring is less than the centrifugal force acting on the governor flyweights. centrifugal force of the governor flyweights is equal to the speeder spring force.
What actuates the pilot valve in the governor of a constant-speed propeller? Engine oil pressure. Governor flyweights. Governor pump oil pressure.
What action takes place when the cockpit control lever for a hydromatic, constant-speed propeller is actuated? Compression of the speeder spring is changed. The governor booster pump pressure is varied. The governor bypass valve is positioned to direct oil pressure to the propeller dome.
What will happen to the propeller blade angle and the engine RPM if the tension on the propeller governor control spring (speeder spring) is increased? Blade angle will decrease and RPM will decrease. Blade angle will increase and RPM will decrease. Blade angle will decrease and RPM will increase.
How is the speed of a constant-speed propeller changed in flight? By varying the output of the governor booster pump. By advancing or retarding the throttle. By changing the load tension against the flyweights in the governor.
When the centrifugal force acting on the propeller governor flyweights overcomes the tension on the speeder spring, a propeller is in what speed condition? On speed. Underspeed. Overspeed.
What operational force causes the greatest stress on a propeller? Aerodynamic twisting force. Centrifugal force. Thrust bending force.
What operational force tends to increase propeller blade angle? Centrifugal twisting force. Aerodynamic twisting force. Thrust bending force.
How is a propeller controlled in a large aircraft with a turboprop installation? Independently of the engine. By varying the engine RPM except for feathering and reversing. By the engine power lever.
How does the aerodynamic twisting force affect operating propeller blades? It tends to turn the blades to a high blade angle. It tends to bend the blades forward. It tends to turn the blades to a low blade angle.
Which of the following best describes the blade movement of a propeller that is in the high RPM position when reversing action is begun? Low pitch directly to reverse pitch. Low pitch through high pitch to reverse pitch. Low pitch through feather position to reverse pitch.
Propellers exposed to salt spray should be flushed with engine oil. fresh water. soapy water.
How can a steel propeller hub be tested for cracks? By anodizing. By magnetic particle inspection. By etching.
Which of the following functions requires the use of a propeller blade station? Measuring blade angle. Indexing blades. Propeller balancing.
The propeller blade angle is defined as the acute angle between the airfoil section chord line (at the blade reference station) and which of the following? The plane of rotation. The relative wind. The axis of blade rotation during pitch change.
During which of the following conditions of flight will the blade pitch angle of a constant-speed propeller be the greatest? Approach to landing. Climb following takeoff. High-speed, high-altitude cruising flight.
The actual distance a propeller moves forward through the air during one revolution is known as the effective pitch. geometric pitch. relative pitch.
The pitch-changing mechanism of the hydromatic propeller is lubricated by the pitch-changing oil. using an approved-type grease in a grease gun at intervals prescribed by the propeller manufacturer. thoroughly greasing, necessary only during propeller overhaul.
What is the result of moving the throttle on a reciprocating engine when the propeller is in the constant-speed range with the engine developing cruise power? Opening the throttle will cause an increase in blade angle. The RPM will vary directly with any movement of the throttle. Movement of the throttle will not affect the blade angle.
Propeller blade stations are measured from the index mark on the blade shank. hub centerline. blade base.
The thrust produced by a rotating propeller is a result of an area of low pressure behind the propeller blades. an area of decreased pressure immediately in front of the propeller blades. the angle of relative wind and rotational velocity of the propeller.
Why is a constant-speed counterweight propeller normally placed in full HIGH PITCH position before the engine is stopped? To prevent exposure and corrosion of the pitch changing mechanism. To prevent hydraulic lock of the piston when the oil cools. To prevent overheating of the engine during the next start.
The low pitch stop on a constant-speed propeller is usually set so that the engine will turn at its rated takeoff RPM at sea level when the throttle is opened to allowable takeoff manifold pressure. maximum allowable engine RPM cannot be exceeded with any combination of manifold pressure, altitude, or forward speed. the limiting engine manifold pressure cannot be exceeded with any combination of throttle opening, altitude, or forward speed.
The angle-of-attack of a rotating propeller blade is measured between the blade chord or face and which of the following? Plane of blade rotation. Full low-pitch blade angle. Relative airstream.
The centrifugal twisting moment of an operating propeller tends to increase the pitch angle. reduce the pitch angle. bend the blades in the direction of rotation.
Which of the following is identified as the cambered or curved side of a propeller blade, corresponding to the upper surface of a wing airfoil section? Blade back. Blade chord. Blade face.
Which of the following best describes the blade movement of a full-feathering, constant-speed propeller that is in the LOW RPM position when the feathering action is begun? High pitch through low pitch to feather position. High pitch directly to feather position. Low pitch through high pitch to feather position.
The holding coil on a hydromatic propeller feathering button switch holds a solenoid relay closed that applies power to the propeller governor. dome feathering mechanism. feathering pump motor.
What is the primary purpose of the metal tipping which covers the blade tips and extends along the leading edge of each wood propeller blade? To increase the lateral strength of the blade. To prevent impact damage to the tip and leading edge of the blade. To increase the longitudinal strength of the blade.
Blade angle is an angle formed by a line perpendicular to the crankshaft and a line formed by the relative wind. chord of the blade. blade face.
Propeller blade station numbers increase from hub center line to tip. tip to hub center line. blade shank butt to tip.
The aerodynamic force acting on a rotating propeller blade operating at a normal pitch angle tends to reduce the pitch angle. increase the pitch angle. bend the blades rearward in the line of flight.
Which of the following forces or combination of forces operates to move the blades of a constant-speed counterweight-type propeller to the HIGH PITCH position? Engine oil pressure acting on the propeller piston-cylinder arrangement and centrifugal force acting on the counterweights. Centrifugal force acting on the counterweights. Prop governor oil pressure acting on the propeller piston-cylinder arrangement.
The purpose of permanently sealing and partially filling some models of McCauley propeller hubs with dyed oil is to provide an always clean separate lubrication of the internal parts. dampen pressure surges and prevent too rapid changes in propeller blade angle. make the location of cracks readily apparent.
Which of the following best describes the blade movement of a feathering propeller that is in the HIGH RPM position when the feathering action is begun? High pitch through low pitch to feather position. Low pitch through reverse pitch to feather position. Low pitch through high pitch to feather position.
The blade angle of a fixed-pitch propeller is greatest at the tip. is smallest at the tip. increases in proportion to the distance each section is from the hub.
During operational check of an aircraft using hydromatic full-feathering propellers, the following observations are made:
The feather button, after being pushed, remains depressed until the feather cycle is complete, then opens.
When unfeathering, it is necessary to manually hold the button down until unfeathering is accomplished. Both feather cycle and unfeather cycle are functioning properly. Both feather and unfeather cycles indicate malfunctions. The feather cycle is correct. The unfeather cycle indicates a malfunction.
Inspection of propeller blades by dye-penetrant inspection is accomplished to detect fatigue failure. material de-bond. warpage.
What controls the constant-speed range of a constant-speed propeller? Engine RPM. Angle of climb and descent with accompanying changes in airspeed. The mechanical limits in the propeller pitch range.
For takeoff, a constant-speed propeller is normally set in the HIGH PITCH, high RPM position. HIGH PITCH, low RPM position. LOW PITCH, high RPM position.
Where are the high and low pitch stops of a Hamilton Standard constant-speed or two-position counterweight propeller located? In the hub and blade assembly. In the counterweight assembly. In the dome assembly.
Which of the following statements about constant-speed counterweight propellers is also true when referring to two-position counterweight propellers? Blade angle changes are accomplished by the use of two forces, one hydraulic and the other centrifugal. Since an infinite number of blade angle positions are possible during flight, propeller efficiency is greatly improved. The pilot selects the RPM and the propeller changes pitch to maintain the selected RPM.
Most engine-propeller combinations have one or more critical ranges within which continuous operation is not permitted. Critical ranges are established to avoid severe propeller vibration. low or negative thrust conditions. inefficient propeller pitch angles.
Which of the following defects is cause for rejection of wood propellers? Solder missing from screw heads securing metal tipping. An oversize hub or bolthole, or elongated boltholes. No protective coating on propeller.
An aircraft's propeller system beta range is used to produce zero or negative thrust. is used to achieve maximum thrust during takeoff. refers to the most fuel efficient pitch range to use at a given engine RPM.
The primary purpose of a cuff on a propeller is to distribute anti-icing fluid. strengthen the propeller. increase the flow of cooling air to the engine nacelle.
The purpose of a three-way propeller valve is to direct oil from the engine oil system to the propeller cylinder. direct oil from the engine through the governor to the propeller. permit constant-speed operation of the propeller.
The primary purpose of a propeller is to create lift on the fixed airfoils of an aircraft. change engine horsepower to thrust. provide static and dynamic stability of an aircraft in flight.
A constant-speed propeller provides maximum efficiency by increasing blade pitch as the aircraft speed decreases. adjusting blade angle for most conditions encountered in flight. increasing the lift coefficient of the blade.
The centrifugal twisting force acting on a propeller blade is greater than the aerodynamic twisting force and tends to move the blade to a higher angle. less than the aerodynamic twisting force and tends to move the blade to a lower angle. greater than the aerodynamic twisting force and tends to move the blade to a lower angle.
Geometric pitch of a propeller is defined as the effective pitch minus slippage. effective pitch plus slippage. angle between the blade chord and the plane of rotation.
Propeller blade angle is the angle between the chord of the blade and the relative wind. relative wind and the rotational plane of the propeller. chord of the blade and the rotational plane of the propeller.
What operational force causes propeller blade tips to lag in the opposite direction of rotation? Thrust-bending force. Aerodynamic-twisting force. Torque-bending force.
What operational force tends to bend the propeller blades forward at the tip? Torque-bending force. Centrifugal-twisting force. Thrust-bending force.
What are the rotational speed and blade pitch angle requirements of a constant-speed propeller during takeoff? Low-speed and high-pitch angle. High-speed and low-pitch angle. High-speed and high-pitch angle.
(1) A mechanic certificate with a powerplant rating authorizes the holder to repair deep scars, nicks, and dents on aluminum propeller blades.
(2) A mechanic certificate with a powerplant rating authorizes the holder to perform minor straightening of steel propeller blades.
Regarding the above statements, only No. 1 is true. both No. 1 and No. 2 are true. neither No. 1 nor No. 2 is true.
(1) During takeoff, propeller thrust (pull) is greatest if the blade angle of attack is low and the engine power setting is high.
(2) With the aircraft stationary, propeller thrust is greatest if the blade angle of attack is high and the engine power setting is high.
Regarding the above statements, only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
Longitudinal (fore and aft) clearance of constant-speed propeller blades or cuffs must be at least 1/2 inch (12.7 mm) between propeller parts and stationary parts of the aircraft. This clearance is with the propeller blades at takeoff pitch (maximum thrust) angle. feathered or in the most critical pitch configuration. at the lowest pitch angle.
Constant-speed non-feathering McCauley, Hartzell, and other propellers of similar design without counterweights increase pitch angle using oil pressure. spring pressure. centrifugal twisting moment.
Counterweights on constant-speed propellers are generally used to aid in increasing blade angle. decreasing blade angle. unfeathering the propellers.
When lubricating a Hartzell propeller blade with grease, to prevent damage to the blade seals, the service manual may recommend on some models to pump grease into both zerk fittings for the blade simultaneously. remove the seals prior to greasing and reinstall them afterwards. remove one of the two zerk fittings for the blade and grease the blade through the remaining fitting.
The primary purpose of a feathering propeller is to prevent further engine damage when an engine fails in flight. prevent propeller damage when an engine fails in flight. eliminate the drag created by a windmilling propeller when an engine fails in flight.
What normally prevents a Hartzell Compact propeller from going to feather when the engine is shut down on the ground? Propeller cylinder air pressure. A latch mechanism composed of springs and lock pins. Accumulator provided oil pressure.
When running-up an engine and testing a newly installed hydromatic propeller, it is necessary to exercise the propeller by moving the governor control through its entire travel several times to seat the blades fully against the low pitch stop. free the dome of any entrapped air. test the maximum RPM setting of the governor.
Which of the following occurs to cause front cone bottoming during propeller installation? The front cone becomes bottomed in the front propeller hub cone seat before the rear propeller hub cone seat has engaged the rear cone. The front cone enters the front propeller hub cone seat at an angle causing the propeller retaining nut to appear tight when it is only partially tightened. The front cone contacts the ends of the shaft splines, preventing the front and rear cones from being tightened against the cone seats in the propeller hub.
What is indicated when the front cone bottoms while installing a propeller? Propeller-dome combination is incorrect. Blade angles are incorrect. Rear cone should be moved forward.
How is the oil pressure delivery on a hydromatic propeller normally stopped after the blades have reached their full-feathered position? Pulling out the feathering push button. Electric cutout pressure switch. Stop lugs in the teeth of the rotating cam.
The primary purpose of the front and rear cones for propellers that are installed on splined shafts is to position the propeller hub on the splined shaft. prevent metal-to-metal contact between the propeller and the splined shaft. reduce stresses between the splines of the propeller and the splines of the shaft.
Which of the following statements concerning the installation of a new fixed-pitch wood propeller is true? Inspect the bolts for proper torque after every 50 hours and annual inspection. Install and tighten the bolts to the proper torque during installation; no inspection interval after that.q Inspect the bolts for proper torque after the first flight and after the first 25 hours of flying.
If propeller cones or hub cone seats show evidence of galling and wear, the most likely cause is the pitch change stops were located incorrectly, causing the cone seats to act as the high pitch stop. the propeller retaining nut was not tight enough during previous operation. the front cone was not fully bottomed against the crankshaft splines during installation.
On aircraft equipped with hydraulically operated constant-speed propellers, all ignition and magneto checking is done with the propeller in which position? High RPM. Low RPM. High pitch range.
Oil leakage around the rear cone of a hydromatic propeller usually indicates a defective piston gasket. spider-shaft oil seal. dome-barrel oil seal.
Maximum taper contact between crankshaft and propeller hub is determined by using bearing blue color transfer. a micrometer. a surface gauge.
Propeller blade tracking is the process of determining the plane of rotation of the propeller with respect to the aircraft longitudinal axis. that the blade angles are within the specified tolerance of each other. the positions of the tips of the propeller blades relative to each other.
What is the basic purpose of the three small holes (No. 60 drill) in the tipping of wood propeller blades? To provide a means for inserting balancing shot when necessary. To provide a means for periodically impregnating the blade with preservation materials. To allow the moisture which may collect between the tipping and the wood to escape (vent the tipping).
A fixed-pitch wooden propeller that has been properly installed and the attachment bolts properly torqued exceeds the out-of-track allowance by 1/16 inch. The excessive out-of-track condition may be corrected by slightly overtightening the attachment bolts adjacent to the most forward blade. discarding the propeller since out-of-track conditions cannot be corrected. placing shims between the inner flange and the propeller.
Manually feathering a hydromechanical propeller means to block governor oil pressure to the cylinder of the propeller. port governor oil pressure to the cylinder of the propeller. port governor oil pressure from the cylinder of the propeller.
In what position is the constant-speed propeller control placed to check the magnetos? Full decrease, low propeller blade pitch angle. Full increase, high propeller blade pitch angle. Full increase, low propeller blade pitch angle.
If a flanged propeller shaft has dowel pins install the propeller so that the blades are positioned for hand propping. the propeller can only be installed in a given position. the front cone should be checked for bottoming against the pins.
Repairs of aluminum alloy adjustable pitch propellers are not permitted to be made on which of the following propeller blade areas? Shank. Face. Back.
Which of the following methods is used to straighten a bent aluminum propeller blade that is within repairable limits? Careful heating to accomplish straightening, followed by heat treatment to restore original strength. Either hot or cold straightening, depending on the location and severity of damage. Cold straightening only.
It is important that nicks in aluminum alloy propeller blades be repaired as soon as possible in order to maintain equal aerodynamic characteristics between the blades. eliminate stress concentration points. equalize the centrifugal loads between the blades.
Generally, unless otherwise specified by the manufacturer, repairs of nicks, scratches, gouges, etc. on aluminum propeller blades must be made parallel to the length of the blade. perpendicular to the blade axis. so as to return the damaged area to the original dimensions.
Minor surface damage located in a repairable area, but not on the leading or trailing edges of aluminum blades, may be repaired by first filing with a riffle file. filing with a half round or flat file. rough sanding and applying a proper filler.
After proper removal of aluminum blade damage, the affected surface should be polished with fine steel wool or scotch-brite. very fine sandpaper or crocus cloth. soapstone or wire brush.
When preparing a propeller blade for inspection it should be cleaned with mild soap and water. steel wool. methyl ethyl ketone.
What method would be used to inspect an aluminum propeller blade when a crack is suspected? Use a bright light. Magnetic particle. Dye-penetrant.
Removal of propeller blade tips within Type Certificate Data Sheet limits when correcting a defect is a major alteration. a major repair. permitted under the privileges and limitations of a powerplant rating.
Surface treatment to counter the effects of dye-penetrant inspection on a propeller is accomplished by washing off with solvent. wiping with alcohol. rinse the blade in alodine solution.
One of the advantages of inspecting an aluminum propeller utilizing dye-penetrant inspection procedure is that defects just below the surface are indicated. it shows whether visible lines and other marks are actually cracks rather than scratches. it indicates overspeed condition.
The primary reason for careful inspection and prompt repairing of minor surface defects such as scratches, nicks, gouges, etc. on aluminum alloy propellers is to prevent corrosion. unbalanced aerodynamics. fatigue failure.
Which of the following generally renders an aluminum alloy propeller unrepairable? Blade face surface damage. Leading or trailing edge damage. Transverse cracks of any size.
Cold straightening a bent aluminum propeller blade may be accomplished by the holder of a mechanic certificate with a powerplant rating. an appropriately rated repair station or the manufacturer. a person working under the supervision of the holder of a mechanic certificate with both airframe and powerplant ratings.
How does the propeller overspeed governor on a turboprop engine decrease propeller RPM? When oil pressure is decreased, the return spring and counterweights force the oil out of the servo piston. As oil pressure increases, the servo piston is pushed forward, and the feather spring is compressed. When oil pressure is increased, the return spring and counterweights force the oil out of the servo piston.
Which of the following defects is cause for rejection of wood propellers? Dye penetrant inspection failure. Bonding or separation of the trailing edge of the propeller blade. Delamination found by conducting a tap test.
When lubricating a newly overhauled steel hub propeller, you should lubricate the propeller after 10 hours of operation. at the next 100-hour inspection. after one to two hours of operation.
Frequently, an aircraft's auxiliary power unit (APU) generator is identical to the engine-driven generators. supplements the aircraft's engine-driven generators during peak loads. has a higher load capacity than the engine-driven generators.
Fuel is normally supplied to an APU from the APU independent fuel tank. airplane's header fuel tank. airplane's main fuel tank.
An APU is usually rotated during start by a turbine impingement system. a pneumatic starter. an electric starter.
The function of an APU air inlet plenum is to increase the velocity of the air before entering the compressor. decrease the pressure of the air before entering the compressor. stabilize the pressure of the air before it enters the compressor.
When in operation, the speed of an APU is controlled by a cockpit power lever. remains at idle and automatically accelerates to rated speed when placed under load. remains at or near rated speed regardless of the load condition.
Generally, when maximum APU shaft output power is being used in conjunction with pneumatic power pneumatic loading will be automatically modulated to maintain a safe EGT. electrical loading will be automatically modulated to maintain a safe EGT. temperature limits and loads must be carefully monitored by the operator to maintain a safe EGT.
When necessary, APU engine cooling before shutdown may be accomplished by unloading the generator(s). closing the bleed air valve. opening the bleed air valve.
Usually, most of the load placed on an APU occurs when an electrical load is placed on the generator(s). the bleed air valve is opened. the bleed air valve is closed.
Fuel scheduling during APU start and under varying pneumatic bleed and electrical loads is maintained manually through power control lever position. automatically by the APU fuel control system. automatically by an aircraft main engine fuel control unit.
On APU's equipped with a free turbine and load compressor, the primary function of the load compressor is to provide air for combustion and cooling in the engine gas path. provide bleed air for aircraft pneumatic systems. supply the turning force for operation of the APU generator(s).