Module 14

From where is manifold pressure taken on a supercharged engine?. Between the carburetor and the supercharger. Between the supercharger and the throttle. Between the carburetor and the induction ports.

on a gas turbine engine, what is the fan driven by?. HP turbine. LP turbine. IP turbine.

What is an engine stage?. One rotor plus one stator. One IGV and one rotor. One compressor rotor and one nozzle guide vane.

The air data input to the FADEC fails. The result will be. a lack of flight data. uncorrected data from hard wired analogue sensors is utilized. the FADEC reverts to the failsafe mode.

Torque measurement is taken from the. free turbine shaft. reduction gearbox. prop shaft.

A FADEC system consists of. HMU, sensors and an EEC. HMU, ADC and sensors. EEC, ADC and sensors.

What power supply is required for a thermocouple system to work?. Direct current. Alternating current. Neither of the above.

In a 24 thermocouple system, one thermocouple goes open circuit. What error is detected at the indicator?. None. No indication. Gauge freezes at last known reading.

In a thermocouple temperature sensing system, what is the purpose of the compensating resistor?. To correct for varying ambient temperatures at the hot junction. To correct for varying ambient temperatures at the cold junction. To standardize the reading for different engine types.

In a dive, with the throttles fixed, the EPR will. increase. decrease. not change.

How is the N1 and N2 measured on a triple spool engine?. Pulse type speed probes. Tachometer connected to the external gearbox. Tachometer connected to the internal gearbox.

A twin spool engine has. one turbine on one shaft. two turbines on one shaft. two turbines on two shafts.

A free turbine aircraft engine is most likely to be used on a. high bypass engine. a direct coupled engine. a helicopter engine.

Propeller speed is measured from. a slip ring pulse probe. a tachometer on the LP turbine shaft. a pulse probe at the engine side of the reduction gear.

Propeller torque is analogous to. engine RPM. shaft horsepower. propeller RPM.

How is power indicated on a fixed pitch propeller?. RPM gauge. Torque gauge. Horsepower gauge.

What are the units of manifold pressure on a normally aspirated engine?. PSI. Inches of water. Inches of mercury.

In a FADEC what is the result of Channel A failing to receive information from a sensor?. Channel B will assume control. Channel A will take the information from channel B. Channel A will take the information from the backup sensor.

A synchro pressure measuring system requires. alternating current. direct current. either ac or dc.

A synchro pressure measuring system works on the principle of changes in pressure related to changes in. frequency. voltage. flux.

Pure jet engines use. stagnation thermocouples. rapid response. variable resistance thermocouples.

Modern oil pressure servo transmitters sense. differential pressure. absolute pressure. HP oil pressure.

EGT thermocouples are usually made of. nickel and platinum. chromel and platinum. chromel and alumel.

Thrust is generated in a turboprop system by. moving a small mass of air quickly. moving a large mass of air quickly. moving a large mass of air slowly.

Power is adjusted in a variable pitch turboprop aircraft by. increasing RPM. increasing fuel flow. increasing pitch.

Thrust in a high bypass engine is measured by measuring. N3 RPM. fuel flow. neither of the above, thrust is not indicated in flight.

EPR is a ratio of. P1 to P4. P1 to Pfan. P1 to P6.

The majority of power in a free turbine engine is used to. drive the gas generator. drive the free turbine. expel gases through the exhaust.

The total power in a turboprop engine is the. SHP. ESHP. BHP.

To measure oil temperature, which of the following would most likely be used?. Resistance temperature measurement. Thermocouple measurement. Optical pyrometer.

Strain gauges may be used to measure. thrust. torque. pressure.

Piezo electric transducers convert. a tensile stress into a current output. a pressure input into a resistance output. a force input into a voltage output.

A broadband vibration reading indicates. the N1 vibration. the average vibration. the peak allowable vibration.

Vibration analysers determine which component is vibrating by analysing. frequency. amplitude. voltage.

An annular combustion chamber consists of. an air tube and a flame tube. an outer skin and an inner and outer flame skin. a series of flame tube in an air annulus.

What percentage of air passing through the combustion section is burned?. 40%. 50%. 75%.

A full flow oil system has. a single fixed minimum oil pressure. a hot and cold oil pressure limit. a variable oil pressure dependant upon throttle setting.

Oil quantity is transmitted to the EICAS by. a float switch in the oil tank. a reed switch ladder activated by magnetic float in the oil tank. a belt type capacitor system.

Thrust in a high bypass fan engine is indicated by. N1 RPM or EPR. N3 RPM or P1/P4 ratio. N1 RPM or N3 RPM.

The purpose of the LP fuel pump is to. ensure the fuel flow governor gets enough fuel. pump fuel from the aircraft fuel tanks to the engine. ensure the HP fuel pump does not cavitate.

The principle of operation of a DC ratio meter is. one coil moving in a uniform magnetic field. two coils moving in a uniform magnetic field. two coils moving in a non-uniform magnetic field.

A thermocouple indicator is basically a. millivoltmeter. milliohmeter. milliameter.

If a FADEC loses its ADC input, in the short term it will. go into soft redundancy. go into hard redundancy. go to limit protection mode.

With an aircraft with a fixed pitch propeller, what indication has the pilot got of the output power?. fuel flow. oil pressure. engine speed indicator.

The primary purpose of an EEC is. to change analogue inputs into digital format to provide glass cockpit information and reduce flight crew workload. to change analogue inputs into digital format to reduce flight crew workload and provide maintenance information. to save fuel, reduce crew workload and reduce maintenance costs.

If a tachogenerator indicated in reverse, the probable cause is. wrong input frequency. two phases cross connected. supply and transmitter cross connected.

A sensing element goes open circuit in a ratiometer. What will be happen?. Temperature indicates below ambient. Full scale deflection. Hairspring takes indicator off scale.

A thermocouple is constructed of. two dissimilar metals welded together. two dissimilar metals with an air gap between them. three dissimilar metals welded together.

A thermocouple indication is taken from the. hot junction. cold junction. difference between the hot junction and the cold junction.

On a twin spool engine, the HP compressor is driven by. ram air over the compressor. early stages of the turbine. later stages of the turbine.

In a multiple probe thermocouple system, what is the effect if one probe fails?. Increase in temp reading. Reduction in temp reading. No noticeable effect.

In a gas turbine if air is tapped from the H.P bleed. EPR decreases and EGT increases. EPR stays constant and EGT decreases. EPR increases and EGT decreases.

The vane on a vane type fuel flow measuring device becomes stuck. What safety backup is available for the engine fuel flow?. A fuel bleed valve. A bypass valve. A differential pressure bypass valve.

In a FADEC engine with a hydromechanical fuel system, how is fuel flow controlled?. By fuel pressure. By electro-hydraulic servo valves (EHSVs). By oil hydraulics.

In the HEIU the discharge resistor. allows sufficient voltage to be stored to provide relight facilities. protects the unit from excessive voltages. allows the capacitors to discharge when the unit is switched off.

A modular constructed gas turbine engine means that. its major assemblies can be removed and replaced. all engines have a specific component layout. the engine is constructed by the vertical assembly technique.

The purpose of a high pypass ducted fan engine is to. improve efficiency. improve thrust. reduce size.

When using a test set to test an EGT thermocouple circuit. no compensation for ambient temperature is required. only consider ambient temperature compensation if the ambient temperature is over 20oC. always compensate for ambient temperature.

Where is EGT measured?. In the combustion chamber. Downstream of the combustion chamber. Upstream of the combustion chamber.

How does a boost gauge compensate for altitude changes?. Spring sealed bellows. Two bellows against atmospheric pressure. There is no compensation.

An EMF is produced by a thermocouple. This is sensed. at the hot junction. at the cold junction. between the hot and cold junctions.

Supervisory EEC sends its output to the. fuel valve. HMU/FFG. EGT thermocouple circuit.

Ratiometer pointer movement is achieved by. one coil providing a torque against a permanent magnet. two opposing coils providing a torque in a varying magnetic field. two opposing coils providing a torque in a permanent magnetic field.

A fuel flow transmitter requires a motor or a synchronous motor to have a. constant voltage within small tolerances. constant frequency within small tolerances. low EMF as it is immersed in fuel.

A boost gauge measures. absolute pressure on the inlet port. brake mean effective pressure. gauge pressure at the injector.

On a thermocouple circuit on a non FADEC engine, what is the purpose of the ballast resistor?. To compensate for ambient temperatures. To standardise both engine`s EGT readings. To compensate for altitude.

Boost pressure is measured in. inches of Hg. inches of water. PSI.

Power is adjusted in a gas turbine engine by. increasing airflow to the combustion chamber. increasing air and fuel flow. increasing fuel flow.

The EPR reading is taken from a ratio of. jet pipe pressure to compressor inlet pressure. compressor delivery pressure to compressor inlet pressure. turbine inlet pressure to compressor delivery pressure.

The basic gas turbine engine cycle is. induction, compression, combustion, expansion, exhaust. induction, compression, expansion, combustion, exhaust. compression, combustion, induction, expansion, exhaust.

The high bypass duct. drives a cabin air compressor. provides engine cooling. improves propulsive efficiency.

If an engines fadec system loses air data permanently the pilot will. select alternate pitot static. switch to alt on the relevent EEC. turn that EEC off.

An EPR system reads slightly over 1, this would mean. the transmitter datum point has moved and needs replacing. no action required this is normal. the indicator needs re-calibrating back to 1.

Manifold pressure is measured. at inlet port above and below ambient conditions. at inlet port above and below standard atmosphere at sea level. at inlet port indicating boost pressure.

A temperature indicating system incorporating a resistance bulb on a selected range has pointer movement. proportional to bulb resistance. inversely proportional to bulb resistance. resistance does not affect pointer movement.

In a ducted fan engine, the fan is driven by the. accessory gearbox. turbine. air passing over the compressor.

In a FADEC system, active control switchover occurs. on engine startup only. when channels A and B are healthy. on shutdown.

Gas turbines work on the. otto cycle. brayton cycle. diesel cycle.

Oil systems consists of. 2 systems. 3 systems. 4 systems.

With the EEC in control the throttle levers are always. in the fully forward position. in the fully aft position. anywhere between the fully fwd and fully aft positions.

Turboprop thermocouple probes are. rapid response. stagnation. surface mounted.

Propelling nozzle provide. pressure thrust. velocity thrust. pressure and velocity thrust.

How are the combustion chambers cooled?. By l.p compressor air. By h.p compressor air. By fan pressure air.

Fan blade speed is measured by. phonic wheel. drag cup and tachometer. eddy currents.

Fadecs operate by. 2 controlling 1 operating. 1 controlling 1 operating. 2 units each capable of independent control.

When a thermocouple fails, the temperature reading will. over read. under read. stay the same.

An aircraft flying at 800mph would typically use. turbojet. turbofan. turboprop.

The inlet of a turbo fan is. divergent. convergent. convergent-divergent.

What is the pressure increase over one stage of a centrifugal compressor?. 5:1. 1.2:1. 8:1.

The bleed valve on a engine at start up is. open. closed. modulating.

EPR is measured between inlet and. jet pipe. cold and hot exhaust. front of turbine.

One stage of a turbine is. n.g.v then turbine blade. turbine blade then n.g.v. i.g.v then turbine blade.

in a flow type fuel system, fuel shutoff is done by. mechanical ball valve. fcu torque motor. l.p fuel cock.

The fuel flow transmitter is downstream of. prsov. h.p pump. l.p pump.

How is fuel flow varied in a variable displacement pressure type pump?. Alter the camplate angle. Remote servo pressure. Direct cable to camplate.

When the full authority fuel control unit is changed, the rating plug. stays with the engine. stays with the FAFC. is replaced every time.

The EEC is powered and able to operate via. only a dedicated alternator. the aircraft electrical system. The EEC is capable of being powered by both independently depending on conditions.

The EEC uses. ARINC 429 formatted data. ARINC 629 formatted data. uses neither ARINC 429 or 629 formatted data.

The fuel metering unit has direct inputs via. only the EEC. the EEC and the fire control handle. the EEC, fire control handle and the engine master switch.

The optimum turbine speed is defined as. the most efficient speed of the turbine. 100% rpm of the engine. 95 % rpm of the engine.

An increase in fuel flow through the impeller type fuel flow transmitter is measured by. drum lags impeller. impeller lags turbine. decreasing angle between the two.

No power to EGT is indicated by. yellow flag in front counter. bug moves in the x direction. bug moves in the y direction.

Connection to a tachogenerator. 3 phase star. 3 phase delta. 2 phase star.

A short circuit in a d.c ratiometer will give. max scale reading. zero scale reading. min scale reading.

An open circuit in a d.c ratiometer will give. max scale reading. zero scale reading. min scale reading.

A compressor shaft rotates on. sintered bearings. ball and roller bearings. plain bearings.

The EEC changes power settings by. changing the throttle lever angle. changing the fuel flow input. changing the airflow input.

A torque pressure measuring indicator is fed by. direct oil pressure. differential pneumatic pressure. servo operated.

The tacho generator output has: A fixed frequency. A Variable frequency. A DC Current output.

On a fuel flow measuring device located on the engine. no adjustments can be made. external adjustments can be made for maximum rate fuel flow. external adjustments can be made for minimum rate fuel flow.

Where is the hot junction of a EGT thermocouple system found?. In the indicator. Upstream of the combustion chamber. Downstream of the combustion chamber.

The fan on a turbofan engine is turned by. induction of the air across the fan into the compressor. the turbine section. the combustion chamber gases.

When terminating connections for a EGT sensing system. ensure that the pins and sockets are correctly crimped and brazed. ensure that all connections are silver soldered. ensure that the pins and sockets are of the same material as the leads.

An EPR gauge indicates `1`. You should. adjust the indicator back to zero. replace the indicator, there is no adjustment. do nothing this is what it should read with the engine shut down.

A Gas Turbine`s propulsion force is produced by. reaction of the rearward moving gasses. impingement of the gasses on the surrounding air. induced airflow into the engine.

In a single spool gas turbine engine the compressor rev/min is. more than the turbine speed. less than the turbine speed. equal to the turbine speed.

A tacho pointer is moved by. drag cup coupling. ac servo motor. synchronous motor.

In a twin spool engine. the HP turbine drives both LP and HP compressors. the LP turbine drives the LP compressor and the HP turbine drives the HP compressor. the HP turbine drives the LP compressor and the LP turbine drives the HP compressor.

Relative permeability of fuel is also known as. density of the fuel. weight of the fuel. dielectric constant of the fuel.

The cycle of a gas turbine engine is. completed in one revolution of engine. completed in two revolution of the engine. continuous.

Engines having two independent moving systems are. compound engines. twin spool engines. complex engines.

Compression ratio of compressor of gas turbine Engine is. outlet pressure to Inlet pressure. measured across all rotor stages of compressor. mass of airflow to combustion.

Torque pressure indication to measure power output of an engine is. used in all Gas Turbine engines. not used in Gas Turbine engines. only used when engine output pressure is used for torque not for thrust.

Manifold pressure is measured in. direct absolute pressure in Bars. differential pressure in millibars. direct absolute pressure in inch of Hg.

Typically a torque pressure indication system is. differential pressure type. remote synchronous type. direct Oil Pressure sensing type.

A tachometer used to measure Rev/Min in turbine engines. develops its own power for the system. 28V dc is required. 115V ac is required.

Primary power for electronic engine control. 115V ac essential bus. on side 115V ac bus bar supply. Permanent Magnet Alternator.

Leads to measure thermocouple temperature are. calibrated for circuit in used and cannot be shortened. affected by Magnetic and electrical interference. insulated by heat legging device to reduce errors in the indication end.

A thermocouple sensing system test set requires. a serviceable battery. No power. 24V dc.

The HP compressor is powered by. the first set of turbines. the last set of turbines. the intermediate compressor.

Torque is measured in gas turbine engines. never. where there is a free turbine providing the power. on small pure jet engines.

What is the supply voltage to tacho generators?. 28vdc. 115vac. It has no supply.

A FADEC takes measurements of engine speed,. temperature and pressure. temperature. pressure.

The fuel metering valve in the hydro mechanical unit of a FADEC system is operated by. hydraulic servo pressure. fuel servo pressure. electrical servo.

Boost pressure is. atmospheric above ambient. atmospheric below ambient. the absolute of the manifold chamber.

To check/test a temperature indicator you would. connect a decade box in place of the temperature sensing element. connect a decade box in series with the temperature sensing element. connect a decade box in parallel with the temperature sensing element.

Calibration for a ratiometer type temperature indicator takes into account. the material of the coils. the material of the sensing element. the type of representation on the dial.

Reverse thrust can only be selected when the throttle is. 75% power position. open. at the idle stop.

On a FADEC engine the EEC. has electronic control of the hydro-mechanical fuel control unit in all modes. has electronic control of the hydro-mechanical fuel control in some modes. has mechanical control of the hydro-mechanical fuel control system.

EPR is a measure of. exhaust pressure compared to compressor inlet pressure. exhaust pressure compared to combustor pressure. combustion pressure compared to compressor inlet pressure.

What exactly does a thermocouple measure?. The difference between the hot and cold junction. Hot junction temperature. Cold junction temperature.

In a temperature sensing ratiometer what determines the actual temperature?. The material of the sensor. The material of the sensing coil. The material of the balancing coil.

Torque is a useful measure. on engines where a portion of thrust produces torque. on engines which only produce thrust. on all engines.

Boost pressure is a measure of. manifold pressure. atmospheric pressure plus turbocharger inlet pressure. atmospheric pressure less turbocharger inlet pressure.

The test switch of a continuous loop fire detector gives a. continuity check. bonding check. insulation check.

What are the types of continuous fire detection system?. Capacitive and resistive. Capacitive. Inductive and capacitive.

During normal running conditions. combustion is continuously supported by ignition. combustion is intermittently supported by ignition. combustion is self supporting.

What indication does the pilot receive that thrust reversers have deployed?. A feeling of rapid deceleration. An audible warning. A sequence of lights.

on a fixed pitch propeller single engine aircraft, what is indicated as a measure of power?. Oil pressure. Engine speed. Cylinder head temperature.

in a turbine engine used to drive a propeller, the power from the engine is. majority for jet reaction and the residual to drive the prop. the majority of power is used to drive the prop, with the residual giving a jet reaction. the power is divided equally.

The term "Mass Flow" as used in a jet engine refers to. total mass of air divided by time. total volume multiplied by velocity of airflow. total volume of air multiplied by relative density.

The HMU of a FADEC engine increases fuel flow by increasing. air flow through the compressor. hydraulic servo pressure. servo fuel pressure.

The EEC controls thrust by. Moving the throttles. Increasing fuel flow. Controlling the bleed valves.

When an EGT harness goes through a bulkhead disconnect you must ensure that. pins and sockets are of the same material as the thermocouple leads. the pins etc should be silver soldered and their connections properly made. pins and sockets must be correctly crimped or braised and tested using a 250 Volt megger.

The physical law used for calibrating a thermocouple indicator depends on. the materials of the sensing element. the materials of the coils in the meter. the range that the meter is required to read - i.e. operating scale.

On a gas turbine engine, what is the fan driven by?. HP turbine. LP turbine. IP turbine.

The starter light is on during a start cycle (low voltage electrical starter). This is normal for 30 seconds, take no action. If the light stays on after 30 seconds action is required. Indicates electrical power is flowing to the starter.

A DC starter motor disconnects due to. current increasing switching off an overspeed relay. current decreasing switching off an overspeed relay. a centrifugal switch that acts like an overspeed relay.

Gas type fire wires operate by utilizing. the change in the gas pressure. the change in the gas dilectric level. the change in the electrical resistance of the gas.

Integrated fuel flow gives. fuel flow and acceleration. average fuel flow. total fuel consumed.