Modulo 11

What is the main reason for using a stabilator or a horizontal stabilizer with variable incidence?. To increase the aircraft's maximum speed. To minimize drag when trimming the aircraft in flight. To increase the weight of the aircraft.

What is one advantage of varying the angle of the horizontal stabilizer?. It reduces drag and can allow a smaller elevator. It increases the fuel consumption. It eliminates the need for a vertical stabilizer.

How does a canard differ from an aft-tail design?. A canard produces lift and helps hold the nose up. A canard always produces downward force. A canard is only used to control yaw.

What is the function of a servo tab?. To increase the weight of the control surface. To aerodynamically position a control surface that requires too much manual force. To prevent the aircraft from stalling.

What is the function of a spring tab?. It helps move control surfaces when aerodynamic forces are high. It increases lift during slow flight. It controls the aircraft's engine speed.

When is a spring tab inactive?. During high-speed flight. During slow flight. During takeoff only.

How can the correct amount of bend in a control surface be determined after an adjustment?. Only by inspecting it from the ground. By using the aircraft's weight and balance data. Only by flying the aircraft after the adjustment.

Where should the center of lift of a control surface be located to prevent flutter?. Forward of the control surface center of gravity. Aft of the control surface center of gravity. Exactly at the control surface center of gravity.

What is the purpose of a wing fence or stall fence?. To increase the fuel capacity of the wing. To stop spanwise airflow along the wing. To increase the aircraft's weight.

What is Zone 700 used for?. Landing gear and landing gear doors. Flight deck and avionics. Fuel tanks and fuel lines.

How are most components attached to the aircraft structure?. They are mounted to or attached to the structure using bonding straps. They are only welded to the structure. They are attached only with adhesive tape.

What causes interference in radio communications due to precipitation static?. Corona discharge emitted from the aircraft. Excessive fuel flow. Hydraulic pressure.

What produces noise in the radio frequency spectrum during corona discharge?. Short pulses of corona discharge. Continuous electrical current. Mechanical vibration of the wings.

Where are static dischargers normally installed?. On the trailing edges of control surfaces, wing tips, and the vertical stabilizer. On the leading edges of the wings only. Inside the landing gear bays.

What are safe-life structural elements?. Elements with a very low risk of unacceptable degradation or failure for a specified period of time. Elements designed to operate without any inspection. Elements that can never fail under any circumstances.

What is bending stress?. A combination of compression and tension. A combination of torsion and shear only. Pure compression.

What does an external drain do?. Dumps fluid overboard. Pumps fluid back into the hydraulic system. Stores excess fluid inside the aircraft.

In an unpressurized aircraft, how may external drains operate?. They may remain open at all times. They must always remain closed. They may only be opened during takeoff.

What is the function of stringers and longerons in the fuselage?. They prevent tension and compression from bending the fuselage. They control the aircraft's yaw. They increase the hydraulic pressure.

When are close-tolerance bolts used?. When a tight drive fit is required. When a loose fit is required. Only when attaching electrical wires.

What is an alternative to anodizing for surface protection of magnesium and zinc alloy parts?. Chromate. Nickel. Steel.

How do most engine pylons attach to the fuselage?. At two points, extending out away from the fuselage. At one point only, directly to the landing gear. At three points, only to the vertical stabilizer.

Where is the landing gear typically attached on low-wing aircraft?. To the wing spars, retracting into the wheel wells in the fuselage undercarriage. To the horizontal stabilizer. To the engine pylons only.

Why do wide-body aircraft have additional tracks?. To accommodate three sections of seats across the width of the fuselage. To support additional engines. To accommodate larger landing gear.

What is an advantage of a heated aircraft window?. It is more resistant to impact breakage. It is lighter than an unheated window. It does not require any structural support.

What type of windows are normally used for passenger cabin windows?. Fixed plug-type windows. Sliding windows. Removable hinged windows.

How are passenger cabin windows generally constructed?. With two panes and a seal between them. With one thick pane and no seal. With three panes and no seal.

Under normal flight conditions, which parts of a passenger window take the differential pressure loads?. Both panes. Only the outer pane. Only the inner pane.

What is airborne towing?. A method used to launch gliders into the air using a powered aircraft. A method used to tow aircraft on the ground. A method used to move baggage between aircraft.

How do cabin entry doors and baggage compartment doors contribute to the fuselage?. When closed, they help strengthen the fuselage. They reduce the weight of the fuselage. They provide additional fuel storage.

What are the spars?. The principal structural members of a wing. The secondary control surfaces of a wing. The protective covers of the engines.

What loads do the wing spars support?. Distributed loads and concentrated weights such as the fuselage, landing gear, and engines. Only aerodynamic loads. Only the weight of the fuel.

How can a wing spar be constructed?. It can be extruded from one piece of metal or built up from multiple extrusions or formed angles. It can only be made from a single piece of wood. It is always made from a single sheet of aluminum.

Which structural member takes the main wing bending and shear loads?. The main spar. The wing skin only. The wingtip.

Why is a wing spar tapered from root to tip?. Because the bending moment is greater at the root. Because the wingtip carries more weight. Because the root has less aerodynamic load.

What is the empennage?. The horizontal and vertical stabilizers located at the aft end of the fuselage. The landing gear assembly. The engine nacelle and pylon assembly.

What structural elements are used in the empennage similar to those found in a wing?. Spars, ribs, stringers, and skin. Bolts, wheels, and tires. Engines, pylons, and nacelles.

What are the four main structural items of a horizontal stabilizer?. Spar, rib, stringers, and skin panels. Pylon, nacelle, rib, and landing gear. Skin, engine, spar, and wheel well.

How is mass balancing of a flight control accomplished?. By adding mass balance weights to the leading edge of the control. By adding weights to the trailing edge. By removing all weights from the control surface.

What is the purpose of moving the center of gravity of a flight control forward?. To make the part behind the hinge line as light as possible and help eliminate flutter. To increase the weight behind the hinge line. To increase aerodynamic drag.

Where are mass balance weights attached when mass balancing control surfaces?. Forward of the hinge line. Aft of the hinge line. Directly on the control surface trailing edge.

What materials are commonly used for the exterior skin of a nacelle?. Sheet aluminum or magnesium alloy, with stainless steel or titanium used in high-temperature areas. Only carbon fiber. Only stainless steel throughout the entire nacelle.

Where are stainless steel or titanium alloys commonly used on a nacelle?. In high-temperature areas, such as around the exhaust exit. Inside the passenger cabin. Around the landing gear wheels.

What are engine mounts usually made from on light aircraft?. Chrome/molybdenum steel tubing. Aluminum sheet only. Titanium sheet only.

What are engine mounts usually made from on larger aircraft?. Forged chrome/nickel/molybdenum assemblies. Wooden structures. Plastic tubing.

What determines the pressure level in the cabin?. The position of the valve. The aircraft's speed only. The engine oil temperature.

What types of control are often combined in modern aircraft pressurization systems?. Hydraulic, mechanical, and fuel control. Only mechanical control. Pneumatic, electric, and electronic control.

What does the controller's electric output signal drive in many small transport and business jets?. The landing gear actuator. A torque motor in the primary outflow valve. The fuel pump.

How many cabin pressure controllers are commonly used on many transport category aircraft?. Two cabin pressure controllers, or one controller with redundant circuitry. Only one controller with no backup. Three controllers operating independently.

What is the function of a cabin air safety valve?. It controls the temperature of the cabin. It supplies fresh air to the cockpit. It is a pressure relief valve that opens at a predetermined pressure differential.

It is a pressure relief valve that opens at a predetermined pressure differential. Between 2 and 4 psid. Between 8 and 10 psid. Between 15 and 20 psid.

What is the purpose of a cabin altitude limiter?. To increase the cabin altitude during descent. To increase the differential pressure above the maximum limit. To close the outflow valves when cabin pressure drops well below the normal range, preventing a further increase in cabin altitude.

Where can some cabin altitude limiter functions be incorporated?. Into the outflow valve. Into the landing gear. Into the engine fuel pump.

What does the constant differential mode of pressurization control maintain?. A constant cabin temperature. A constant pressure difference between the cabin air and ambient air. A constant cabin altitude regardless of pressure.

Why is the pressure differential in constant differential mode kept below the maximum structural differential?. To maintain the integrity of the pressure vessel. To increase engine thrust. To reduce cabin temperature.

To reduce cabin temperature. Because the cabin temperature becomes too high. Because the engines stop producing bleed air. Because maintaining the selected cabin altitude could result in a differential pressure above the airframe design limit.

What device may be used on smaller turbine aircraft or sections of large aircraft to multiply jet pump flow?. A hydraulic accumulator. A jet pump flow multiplier. A jet pump flow multiplier.

Where is bleed air taken from when using a jet pump flow multiplier?. From the fuel tank. From the compressor section of the turbine engine. From the exhaust nozzle.

Where is the warm air supply provided from in a bleed-air air-conditioning system?. From the gas turbine engine compressor. From the aircraft's fuel tank. From the cabin exhaust.

What is the purpose of the aircraft APU in relation to bleed air?. To provide hydraulic pressure for the landing gear. To cool the aircraft engines during flight. To provide pressurized bleed air for engine starting and operation of the air-conditioning packages.

What happens to the bleed air after passing through the secondary heat exchanger?. It flows directly into the fuel tank. It flows back into the air cycle machine, where it drives an expansion turbine and cools further. It is heated again by the engine exhaust.

What is the dividing point between the low side and high side of a vapor cycle system?. The evaporator. The compressor. The condenser.

What type of sensors are used as cabin temperature pickup units and duct temperature sensors?. Pressure switches. Thermocouples only. Thermistors.

When do vacuum relief valves operate?. When cabin altitude exceeds aircraft altitude. When aircraft altitude exceeds cabin altitude. When cabin temperature exceeds the selected temperature.

How is the indicated section of a pneumatic system typically shut off?. By opening the outflow valve. By increasing the bleed-air pressure. By closing an isolation valve or shutoff valve.

What are the three basic kinds of aircraft instruments classified by the job they perform?. Engine instruments, electrical instruments, and hydraulic instruments. Flight instruments, engine instruments, and navigation instruments. Flight instruments, fuel instruments, and communication instruments.

What type of instruments monitor systems such as flight controls, cabin environmental systems, electrical power, and APUs?. Navigation instruments. Engine instruments. Position/condition instruments.

What does an altimeter display?. Aircraft speed. Aircraft altitude. Aircraft heading.

What happens to the aneroid when air pressure is reduced as the aircraft climbs?. It contracts and decreases the indicated altitude. It remains unchanged. It expands and displays a higher altitude.

What does the third, shortest or thinnest pointer on an altimeter indicate, if fitted?. Altitude in 1,000-foot increments. Altitude in 10,000-foot increments. Altitude in 100-foot increments.

Altitude in 100-foot increments. On the magnetic compass. On the engine display. On the electronic primary flight display near the artificial horizon.

What type of temperature compensation may be included in analog airspeed instruments?. Hydraulic compensation devices. Bimetallic temperature-compensating devices. Magnetic compensation devices.

What do bimetallic temperature-compensating devices alter in an analog airspeed instrument?. The aircraft's engine speed. The static pressure. The linkage movement between the diaphragm and the pointer.

What does a Machmeter indicate?. Aircraft altitude. Aircraft magnetic heading. Mach number.

At high altitudes, which type of gyro is more efficient?. Electric gyros. Pressure-driven gyros. Magnetic gyros.

What instruments can be combined to provide an accurate method of direction indication?. An altimeter, airspeed indicator, and ADF. A gyro, a magnetic compass, and a remote indicating system. A VOR, DME, and weather radar.

What is a thermocouple?. A pressure sensor. A type of magnetic compass. A circuit or connection of two unlike metals.

In which units can a thermocouple system be calibrated?. Knots or Mach. Fahrenheit or Celsius degrees. Feet or nautical miles.

What are the two basic types of modern autopilot systems?. Position-based and rate-based. Hydraulic-based and pneumatic-based. Magnetic-based and electrical-based.

How do rate-based autopilots operate?. They only maintain the aircraft's altitude. They control the aircraft based only on its position. They use information about the rate of aircraft movement and move control surfaces to counter the rate of change causing the error.

What type of autopilot system is commonly used on most large aircraft?. Position-based autopilot. Rate-based autopilot. Manual autopilot.

What are the four basic components of most autopilot systems?. Gyros, compasses, antennas, and displays. Sensing elements, computing elements, output elements, and command elements. Sensors, engines, hydraulic pumps, and actuators.

What is SELCAL?. A type of weather radar. A selective calling feature used with VHF or HF radio. A satellite navigation system.

What radio systems does SELCAL work in conjunction with?. Only VHF. Only HF. VHF or HF radio.

What is INMARSAT?. A type of aircraft weather radar. A type of autopilot. A commercially available satellite communication system.

How many orbiting satellites are mentioned in the text as being used by the INMARSAT system?. Five satellites. Twenty satellites. Ten satellites.

What happens when the BFO is selected on an ADF receiver/controller?. The VOR receiver is activated. An internal beat frequency oscillator is connected to the IF amplifier inside the ADF receiver. The weather radar antenna is activated.

How are the two loop antennas arranged on most modern ADF systems?. Parallel to each other. At 45° to each other. At 90° to each other.

What does the Radio Magnetic Indicator (RMI) combine?. Indications from a magnetic compass, VOR, and ADF. Indications from the DME, weather radar, and GPS. Indications from the altimeter, VSI, and airspeed indicator.

What does a traditional DME display?. Aircraft altitude. Aircraft magnetic heading. The distance from the DME transmitter antenna to the aircraft.

What is the distance displayed by a traditional DME called?. Ground distance. Horizontal distance. Slant distance.

What equipment does VOR-based RNAV use?. The ADF receiver, loop antenna, and RMI. The VOR receiver, antenna, and VOR display equipment such as the CDI. The DME receiver, radar antenna, and weather display.

What type of radio waves does primary radar transmit?. VHF and HF radio waves. Directional UHF or SHF radio waves. Only LF radio waves.

How does primary radar transmit its directional radio waves?. Only vertically. Only toward the rear of the aircraft. Sequentially in all directions.

How are heavy weather radar returns normally displayed?. Heavy returns are green. Heavy returns are yellow. Heavy returns are red.

How are medium weather radar returns normally displayed?. Medium returns are red. Medium returns are yellow. Medium returns are blue.

How are light weather radar returns normally displayed?. Light returns are green. Light returns are red. Light returns are yellow.

In which direction are weather radar signals transmitted?. Rearward from the aircraft. Vertically upward. Forward of the aircraft.

Where is the weather radar directional antenna usually located?. Inside the cockpit. On top of the vertical stabilizer. Behind a nonmetallic nose cone.

What happens when an alert condition occurs on a weather radar system equipped with this function?. The radar is automatically switched off. An alert is annunciated. The aircraft automatically descends.

What type of turbulence cannot be detected by weather radar?. Dry air turbulence. Thunderstorm turbulence. Heavy precipitation turbulence.

What must be attenuated when the weather radar includes terrain features?. Aircraft altitude. Radio communication. Ground clutter.

Which radio frequency system is normally used for communication over distances greater than 300 miles?. VHF. UHF. HF.

What is the phase difference between the sine waves in a three-phase electrical system?. 90°. 120°. 180.

How are some alternators cooled?. By circulating fuel through the alternator. By circulating hydraulic fluid through the alternator. By circulating oil through the internal components of the alternator.

What is the purpose of a Constant-Speed Drive (CSD)?. To control the aircraft's electrical voltage. To ensure the alternator rotates at the correct speed to produce a 400 Hz frequency. To increase the engine's fuel flow.

What happens when an Integrated Drive Generator (IDG) is disconnected in flight?. It automatically reconnects when the aircraft descends. It can be reconnected in flight by the pilot. The disconnection is irreversible and the system can only be reconnected on the ground with the engine shut down.

How many coils of wire does the armature of a DC alternator contain?. One coil. Two coils. Three coils.

How is the Boeing 747-400 split parallel electrical system controlled?. By four GCU and two BPCU. By two GCU and four BPCU. By one GCU and one BPCU.

What type of inverters do most modern aircraft use?. Rotary inverters. Mechanical inverters. Solid-state static inverters.

How are the primary windings of current transformers connected?. In parallel with the primary circuit. In series with the primary circuit. Connected directly to ground.

How is the coefficient of coupling calculated if 10,000 lines of force are produced by the primary and 9,000 cut across the secondary?. 0.5. 0.9. 1.9.

If a transformer has a step-up ratio of 4:1 and the primary voltage is 10 volts, what is the secondary voltage?. 10 volts. 20 volts. 40 volts.

If a transformer has a step-up ratio of 4:1 and the secondary voltage is 40 volts, what is the secondary current when the primary current is 4 amps?. 4 amps. 1 amp. 16 amps.

What happens if a ground power source with reverse polarity is connected to the aircraft?. The external power solenoid closes immediately. The diode increases the current flow. The diode blocks the current and the external power solenoid does not close.

What do Transformer Rectifier Units (TRUs) convert?. 28 V DC into 115 V AC. 115 V AC into 28 V DC. 400 Hz AC into 115 V AC.

What happens when the aircraft is on the ground with external power connected?. The aircraft uses only battery power. The engine alternators provide all the DC power. A separate TRU converts the AC from the ground source to 28 V DC to power the distribution buses.

What do CS-25 specifications apply to?. Large commercial aircraft. Small general aviation aircraft. Military helicopters.

What does an airliner comply with when it is certified according to CS-25?. Only engine performance requirements. Requirements for the installation of emergency equipment according to CS-25 specifications. Only passenger comfort requirements.

What emergency equipment requirements are covered by CS-25?. Only the number of fire extinguishers. Only emergency lighting. The number, type, and location of emergency doors, seat belt strength, emergency lighting parameters, and life raft locations.

How many fire extinguishers must there be in a cabin with 61 to 200 passengers?. Two extinguishers. At least three extinguishers. At least five extinguishers.

How is the CO₂ in a life vest released?. Automatically when the aircraft lands. By pulling an electrical switch. Manually.

What gas are aircraft emergency escape slides usually pressurized with?. Oxygen. Nitrogen. CO₂.

How do overhead storage bins extend through the cabin?. They are located only above the cockpit. They are installed only in the rear of the cabin. They run the length of the cabin.

Where are galleys typically installed?. Only in the cockpit. Into the same floor tracks as the passenger seats, although dedicated fittings may also be used. Only inside the cargo compartment.

What are cargo containers commonly known as?. Cargo Storage Units (CSUs). Aircraft Cargo Boxes (ACBs). Unit Load Devices (ULDs).

How are variable resistance networks monitored?. By applying 28V DC to the detector wire from the detector control unit. By applying 115V AC to the detector wire. By applying 28V AC to the detector wire.

What is used to extinguish Class A fires?. CO₂. Water. Halogen gas.

What powers the lavatory smoke detector?. 115V AC from the essential AC bus. 28V DC from the battery bus only. 28V DC from the left/right main DC bus.

When the control is moved to the left, what happens to the ailerons?. The left aileron rises above the wing and the right aileron descends below the wing. The left aileron descends and the right aileron rises. Both ailerons rise above the wing.

In which direction do balance tabs move compared with the primary flight control?. In the same direction. They remain stationary. In the opposite direction.

When are flight control locks used?. During normal cruise flight. During gusty weather conditions. Only during takeoff.

When does a common landing gear warning occur?. When all landing gear members are locked in the down position. When the aircraft reaches maximum speed. When all landing gear members are not locked in the down position and a throttle lever is reduced to a low power setting.

How are balance panels typically constructed?. From aluminum skin-covered frame assemblies or aluminum honeycomb structures. From steel plates only. From carbon fiber and titanium only.

What happens when a control surface moves from the neutral position?. The differential pressure across the balance panel decreases. Differential pressure builds up across the balance panel. The pressure across the balance panel becomes zero.

What effect does the differential pressure have on the balance panel?. It opposes the movement of the control surface. It has no effect on the control surface. It acts in a direction that assists the control surface movement.

How do fly-by-wire control systems transmit the pilot's actions?. Through hydraulic cables directly to the control surfaces. Through electrical signals from the flight deck, through a computer, to the flight control actuators. Through mechanical cables directly to the actuators.

What would happen without the flight control computers reacting to aircraft instability?. The aircraft would become easier to control. The aircraft would automatically stabilize itself. The pilot would experience great difficulties controlling the aircraft.

What happens to fly-by-wire spoiler panels if electrical power is removed?. They move fully upward. They remain in their current position. They move down if they are not already down.

What happens to the ailerons and spoilers when the fly-by-wire load alleviation function operates in turbulent weather?. They move asymmetrically downward. They remain in the neutral position. They move symmetrically upward.

What is an advantage of fly-by-optics systems compared with fly-by-wire systems?. They require more electrical wiring. They are heavier. They are more immune to electrical interference.

What are the three most common methods used to balance control surfaces?. The pressure method, weight method, and torque method. The calculation method, scale method, and balance beam method. The hydraulic method, electrical method, and mechanical method.

What does the scale method of balancing a control surface require?. A pressure gauge graduated in pounds. A torque wrench calibrated in degrees. A scale graduated in hundredths of a pound or a similar unit.

What materials are most commonly used to balance control surfaces?. Aluminum and magnesium. Lead or steel. Titanium and copper.

What must happen to spilled fuel?. Spilled fuel must not enter the fuel tank compartment or any part of the airplane other than the tank itself. Spilled fuel must be directed into the engine compartment. Spilled fuel may remain anywhere inside the fuselage.

Where must a fuel strainer or filter be installed?. After the fuel metering device. Between the fuel tank outlet and the inlet of either the fuel metering device or the nearest engine-driven positive displacement pump. Only inside the fuel tank.

How are bladder-type fuel tanks secured?. With welded joints. With standard bolts. With press-type rivets.

What is the function of cross-feed valves?. They control the fuel temperature. They prevent fuel from reaching the engines. They permit fuel transfer from any tank to any engine.

How should a fuel truck be positioned when servicing an aircraft?. Behind the fuselage and perpendicular to the wings. Parallel to the wings and in front of the fuselage, if possible. Underneath the aircraft fuselage.

What type of fuel quantity systems are typically used on large and high-performance aircraft?. Mechanical float systems only. Electronic fuel quantity systems. Hydraulic fuel quantity systems.

What type of warning switch is commonly used at the outlet of each fuel boost pump on turbine-powered aircraft?. A high-pressure warning switch. A temperature warning switch. A low-pressure warning switch.

Where may additional fuel filters be installed on turbine-engine aircraft?. Only inside the fuel tank. Between the engine-driven fuel pump and the fuel metering device. Only after the fuel metering device.

What is a fuel leak called when the affected area is less than 3/4 inch in diameter?. A seep. A stain. A spray.

What color do surfactants usually appear when present in large quantities?. Light blue to green. Tan to dark brown. Bright red to orange.

What is normally done with the micron filter element when it is removed?. It is cleaned and reused. It is normally thrown away. It is stored for later inspection.

At what differential pressure does the spring-loaded relief valve bypass fluid when the filter element becomes clogged?. 25 psi. 50 psi. 75 psi.

What material is the micron filter element made of?. Metal mesh. Fiberglass. Specially treated paper.

What size of solid particles is the micron element designed to prevent from passing through?. Greater than 5 microns. Greater than 10 microns. Greater than 25 microns.

How are packings and gaskets suitable for Skydrol fluid always identified?. With a red stripe. With a blue stripe. With a green stripe.

What color must always be present in O-ring color codes compatible with hydrocarbon fluid?. Blue. Red. Yellow.

What does a colored stripe around the circumference of an O-ring indicate?. The O-ring is for high-pressure oxygen systems. The O-ring is for electrical systems. The O-ring is a boss gasket seal.

What color stripe indicates that an O-ring is compatible with fuel?. Yellow. Blue. Red.

What color stripe indicates compatibility with hydraulic fluid?. Red. Blue. Green.

What determines the number of ports on a selector valve?. The size of the actuator. The particular requirements of the system. The pressure of the reservoir.

What type of selector valve is most common in aircraft hydraulic systems?. Three-port open-centered valves. Four-port closed-centered valves. Six-port open-centered valves.

What are four-port closed-centered selector valves commonly called?. Three-way valves. Five-way valves. Four-way valves.

When a selector valve sends pressure to one actuator port, what happens to the other actuator port?. It is blocked from all connections. It is connected to the pressure line. It is simultaneously connected to the reservoir return line.

Where are electrically driven hydraulic pumps commonly installed on large aircraft?. Inside the engine nacelles. In the wheel well or in a hydraulics bay near the wing root. Inside the fuel tanks.

What is the main purpose of electrically driven hydraulic pumps?. To replace all engine-driven pumps during normal flight. To transfer hydraulic fluid between systems. To provide hydraulic power during emergencies or ground operation when the engines are not running.

When does clear ice formation occur?. When droplets are very small, such as in fog. When droplets are large, such as in rain or cumuliform clouds. Only when the temperature is above freezing.

What are the main characteristics of clear ice?. Soft, light, and easy to remove. Hard, heavy, and tenacious. Brittle, light, and easy to remove.

Why is clear ice especially difficult to remove?. Because it is very light. Because it forms only on the ground. Because it is hard, heavy, and tenacious.

How does rime ice compare with clear ice?. Rime ice is harder and heavier. Rime ice is more difficult to remove. Rime ice is brittle and more easily removed than clear ice.

How are the de-icer boot air cells connected to the system?. By rigid metal pipes. By non-kinking flexible hoses to system pressure and vacuum lines. By electrical cables only.

How does the de-icer boot receive electrical current?. Through a hydraulic pump. Through the pneumatic system. Through a slip ring and brush assembly on the spinner bulkhead.

What does the WAI valve control?. The flow of hydraulic fluid to the landing gear. The flow of fuel to the engines. The flow of bleed air from the pneumatic system to the WAI ducts.

How long must the airplane have been on the ground for the WAI BITE periodic test to occur?. Less than 1 minute. Between 1 and 5 minutes. More than 10 minutes.

How often can the WAI BITE periodic test occur based on the time condition?. Every 12 hours. Every 18 hours. When more than 24 hours have passed since the last periodic test.

Why are the pilot’s and copilot’s windshield wipers sometimes operated by separate systems?. To reduce electrical power consumption. To increase the wiping speed. To ensure clear vision through one window if one system fails.

When should an operational check of the rain removal system be performed?. Only during scheduled heavy maintenance. Only after a flight. Whenever a system component is replaced or the system is suspected of not working properly.

Which systems can aircraft use for rain removal?. Only windshield wipers. Only chemical rain repellent. Windshield wipers, chemical rain repellent, pneumatic rain removal, or hydrophobic windshield coatings.

What color is commonly used for strobe anti-collision lights?. Red. White. Blue.

Where are strobe lights usually mounted?. On the landing gear. At the wing tips and possibly at the empennage extremities. Inside the passenger cabin.

What type of light do strobe lights produce?. A dim continuous red light. A steady white light. An extremely bright intermittent flash of white light.

Why are strobe lights highly visible?. Because they remain continuously illuminated. Because they use colored lenses. Because they produce extremely bright intermittent flashes.

How may each aircraft light be connected to the electrical system?. Only through a transformer. Through a relay or directly into the electrical circuit. Only through a battery.

How are the numerous passenger compartment lights controlled on modern aircraft such as the Boeing 777?. Individually by each passenger. By the landing gear control unit. By a central control unit such as the Cabin Service System (CSS).

At 15,000 feet MSL, how does oxygen transfer to the bloodstream change?. It increases to 100 percent of saturation. It drops to 81 percent of saturation. It drops to 50 percent of saturation.

At what altitude must pressure breathing systems be used?. Above 25,000 feet. Above 35,000 feet. Above 40,000 feet.

If oxygen is not being supplied during normal flight conditions, what must the cabin altitude be?. At or below 10,000 feet. At or below 8,000 feet. At or below 6,000 feet.

What happens when sodium chlorate is ignited?. It stops producing oxygen immediately. It produces nitrogen. It produces oxygen as it burns.

Why can a sodium chlorate oxygen generator not be extinguished?. Because it is electrically controlled. Because it requires continuous fuel. Because it continues producing oxygen until it burns out.

How long does a sodium chlorate oxygen generator typically produce oxygen?. 5–10 minutes. 10–20 minutes. 30–40 minutes.

How do on-board oxygen generating systems on military aircraft produce oxygen?. By heating liquid oxygen. By compressing cabin air. By passing turbine-engine bleed air through a sieve that separates oxygen for breathing use.

Why should oxygen cylinders be filled to less than their maximum rated capacity on a cold day?. To reduce the weight of the cylinder. To prevent oxygen from freezing. To allow for pressure increases as the temperature rises.

How is the final flow rate to individual user stations controlled in a continuous-flow gaseous oxygen system?. By a pressure relief valve. By the oxygen cylinder valve. By a calibrated orifice in each mask.

What is the purpose of a portable EDS unit in a continuous-flow oxygen system?. To increase the oxygen pressure in the cylinder. To continuously supply oxygen at maximum flow. To deliver timed pulses of oxygen on demand, saving oxygen normally lost during holding and exhaling.

Where is a portable EDS unit connected?. Between the oxygen cylinder and the pressure reducer. Between the oxygen source and the mask. Between the mask and the cabin air system.

Which five types of valves are commonly found in high-pressure gaseous oxygen systems?. Filler, bypass, selector, mixer, and drain. Filler, check, shutoff, pressure reducer, and pressure relief. Check, selector, transfer, dump, and vent.

What is the purpose of restrictors and variable restrictors in pneumatic systems?. To increase pneumatic pressure. To control the speed of pneumatically operated components. To measure the temperature of the pneumatic system.

What do the pneumatic system transducers send?. A hydraulic signal to the control valves. A mechanical signal to the gauges. An electrical signal to a dual gauge on the pneumatic control panel.

Where are isolation valve control switches located?. Inside the engine compartment. Near the pneumatic control panel and associated controls. Inside the landing gear bay.

What type of emergency pneumatic system interface is commonly used with braking systems?. An emergency pneumatic system replacing the hydraulic system completely. An emergency high-pressure pneumatic system interfaced with a normally hydraulic braking system. A low-pressure pneumatic system connected to the fuel system.

What is the most common source of vacuum for general aviation light aircraft?. A venturi system. An electrically driven pump. A vane-type engine-driven pump.

Where can the vane-type engine-driven vacuum pump be installed?. Only inside the engine oil tank. On the engine accessory drive shaft or belt-driven on piston engines. Only on the landing gear.

On a piston-engine aircraft, what does the engine oil provide for the vacuum pump?. Only electrical insulation. A seal, cooling, and lubrication. Only pressure regulation.

What is a disadvantage of pump and venturi vacuum systems at high altitude?. Air density increases and vacuum becomes excessive. Air density decreases, making vacuum pressures more difficult to achieve. The engine automatically stops producing vacuum.

What type of maintenance is routinely required for pump vacuum systems?. No maintenance is required. Only electrical maintenance. Maintenance of filters, pumps, valves, pipework, and other components.

Why do vacuum systems become less effective as altitude increases?. Because engine oil pressure increases. Because pneumatic pressure becomes excessive. Because air density decreases, making the required vacuum pressure more difficult to achieve.

How often should the water in the system be drained?. Every day. Every week. At least every 3 days.

Why should fresh water be added to the system?. To increase water pressure. To prevent the growth of bacteria. To reduce cabin pressure.

What creates the suction for flushing below 16,000 feet?. The cabin differential pressure. An electric vacuum blower. The engine bleed-air system.

What creates the suction for flushing above 16,000 feet?. An electric vacuum blower. The hydraulic system. The differential pressure between cabin pressure and outside air pressure.

What can happen if the fluid spray is inhaled?. It can improve respiratory function. It can cause temporary hearing loss. It can damage the lungs.

What precaution should be taken during the flushing operation?. The cabin pressure should be increased. Care must be taken to avoid breathing in the fluid spray. The water system should remain pressurized.

What is the main function of onboard maintenance systems?. They monitor the aircraft for faults, record and store fault data, and provide fault information to flight crews and maintenance personnel. They only monitor fuel consumption. They only control the aircraft's navigation systems.

What type of information can onboard maintenance systems electronically store?. Only flight crew communications. Data contained in maintenance manuals, flight manuals, and other publications. Only engine performance data.

How can information gathered by the Central Maintenance Computer (CMC) be transmitted to the ground?. Through the aircraft's weather radar. Through the hydraulic system. Through the ACARS system.

What does ACARS stand for?. Aircraft Control and Reporting System. Aircraft Communications Reporting and Addressing System. Aircraft Communication and Radar System.

What type of system is ACARS?. A hydraulic control system. An electrical power system. A data link system.

Which communication radio does ACARS use?. Only the HF radio. The aircraft's VHF communications radio and, on some aircraft, a SATCOM radio. Only the weather radar.

How are individual system BITE circuits connected to the CMC?. Through hydraulic lines. Through analog pressure lines. Through a digital data bus.

Which type of data bus is commonly used to connect BITE circuits to the CMC?. ARINC 717. ARINC 429. ARINC 825.

What happens if the BITE detects a fault during a test?. The fault is automatically ignored. The aircraft shuts down immediately. An output is generated and sent to the CMC.

What is the Multipurpose Disk Drive Unit (MDDU) capable of doing?. It operates only in automatic mode. It operates only in manual mode. It operates in both automatic and manual modes.

What is Integrated Modular Avionics (IMA)?. A specific avionics navigation system. A design methodology that describes how avionics systems are put together. A dedicated communication system.

What does IMA describe?. Only the functions of individual avionics systems. The aircraft's electrical power distribution. The way avionics systems are integrated and organized.

What does the core system of an IMA architecture use?. A different processor for every avionics function. The same computer processors for many different purposes. Only mechanical control systems.

What is AFDX based upon?. ARINC 429. ARINC 629. IEEE 802.3 Ethernet.

What may be required when replacing an AFDX switch?. Replacement of all LRUs. Replacement of the aircraft wiring. Software reconfiguration.

What is the primary data transfer system used by AIMS?. ARINC 429. ARINC 629. AFDX only.

How many LRUs is the AIMS connected to via ARINC 629?. 24 LRUs. 44 LRUs. 66 LRUs.

What type of data bus does ARINC 629 use?. A unidirectional data bus. A bi-directional data bus. A wireless data bus.

What does a bi-directional data bus allow?. Data to be sent in only one direction. Data to be sent through separate buses only. Data to be sent both ways on the same data bus.

Which modes can the Navigation Display (ND) use?. ILS, GPS, and TCAS. VOR, Plan, and Approach. Heading, Altitude, and Vertical Speed.

What do cabin systems include?. Only systems used for aircraft navigation. Systems used for communication within the cabin, between the cabin and cockpit, passenger entertainment, and passenger communication with the ground. Only systems used for aircraft maintenance.

What is the purpose of In-Flight Entertainment (IFE) systems?. To control the aircraft's engines. To monitor cabin pressure. To provide entertainment for passengers during the flight.

What is a cabin network service?. A hydraulic system used in the cabin. A digital system typically hosted on a server within the aircraft. A mechanical communication system.

What can passengers typically use the cabin network service for?. Only to control their seats. To connect to the internet and access In-Flight Entertainment (IFE). To communicate directly with air traffic control.

What does the “Sterile Cockpit” switch indicate when activated?. That the aircraft is ready for takeoff. That all cabin systems are switched off. That the flight crew does not wish to receive communications except those concerning safety-critical events.

Where can the “Sterile Cockpit” status be indicated?. Only on the cockpit instruments. On the FAP and other cabin indicators. Only on the passenger entertainment screens.

Why is communication with points outside the aircraft useful?. To control the aircraft's landing gear. To allow access to external networks such as the internet and telephone system. To replace the cabin network server.

What system connects the aircraft to external networks?. The cabin lighting system. The IFE system. The aircraft's external communication system.

What types of networks can the aircraft's external communication system connect to?. Only local cabin networks. Ground-based networks or satellite-based networks. Only airport Wi-Fi networks.

What can passengers communicate with through the aircraft's external communication system?. Only other passengers on board. Only the cockpit crew. External services such as the internet and telephone system.

What type of memory is used by computers to store information?. RAM (Random Access Memory). ROM (Read-Only Memory). Cache memory only.

What does EFB stand for?. Electronic Flight Board. Electronic Flight Bag. Electronic Flight Bus.

What type of information can be accessed through EFB databases?. Only engine maintenance data. Aeronautical charts, airport maps and charts with real-time position monitoring, manuals, minimum equipment lists, and logbooks. Only passenger information.

What can EFB systems display in addition to stored databases?. Only text messages. Only aircraft diagrams. Video.

What can airport maps and charts accessed through the EFB provide?. Only airport weather information. Real-time position monitoring. Only runway lighting control.

What type of document can be accessed through the EFB?. Only passenger manifests. Only fuel receipts. Minimum Equipment Lists (MELs).

Who can access the eLogbook?. Only maintenance personnel. Only passengers. Flight crew.

Where can the eLogbook be accessed?. Only while the aircraft is airborne. Only inside the maintenance hangar. On the ground and onboard the aircraft.

What is attached to the nose gear of an aircraft?. Hydraulic brakes. Steering mechanisms. Spoiler actuators.

What replaces the over-center action of the drag brace for support during ground maneuvers?. A mechanical spring. Internal hydraulic locks in the cylinder. A pneumatic accumulator.

During the compression stroke of the landing gear, how does the fluid flow rate behave?. It remains constant. It stops completely. It is not constant.

How are aircraft tires commonly classified?. By their color. By their manufacturer only. By type, according to the United States Tire and Rim Association.

What type of tires are Type VII tires?. Low-pressure tires used on light aircraft. High-performance tires used on jet aircraft. Special tires used only on helicopters.

What is a characteristic of Type VII tires?. They have low load-carrying capability. They are wider than Type III tires. They are inflated to high pressure and have exceptional load-carrying capability.

When should tire pressure normally be checked after a typical landing?. Immediately after landing. After 3 hours, when the tire has cooled to ambient temperature. After 1 hour.

When is cracking in an aircraft tire tread groove generally unacceptable?. When less than 1/8 inch of the ply is exposed. When more than 1/4 inch of the reinforcing or protector ply is exposed. Only when the entire ply is exposed.

What should be done if volatile fluids come into contact with an aircraft tire?. Use only water. Use engine oil to protect the tire. Wash the tire with denatured alcohol followed by soap and water.

What is the most important factor affecting aircraft tire performance and wear?. Tire color. Wheel diameter. Proper inflation.

How many Proximity Sensor Electronic Units (PSEUs) typically receive proximity sensor information?. One. Two. Four.

How is information from the PSEUs typically communicated to aircraft systems?. Through hydraulic lines. Through electrical power cables only. Through ARINC 629 or ARINC 429 data buses.

What material are typical aircraft wheels made from?. Steel only. Lightweight, strong aluminum alloy. Titanium only.

What is the melting temperature of a yellow fuse plug?. 100°C. 150°C. 200°C.

How should personnel approach a wheel assembly?. From the side. From above only. From the front or rear, not broadside.

Why are hard landings a concern for aircraft wheels?. They always cause visible damage. They only affect low-pressure tires. They can produce distortion or cracks that are very difficult to detect, especially in high-pressure forged wheels.

How thick are the rotor and stator discs approximately?. 1/32 inch. 1/8 inch. 1/2 inch.

What are segmented rotor disc brakes especially adapted for?. Low-pressure mechanical brake systems. High-pressure hydraulic power brake systems. Pneumatic emergency systems only.

What is the function of the debooster?. To increase brake pressure above system pressure. To remove all hydraulic pressure from the brakes. To reduce pressure from the control valve to within the working range of the brake assembly.

When does the auto brake system typically apply the brakes automatically?. When the throttles are at maximum thrust. When the aircraft is airborne. When weight is on the wheels and the throttles are at idle or the thrust reversers are activated.