Written Prepware Questions (Airframe II)
What is the maximum number of splices permitted between any 2 connectors?
1
A fully integrated autopilot controls the aircraft around how many axes?
3 - roll, yaw, pitch.
The operating mechanism of most hydraulic pressure gauges is what?
A Bourdon tube.
What is a hydraulic fuse?
A device that is open when normal fluid flow is occurring but closes when an excessive rate fluid flow occurs or when excessive amount of flow has occurred. key - just like electric fuses, when current (fluid flow) is too high, it blocks the flow (opens the circuit).
How does the magnetic brake used to stop rotation of an electric motor armature operate?
A friction brake is applied by a spring and released by a magnet.
A CSD unit drives a generator through the use of what?
A variable hydraulic pump and hydraulic motor.
What is used in many aircraft to prevent bubbles in the fuel after it leaves the tank when atmospheric pressure is lower than the fuel vapor pressure?
Boost pumps
How is a shunt wound DC generator connected?
Both fields are shunted across the armature
What is the color code for fire extinguisher lines?
Brown
During ground operation, how is aircraft generator cooling usually accomplished?
By an integral fan mounted on the armature shaft.
How does a radar altimeter determine altitude? What does it indicate?
By transmitting a signal and receiving back a reflected signal. AGL (above ground level)
What is the function of the CRT in an EFIS system?
CRT (cathode ray tube) displays alphanumeric data and representations of aircraft instruments.
What controls the operation of the cabin pressure regulator?
Cabin altitude (cabin air pressure)
How does temperature effect fuel weight?
Cold fuel is heavier per gallon than warm fuel.
How is the inductor-type inverter output voltage controlled?
DC stator field current
What procedure must be followed when refueling aircraft with sweptback wings?
Defuel the outboard tanks first, unless the maintenance manual specifies otherwise.
What prevents a sudden loss of pressurization in the event that there is a loss of the pressurization source?
Delivery air duct check valve. (isolation valve)
What reference would you use to find how aircraft instruments should be marked and graduated?
In the aircraft maintenance manual or flight manual.
What are the cases for electrically operated instruments made of?
Iron or steel.
What does the thermostat circuit do in the operation of a combustion heater?
It alternatively turns the fuel on and off going to the burner. A process known as cycling.
What is the function of the commutator in a generator?
It changes AC to DC as it leaves the armature.
When moving the mixture control on a normally operating engine into the idle cutoff position, what happens to the engine RPM?
It will slightly increase before the engine starts to die. When mixture is moved to the IDLE CUTOFF position, it pass through the fuel/air ratio that produces the best burning. So RPM increases before dropping completely.
If a pilot reports that the brake pedals have excessive travel, what is the probable cause?
Lack of fluid in the brake system.
If an aircraft's constant-pressure hydraulic system cycles more frequently than usual and no fluid leakage is detected and the reservoir is properly filled, what is the most probable cause?
Low accumulator pre-load.
Which section of a turbine engine provides high pressure bleed air to an air cycle machine for pressurization and air-conditioning?
Low or high pressure (stages of the) compressor
Is the vapor pressure of aviation gasolines higher or lower than automotive gasoline?
Lower
The evacuation of a vapor-cycle cooling system removes any water that may be present by...?
Lowering the boiling point of the water and drawing out the vapor.
What is the fixed line mark attached to the compass bowl of a magnetic compass called?
Lubber line
What procedure should you use if you find a vacuum-operated instrument glass loose?
Mark the case and glass with a white slippage mark.
What are the best safeguards against heat buildup in aircraft tires?
Minimum braking, slow taxi speeds, short ground rolls, & proper tire inflation.
What component of a pressurization system prevents the cabin altitude from becoming higher that airplane altitude?
Negative pressure relief valve This may be incorporated into the outflow valve or it may be a separate unit.
Can a fire extinguisher cartridge removed from one discharge valve be used on another discharge valve? Why or why not?
No, the distance the contact point protrudes may vary with each unit and continuity may not exist to ignite the squib.
What test is used to determine the serviceability of an oxygen cylinder?
Pressure test with water (hydrostatic test)
How should a removable rigid fuel tank be inspected for leaks?
Pressurize the tank with air and brush with a soapy solution.
What is the frequency of an alternator dependent upon?
RPM - speed of the alternator.
What is the function of the symbol generator (SG) in an EFIS system?
Receive and process input signals from aircraft and engine sensors and send the data to the appropriate display.
What unit in a vapor-cycle cooling system serves as a reservoir for the refrigerant?
Receiver-dryer.
What flight safety-related advantage does a pressure fueling system provide?
Reduces chance for contamination and reduces danger of static electricity igniting fuel vapors.
Installed radio equipment is protected from damage due to jolts and vibration by what?
Shock mounts.
What type of valve is sued in the brake actuating line to isolate the emergency brake system from the normal power brake control valve system?
Shuttle valve key - the emergency valve
When flags such as NAV, HDG, or GS are displayed on an HSI, what does this indicate?
That the function is inoperative.
What will be the result if the instrument static pressure line becomes disconnected inside a pressurized cabin during cruising flight?
The altimeter and airspeed indicator will both read low.
What would be the effect if the piston return spring broke in a brake master cylinder?
The brakes would drag.
In an operating vapor cycle cooling system, if the two lines connected to the expansion valve are essentially the same temperature, what does this indicate?
The expansion valve is not metering freon properly. There should be a temperature drop downstream from the thermal expansion valve.
When installing an instrument in an aircraft, who is responsible for making sure it is properly marked?
The instrument installer.
What should be done if a strut bottoms after it has been properly serviced?
The strut should be removed, disassembled, and inspected.
Overinflated tires may cause damage to what part of the tire when a hard landing occurs?
The wheel flange
What is one advantage of piston-type hydraulic motors over electric motors?
There is no fire hazard if the motor is stalled.
Which valve installed in a hydraulic system will have the highest pressure setting?
Thermal relief valve.
What is the purpose of the airflow metering aneroid assembly found in oxygen diluter demand regulators?
To regulate airflow in relation to cabin altitude when in the diluter demand position.
After a hydraulic accumulator has been installed and air chamber charged, the main system hydraulic pressure gauge will not show a hydraulic pressure reading until what point?
When fluid has been allowed to flow to the fluid side of the accumulator.
When must the radio station license be displayed in an aircraft equipped with a two-way radio?
When the aircraft is operated outside the US.
What type of icing may occur even when there is no visible moisture present?
carburetor icing
What type of fuel-boost pump separates air and vapor from the fuel before it enters the line to the carburetor?
centrifugal-type pump
What are 2 possible sources of heat for the operation of wing thermal anti-icing systems?
compressor bleed air and aircraft electrical system (for embedded heating elements)
What is the most common cause of false fire warnings in a continuous-loop fire-detection system?
dents, kinks, or crushed sensor sections.
Data transmitted between components in an EFIS are converted into what type of signals?
digital signals.
How are fuel flow transmitters designed to transmit data?
electrically.
Residual voltage is a result of magnetism in what?
field shoes
What is used in many fuel tanks to prevent fuel from flowing away from the boost pump or tank outlet when the aircraft is in a high "G" maneuver?
flapper valves
What type of selector valve is one of the most commonly used in hydraulic systems to provide for simultaneous flow of fluid into and out of a connected actuating unit?
four-port, closed center selector valve.
What 3 kinds of circuit-protection devices are most commonly used in aircraft circuits?
fuses, circuit breakers, and current limiters.
When air samples contain carbon monoxide, portable carbon monoxide detectors containing yellow silica gel will turn which color?
green
What is the principal advantage of the series-wound DC motor?
high starting torque
When adding a rheostat to a light circuit to control the light intensity, how it should be connected with the light?
in series with the light
If there is frost or ice buildup on a vapor-cycle evaporator, what is the most likely cause?
inadequate airflow through the evaporator. There's not enough airflow to transfer heat to the low pressure liquid in the evaporator.
What is used most often to overcome the effect of armature reaction?
interpoles.
Why is the capacitance fluid quantity indicating system more accurate in measuring fuel level than a mechanical type?
it measures by weight instead of volume.
Why should a chemical rain repellant not be used on a dry windshield?
it will restrict visibility This is because has a syrupy consistency and if there's no rain to thin it out it will smear on the windshield.
A fuel system must be designed to prevent fuel vapor ignition caused by what?
lightning.
What do instrument panel shock mounts absorb?
low frequency, high-amplitude shocks.
What protection to wires and cables does conduit provide when used in aircraft installations?
mechanical
If oxygen bottle pressure is allowed to drop below a specified minimum, what could happen? What is that minimum pressure?
moisture can collect in the bottle. 50psi
What is the main cause of contamination in gaseous oxygen systems?
moisture.
What is the purpose of a servo in an autopilot system?
move the control surface as commanded.
When a vapor-cycle cooling system is not in operation, what is an indication that the system is leaking freon?
oil seepage If refrigerant leaks from the system, it is likely to carry some traces of oil in it. Any trace of oil on the outside of the hoses or components is a possible indication of the location of a refrigerant leak.
What is a contaminated oxygen system normally purged with?
oxygen (lol)
What does the turn coordinator show?
rate of turn, roll and yaw.
What should be done if on a periodic check of fire-extinguisher containers, the pressure was not between minimum and maximum limits?
replace the extinguisher container.
What type of centrifugal fuel-booster pump requires a pressure relief valve?
sliding-vane fuel pump
How should the splices be arranged if several are to be located in an electrical wire bundle?
staggered along the length of the bundle.
What is an important factor in selecting aircraft fuses?
that the capacity matches the needs of the circuit.
In a generator, what eliminates any possible sparking to the brush guides caused by the movement of the brushes within the holder?
the brush pigtail
After an ADF antenna is installed, what must be calibrated?
the loop
What is the operating principle of the sensing device used in an autopilot system?
the relative motion between a gyro and its supporting system.
What is one disadvantage of using aromatic aviation fuels?
they deteriorate rubber parts
When may a carbon dioxide (CO2) hand-held fire extinguisher be used on an electrical fire?
when the horn is nonmetallic
What does the magnesyn remote indicating system use as its rotor?
a permanent magnet
What does an autosyn remote indicating system use as its rotor?
an electromagnet
When a landing gear safety switch on a main gear strut closes at liftoff, which system is deactivated?
antiskid system
How long should you wait after a flight before checking tire pressure?
at least 2hrs (3hrs in hot weather).
What does a reciprocating engine manifold pressure gauge indicate when the engine is not operating?
atmospheric pressure.
How many engine driven fuel pumps per engine are required for engines requiring fuel pumps? What FAR can you find this in?
1 fuel pump per engine. 14 CFR 23.
How much clearance from the seat bottom is required when installing radio equipment under a seat?
1 inch with the seat occupied and subjected to maximum downward seat spring deflection.
What is the minimum distance allowed between a fuel tank and the fire wall separating the engine?
1/2 inch
What is the minimum ben radius for an electrical wire bundle?
10 x the outside diameter of the bundle.
Composite oxygen bottles that conform to DOT-E-8162 have a service life of...?
15 years or 10,000 filling cycles whichever occurs first.
How many vents, arranged so that they are not likely to become plugged at the same time, must be used in multiengine fuel systems?
2
What is the maximum amount of time a circuit can be in operation and still be an intermittent duty circuit?
2 min
An emergency locator transmitter (ELT) battery must be capable of furnishing power for signal transmission for at least how many hours?
48hrs
What is the maximum vapor pressure allowable for aircraft fuel?
7 PSI
How would an airspeed indicator be marked to show the best rate-of-climb speed (one engine inoperative)?
A blue radial line.
An O-ring intended for use in a hydraulic system using MIL-H-5606 (mineral base) fluid will be marked with what?
A blue stripe or dot.
What is a power pack?
A self-contained hydraulic system that includes the reservoir, pump, selector valves, & relief valves in one easy-to-service unit.
What type of oxygen system uses the rebreather bag-type mask?
Continuous flow.
A transducer in a fuel pressure system serves what function?
Converts fluid pressure directly through a transmitter to the indicator.
What is normally used to bond noncontinuous stainless steel aircraft components?
Copper jumpers
Where should aircraft defueling be accomplished?
In the open air for good ventilation.
What are the 3 different cabin pressurization modes of operation?
Isobaric Differential Unpressurized
When R-12 is passed over an open flame what happens?
It changes to phosgene gas.
A transmitter in a fuel pressure warning system serves what function?
It converts fluid pressure to an electrical signal. This electrical signal turns on a warning light or flashes a warning on the annunciator panel.
What is the general purpose of an aircraft transponder?
It receives an interrogation signal from a ground station and automatically sends a reply back.
What is the function of an absolute pressure regulator in a pneumatic power system?
It regulates the compressor inlet air to provide a stabilized source of air for the compressor. key - regulates compressor inlet air.
What should be done when a diode is checked for an open or short circuit?
It should be disconnected from the circuit.
How can it be determined if a transformer winding has some of its turns shorted together?
It will get hot in normal operation. This is due to excessive current flow.
What is the cause of generator brush arcing?
Low spring tension.
What condition would most likely cause excessive fluctuation of the pressure gauge when the hydraulic pump is operating?
Low supply of fluid.
In a typical high-pressure pneumatic system, if the moisture separator does not vent accumulated water when the compressor shuts down, what is the likely cause?
Malfunctioning solenoid dump valve.
If fluid is added to a reservoir in a constant pressure hydraulic system while the system is pressurized, what will result?
The fluid level will increase when system pressure is reduced.
Where is fuel pressure taken for the pressure warning signal on most aircraft engines?
The fuel pressure line of the carburetor.
After installation of a rebuilt hydraulic hand pump, it is found that the handle cannot be moved in the pumping direction (pressure stroke). What is the most likely cause?
The outport check valve is incorrectly installed.
If an aircraft hydraulic system requires mineral base hydraulic fluid, but phosphate ester base hydraulic fluid is used, what will be the effect on the system? How do you fix it?
The system's contaminated, fluids will not mix, and the seals will fail. To fix, flush and replace all seals and filters.
What component in a vapor-cycle cooling system would most likely be at fault if a system will not take a freon charge?
Thermal expansion valve It only takes a tiny particle of dirt or other contaminant to stop the flow of refrigerant through the tiny orifice of this valve.
What maintains normal windshield temperature control in an electrically heated windshield system?
Thermistors Thermistor is a special form of electrical resistor whose resistance is a function of its temperature.
What is the function of a display controller in an EFIS system?
To allow the pilot to select the appropriate system configuration for the current flight situation.
Why do most aircraft tire manufacturers recommend that the tubes in newly installed tires be first inflated, fully deflated, and then reinflated to the correct pressure?
To allow the tube to position itself correctly inside the tire.
What is the purpose of a diaphragm in a vane-type fuel pump?
To compensate fuel pressures to altitude changes. It keeps fuel pressure at a constant amount higher than the pressure of the ambient air.
What is the purpose of restrictors in hydraulic systems?
To control the rate of movement of hydraulically operated mechanisms. key - think extending land gear, you wouldn't want it to slam down every time, you'd want it to extend steadily.
What are chines used for on some aircraft tires?
To deflect water away from the fuselage.
What is the purpose of the sequence valve in hydraulic retractable landing gear systems?
To ensure proper operation of the landing gear and gear doors in the proper order.
A sleeve, spacer, or bumper ring is incorporated in a landing gear oleo shock strut for what purpose?
To limit the extension stroke.
Why is it necessary to vent all aircraft fuel tanks?
To limit the pressure differential between the tank and the atmosphere.
What is the purpose of a fuel tank vent?
To maintain atmospheric pressure on top of the fuel and provide proper fuel flow from the tank to the engine.
What is the purpose of the torque links attached to the cylinder and piston of a landing gear oleo strut?
To maintain correct wheel alignment.
What is the purpose of a sub cooler in a vapor-cycle cooling system?
To prevent premature vaporization. This device cools the refrigerant as it leaves the receiver-dryer.
What is the primary function of the flap overload valve?
To prevent the flaps from being lowered at airspeeds that would impose excessive structural loads.
A loud hammering noise in a hydraulic system having an accumulator usually indicates what?
Too low or no preload in the accumulator.
Turbine engine exhaust gas temperatures are measured with what? What about for Reciprocating engines?
Turbine: alumel/chromel Reciprocating: iron/constantan
What prevents a rapid extension of an oleo shock strut after initial compression resulting from a landing impact?
Various types of valves or orifices are used which restrict the reverse fluid flow.
What are the characteristics of MIL-H-7644 hydraulic fluid?
Vegetable base Blue color Will burn Natural rubber seals
In what position should the bottle be placed when adding liquid freon to a vapor-cycle cooling system?
Vertical with the outlet at the bottom.
What is the internal resistance of a fluid which tends to prevent it from flowing called?
Viscosity
What should be used to remove flux from an aluminum tank after welded repairs?
Wash the inside and outside with water, then dip in a 5% solution of sulfuric or nitric acid.
If an airplane equipped with master cylinders and single-disk brakes has excessive brake pedal travel, but the brakes are hard & effective, what is the probable cause?
Worn brake linings.
At what speed does an antiskid system automatically deactivate?
approximately below 20mph.
When bending coaxial cable, what should the bend radius be?
at least 10 times the diameter of the cable
What are CSD driven generators usually cooled by?
oil spray CSD - constant speed drive
Where are aircraft pressure fueling systems instructional procedures normally placarded?
on the fuel control panel access door.
What is a Bourdon tube instrument used to indicate?
pressure and/or temperature.
What device in a hydraulic system with a constant-delivery pump allows circulation of the fluid when no demands are on the system?
pressure regulator
What unit would be adjusted to change the fuel pressure warning limits?
pressure-sensitive mechanism
When purging a freon air-conditioning system, it is important to release the charge at a slow rate. What is the reason for the slow-rate discharge?
prevent excessive loss of refrigerant oil.
What is the function of the gasket or sealant used between the antenna mast and fuselage skin?
prevents the entry of moisture.
What should bonding connections be tested for?
resistance value, it should be no more than 0.003ohms
Why does the Fenwall fire-detection system use spot doctors wired in parallel between 2 separate circuits?
so that a short can exist in either circuit without causing a false fire warning.
Why do some electric motors have 2 sets of field windings wound in opposite directions?
so that the motor can be operated in either direction.
What does arcing in an electrically heated windshield panel indicate a breakdown of?
the conductive coating.
The nominal rating of electrical switches refers to what?
the continuous current rating with the contacts closed.
What side of the circuit is the pin section of an AN/MS connector installed on?
the ground side This minimizes chances of a short circuit between a connector and ground when the connectors are separated.
How is fuel jettisoning usually accomplished?
through a common manifold and outlet in each wing (typically with boost pumps)
If it is necessary to adjust several pressure relief valves in a hydraulic system, what particular sequence, if any, should be followed?
Adjust the units with the highest pressure settings first. If the valves with the lower pressure settings are adjusted first, you will never be able to reach the pressure required for the higher setting.
How can it be determined that a vapor-cycle cooling system is charged with the proper amount of freon?
Air bubbles in the sight glass disappear.
Chattering of the hydraulic pump during operation is an indication of what?
Air in the pump.
In a freon vapor-cycle cooling system, where is cooling air obtained for the condenser?
Ambient air This ambient air removes the heat the passes through the condenser, this loss of heat causes the refrigerant to condense from a vapor into a liquid.
On an air valve core stem, what indicates high pressure type?
An embossed letter "H"
Entrained water in aviation turbine fuel is a hazard because of its susceptibility to freezing as it passes through the filters. What are common methods of preventing this hazard?
Anti-icing fuel additives and fuel heater (heat exchanger)
In a combustion heater, combustion air system, what prevents too much air from entering the heaters as air pressure increases?
Either a combustion air relief valve or differential pressure regulator. Combustion-air relief valve is located in the line leading from the ram intake air duct and is spring-loaded to dump excess air into the cabin-heater exhaust-gas stream. The differential pressure regulator is also located in the combustion-air intake line but controls the amount of air reaching the combustion chamber.
To what depth is the mica insulation between the commutator bars of a dc generator undercut?
Equal to the width of the mica.
How often should a standard weight high-pressure oxygen cylinder be hydrostatically tested?
Every 3 years
Many brake types can be adapted to operate mechanically or hydraulically. Which type is not adaptable to mechanical operation?
Expander tube type They depend on fluid inside the tube for their application.
What regulations cover the requirements for fuel jettisoning?
FAR 23, 25, and CAM 4b.
What provides manual maneuverability of the aircraft while the autopilot is engaged?
Flight controller.
On modern large aircraft, what electronic device typically monitors flight parameters and performs autopilot functions?
Flight management computer (FMC)
Where can information be obtained about the compatibility of fire-resistant hydraulic fluid with aircraft materials?
Fluid manufacturer's technical bulletins.
What should be used to melt the ice in a turbine engine if the compressor is immobile because of ice?
Hot air
Why can only one antenna be used for the radio range and standard broadcast bands in light aircraft?
because the 2 ranges are close together.
What is the best means to use when removing wet snow from an aircraft?
brush or squeegee
How is an anti skid braking system generally armed?
by a switch in the cockpit.
How is the output of an alternator regulated?
by controlling the voltage output of the DC exciter.
How is a pneumatic (reed) type stall warning system activated?
by negative air pressure.
How should you determine the amount of oxygen in a portable, high-pressure cylinder?
by reading the pressure gauge mounted on the cylinder.
How is the outlet fuel pressure regulated on a submerged, single-speed, centrifugal-type fuel pump?
by the pump's design and internal clearances.
How are smoke detectors classified?
by their method of detection
How do static inverters change DC to AC?
by using an oscillator.
When charging after evacuation, the low-pressure gauge fails to come out of a vacuum, what is indicated?
Blockage in the system. When charging a vapor-cycle system after it's been evacuated, refrigerant is put into the high side of the system. If the gauge on the low side fails to come out of vacuum, there is blockage in the system and the low side is not receiving any refrigerant.
How may the antiknock characteristics of a fuel be improved?
By adding a knock inhibitor (such as tetraethyl lead).
The braking action of a Cleveland disk brake is accomplished by compressing a rotating brake disk between 2 opposite brake linings. How is equal pressure on both sides of the rotating disk assured?
By allowing the caliper to float to automatically equalize as pressure is applied to the rotor.
How can damage to long lengths of electrical cable to be used in a rigid conduit be reduced when pulled through the conduit?
By dusting the cable with powdered soapstone, tire talc, or regular talcum powder.
How would you repair an out-of-tolerance toe-in condition of main landing gear wheels if determined not to be the result of bent or twisted components?
By inserting, removing, or changing location of washers or spacers at the center pivotal point of the scissor torque links.
How can a worn hydraulic pump shaft seal normally be detected?
By the presence of hydraulic fluid around the pump mounting pad. Hydraulic pumps have a shaft seal vented into a compartment in the pump and drained overboard. If the pump shaft seal leaks, hydraulic fluid will drip out of the overboard drain line.
How would the air pressure charge in the accumulator be determined if the engine is inoperative, but the system still has hydraulic pressure?
Operate a hydraulic unit slowly and note the pressure at which a rapid pressure drop begins as it goes towards zero. The last pressure indicated before pressure suddenly drops to zero is the pressure of the air in the accumulator.
A flexible sealing element subject to motion is what?
Packing Gasket is a flexible sealing element not subject to motion.
A hydraulic pump converts fluid pressure into what type of motion?
Rotary motion.
if 2 actuating cylinders which have the same crass sectional area but different lengths of stroke are connected to the same source of hydraulic pressure they will exert...?
Same amount of force & move at same rate of speed, but take a different amount of time to reach their full stroke.
In which control element of an autopilot is an attitude indicator?
Sensing
What are the 3 basic types of DC motors?
Series, shunt and compound.
What type of oil is suitable for use in a vapor-cycle cooling system?
Special high grade refrigeration oil. Oil specified in the aircraft service manual.
What is one main disadvantage of Skydrol hydraulic fluid? What is one main advantage?
disadvantage: Its susceptibility to contamination from moisture in the atmosphere. advantage: It has a wide operating temperature range.
What component connects vacuum to the deicer boots when the system is not in operation to hold the boots tightly against the leading edges in flight?
distributor valve
What controls the inflation sequence in a pneumatic deicer boot system?
distributor valve
How is a synchro transmitter connected to a synchro receiver?
electrically with wires.
What type of remote-reading fuel quantity indicating system has several probes installed in each fuel tank?
electronic
Which aircraft fuel quantity indicating system incorporates a signal amplifier?
electronic
If a bladder type fuel tank is to be left empty for an extended period of time, what should the inside of the tank should be coated with?
engine oil
Why are magnetic compass bowls filled with liquid?
to dampen oscillations in the float.
Why are the tubes in deicer boots alternately inflated?
to keep disruption of airflow at a minimum.
What is the purpose of the selection of derated switches for know continuous load current applications?
to obtain reasonable switch efficiency and service life.
What is the primary purpose for balancing aircraft wheel assemblies?
to prevent heavy spots and reduce vibration.
