ENGINEERING TEST Flashcards
You lose all electrical power in flight but are able to restore one AC generator. After you restore the generator some of the DC equipment is not working. What is the problem?
The inverter is not working.
The AC generators are producing insufficient power.
Transformer rectifier is not working.
The AC generator frequency is not correct.
Transformer rectifier is not working.
Correct
In this case, you would want to verify the function of the transformer rectifiers. The generator produces AC power and cannot power DC components directly. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.
From front to back, which is the proper order for the following engine components in a modern turbofan aircraft engine?
Diffuser, compressor, combustion, exhaust, turbine.
Compressor, diffuser, combustion, turbine and exhaust.
Combustion, diffuser, compressor, turbine, exhaust.
Turbine, compressor, exhaust, diffuser, combustion.
Compressor, diffuser, combustion, turbine and exhaust.
Correct
The turbine engine process is as follows: Compression, diffusion into the combustion section, combustion, then exhaust across the turbine to continue the process. Energy not used to move the turbine is used as thrust. Reference: Airplane Flying Handbook, Transitioning to Jet Powered Airplanes.
What are slats?
At low AOA they move forward to allow for the aircraft to be slowed more effectively by adding drag.
They improve roll control by increasing the available surface area of the wing.
They deploy from the top of the wing to dump lift and add drag.
At high AOA they move forward creating opening that allows air to flow over upper surfaces delaying airflow separation.
At high AOA they move forward creating opening that allows air to flow over upper surfaces delaying airflow separation.
Correct
Slats are high lift devices that increase wing camber, allowing for flight at higher angles of attack. When they move forward, they also open a slot that allows for free stream air to energize the boundary layer. Reference: Pilot’s Handbook of Aeronautical Knowledge, Flight Controls.
What are the actions if you encounter a compressor stall at a high altitude?
Increase thrust.
Reduce altitude.
Reduce thrust.
Increase altitude
Reduce thrust.
Correct
Engine, or compressor, stalls occur predominantly at low airspeed due to a disruption of airflow across the fan face. Reducing thrust will help clear the stalled condition. Reference: Aerodynamics For Naval Aviators, Turbojet Operating Limitations
How many volts is a modern aircraft DC electrical system?
24.
28.
40.
18.
28.
Correct
Aircraft DC power systems are typically rated for 28 volts. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.
What is the loudest part of a jet engine?
Exhaust.
Compressor.
Inlet.
Turbine.
Exhaust.
Correct
The passage of exhaust gases creates most of the noise associated with jet engines. Reference: Airplane Flying Handbook, Transition to Jet Powered Airplanes.
With a high angle of attack, what is the most (relatively) effective flight control?
Ailerons.
Rudder.
Elevator.
Trim tabs.
Rudder.
Correct
By virtue of its size, the rudder is very effective even at high angles of attack and low airspeed. Reference: Pilot’s Handbook of Aeronautical Knowledge, Flight Controls.
What would you do if you had fluctuating N1, N2 and EGT along with a thumping sound from the engine?
Lower AOA.
Increase AOA.
Reduce altitude.
Increase altitude.
Lower AOA.
Correct
Engine speed fluctuations and thumping noises are indicative of a compressor stall. Lower AOA and reducing thrust should reestablish airflow across the fan face. Reference: Pilot’s Handbook of Aeronautical Knowledge, Aircraft Systems.
What limits turbine engines from developing compressor stalls?
Handling valves.
Turbine inlet guide vanes.
Variable turbine stators.
Compressor bleed valves.
Compressor bleed valves.
Correct
Compressor bleed valves are installed to “spill” excess air away from the compressor. Excess air in the compressor, especially at low speeds, can cause a compressor stall. Reference: Pilot’s Handbook of Aeronautical Knowledge, Aircraft Systems.
What is the theory behind using hydraulic fluid to control flight controls?
Due to its incompressibility it transfers power immediately to flight controls located away from the pump.
Hydraulic fluid is less likely than gas to combust in high-temperature applications.
Due to its compressibility, hydraulic fluid transfers power immediately to the flight controls located away from the pump.
Hydraulic fluid lubricates the flight control junction points.
Due to its incompressibility it transfers power immediately to flight controls located away from the pump.
Correct
Since fluid is not compressible, the pressure of the fluid can be transferred directly to the actuator for the flight control surface. A gas is compressible, making the use of gas undependable for high pressure surface movement applications. Reference: Pilot’s Handbook of Aeronautical Knowledge, Aircraft Systems
With a Pt2 probe iced over, what indications will you get?
A falsely high EPR.
A falsely low EPR.
EPR will read zero
EPR will be unaffected. Only N1 will read lower than normal.
A falsely high EPR.
Heavy aircraft often have leading edge flaps that are used in conjunction with the trailing edge flaps. Their use with:
Spoilers can greatly decrease wing camber and lift. When stowed, leading edge flaps extend over the leading edge of the wing.
Slats can greatly increase wing camber and lift. When extended, leading edge flaps retract into the leading edge of the wing.
Trailing edge flaps can greatly increase wing camber and lift. When stowed, leading edge flaps retract into the leading edge of the wing.
Speed brakes can greatly decrease wing camber and lift. When stowed leading edge flaps retract into the leading edge of the wing.
Trailing edge flaps can greatly increase wing camber and lift. When stowed, leading edge flaps retract into the leading edge of the wing.
Correct
Leading edge flaps, also known as Krueger flaps, can be combined with flaps to increase wing camber and lift. When not in use, they retract into the underside of the leading edge of the wing. Reference: Aerodynamics for Naval Aviators, High Lift Devices.
What instrument is primary for pitch in straight and level flight?
Attitude indicator.
Airspeed indicator.
VSI.
Altimeter.
Altimeter.
PRIMARY FOR BANK IS HEADING INDICATOR
PRIMARY FOR POWER IS AIRSPEED INDICATOR
What does an inverter do?
Converts AC to DC.
Converts DC to AC.
Converts fixed frequency AC to constant frequency AC.
Converts fixed frequency DC to constant frequency DC
Converts DC to AC.
Correct
Inverters are solid state electrical components that convert DC power to fixed frequency AC power. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System
What is the purpose of the APU?
To provide only supplemental bleed air for pressurization at high altitudes.
To provide adequate engine power at high angles of attack.
To provide an emergency source of electricity only.
Provide a source of electrical power when engines are not running or when aircraft isn’t on external power.
Provide a source of electrical power when engines are not running or when aircraft isn’t on external power.
Correct
The APU supplies electrical power to the aircraft when the engines are not running or in the absence of ground power. Reference: Pilot’s Handbook of Aeronautical Knowledge, Aircraft Construction.
Fill in the blanks: Fowler flaps not only _____ the trailing edge of the wing when deployed but also slide _____, effectively _____ the area of the wing.
Raise; forward; decreasing.
Lower; laterally; increasing.
Lower; aft; increasing.
Lower; forward; decreasing.
Lower; aft; increasing.
Correct
Fowler flaps move aft and downward, increasing wing area and camber to increase lift. Reference: Aerodynamics for Naval Aviators, High Lift Devices.
The turbine ignition system:
Needs to be timed to spark during an exact point in the operational cycle.
Does not need to be timed to spark during an exact point in the operational cycle.
Needs to turn on during an exact point in the operational cycle.
Does not need to turn on during an exact point in the operational cycle.
Does not need to be timed to spark during an exact point in the operational cycle.
Correct
The ignition of fuel in the combustion section of a turbine engine is self-sustaining once the process is initiated. Ignitors are only need at engine start. This is simpler than reciprocating engines, which need ignition at timed properly at during each engine rotational cycle. Reference: Aviation Maintenance Technician Handbook – Powerplant (Vol 1), Aircraft Engines.
You are starting a jet engine and a ground person tells you there is fire shooting out of the tailpipe. What would you do?
Cut the fuel and stop the starter.
Cut the fuel and keep motoring the engine.
Continue with the start. This is a normal part of the process.
Continue the start for 30 seconds and see if the fire goes out.
Cut the fuel and keep motoring the engine.
Correct
You would cut the fuel but continue to motor the engine, thereby continuing airflow through the engine to prevent the fire from spreading forward and also helping to remove unburned fuel from the combustion chamber. Reference: Aviation Maintenance Technician Handbook – Powerplant (Vol 2), Engine Fire Protection Systems.
How long should donning a quick don mask take?
10 seconds.
3 seconds.
1 second.
5 seconds.
5 seconds.
Correct
A quick donning oxygen mask must be able to be put on in 5 seconds. Reference: FAR 91.211.Quick-don mask. These masks must demonstrate the ability to be donned
with one hand in 5 seconds or less, while accommodating prescription glasses. Quick-don masks are typically suspended or stored to permit quick and unimpeded access by cockpit crew. These masks are typically rated to altitudes up to 40,000 feet.
You get smoke in the cabin, and you fix the problem. How do you get rid of the smoke?
Decrease cabin pressure differential.
Increase cabin pressure differential.
Keep the cabin pressure differential the same.
Take no action. Smoke will eventually leave via the outflow valve.
Correct
Decrease cabin pressure differential.
By decreasing cabin altitude, you open the outflow valve. This will remove smoke and fumes. Reference: Airplane Flying Handbook, Emergency Procedures.
You are at FL350 in IMC when you experience an electrical failure of your pitot heating system. What do you expect upon descent thru icing?
Airspeed indicator to act like an altimeter.
Airspeed indicator will be frozen.
Airspeed indicator will be at zero.
Airspeed indicator will act opposite of the altimeter.
Airspeed indicator to act like an altimeter.
Correct
In this case, since the pitot tube and it’s associated drain hole ice up, the airspeed indicator acts as a kind of altimeter. As ambient pressure increases as you descend, the additional static pressure within the airspeed indicator pushes back against the lesser ambient pressure from the now blocked drain hole. This results in a decrease in airspeed as you descend. Reference: Instrument Flying Handbook, Flight Instruments.
The basic elements of the accessory section of a turbofan engine are:
The accessory case, which has machined mounting pads for the engine driven accessories, and the gear train, which is housed within the accessory case.
The accessory gearbox, which has machined mounting pads for the engine-driven accessories, and the gear train, which is housed on the accessory case.
The engine starter, auxiliary power unit, oil pump and filter, and the gear train, which is housed within the accessory case.
The engine starter, auxiliary power unit, oil pump and filter, and the gear train, which is housed on the accessory case.
The accessory case, which has machined mounting pads for the engine driven accessories, and the gear train, which is housed within the accessory case.
Correct
The accessory drive train provides the rotational force required to power engine driven components such as the fuel pump, oil pump, generator and hydraulic pump. Reference: Aviation Maintenance Technician Handbook – Powerplant (Vol 1), Aircraft Engines.
You are at FL350 and lose your pitot static and the airspeed readout drops to zero. What would you do?
Fly a known fuel flow and bank angle.
Enter a shallow descent at idle power.
Apply full power until the onset of the high-speed buffet.
Fly known AOA and power settings.
Fly known AOA and power settings.
Correct
Unreliable airspeeds cause the pilots to have to revert to flying known AOAs (pitch attitudes) and power settings. Reference: Instrument Flying Handbook, Flight Instruments.
What type of anti-ice systems do most commercial jets use?
Electrical anti-ice for wings, inlets, probes, ports, windshields, and sensors.
Pneumatic anti-Ice for engine inlets and wings, electrical anti-ice for probes, ports, windshields, and sensors.
Pneumatic boots for engine inlets and wings, electrical anti-ice for probes, ports, windshields, and sensors.
Pneumatic device for all surfaces, probes, ports, windshields and sensors.
Pneumatic anti-Ice for engine inlets and wings, electrical anti-ice for probes, ports, windshields, and sensors.
Correct
Pneumatic anti-ice is used by most jet aircraft to prevent ice formation on critical flight control surfaces. Probes, ports, sensors and windshields are heated electrically. Reference: Pilot’s Handbook of Aeronautical Knowledge, Aircraft Systems.
During engine start, rising EGT and a slower than normal RPM increase is a sign of what?
Hung start.
No light start.
Hot start.
Failed compressor start.
Hot start.
What is trim?
Provides feedback on the yoke to prevent over control.
Moves in the opposite direction of the primary control to relieve control pressure.
Provides a tab by which the flight control is easier to move.
Allows bleed air to enter the engine anti-ice actuator.
Moves in the opposite direction of the primary control to relieve control pressure.
Correct
Trim tabs move in the opposite direction of the control surface, in essence flying the trailing edge into the correct position for a given airspeed. They are used primarily to relieve control forces. Reference: Pilot’s Handbook of Aeronautical Knowledge, Flight Controls.
In an AC electrical system what device converts AC to DC?
Inverter.
Generator.
Transformer rectifier.
Constant speed drive.
Transformer rectifier.
Correct
A transformer rectifier is a two-part process component. The transformer “steps down” the voltage (usually 28 VDC) and the rectifier turns the alternating current to direct current. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.
On climb out there in no pressure differential. What is the problem?
This is a normal operation.
Pressure vessel leak.
The engines aren’t producing adequate thrust.
The gauges are all faulty.
Pressure vessel leak.
Correct
If there is no pressure differential between the cabin and the ambient air, then a pressure leak likely exists. Reference: Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Cabin Environmental Control Systems.
What is the purpose of the flaps?
Permits flight at lower AOAs and higher airspeeds.
Provides only drag without increasing lift.
Permit steep angle of descent without an increase in airspeed.
Allows for increased roll control at slow speed.
Permit steep angle of descent without an increase in airspeed.
Correct
Flaps increase the wing camber and chord and add drag, allowing for steeper approaches at slower airspeeds. Reference: Pilot’s Handbook of Aeronautical Knowledge, Flight Controls
What instrument would not be affected by a pitot static failure?
Altimeter.
Airspeed.
Attitude indicator.
VSI.
Attitude indicator.
Correct
Pitot static instruments include the altimeter, VSI and airspeed indicator. Reference: Instrument Flying Handbook, Flight Instruments.
What shows up better on weather radar: snow, hail, sleet or rain?
Wet hail. Hail is usually covered with a film of water and therefore acts as a huge water droplet giving the strongest of all echoes.
Dry hail. Ice is a highly reflective surface for weather radar.
Rain is the most reflective precipitation type for radar.
Sleet and snow are the most reflective, since they are frozen.
Wet hail. Hail is usually covered with a film of water and therefore acts as a huge water droplet giving the strongest of all echoes.
Correct
Wet hail is the most reflective precipitation that weather radar can depict. Reference: Airborne Weather Radar Limitations, National Weather Service.
Define specific fuel consumption.
Fuel flow in gallons for a given airspeed.
Fuel flow in pounds for a given airspeed.
Fuel flow at a given cruise altitude.
Fuel flow in lbs. per hour at a given power setting.
Fuel flow in lbs. per hour at a given power setting.
Correct
Specific fuel consumption is the amount of fuel burned per hour per unit of thrust (lbs of fuel per hour/pounds of thrust). Reference: Aerodynamics for Naval Aviators, Turbojet Operating Characteristics
is the fuel efficiency of an engine design with respect to thrust output. TSFC may also be thought of as fuel consumption
Where is the greatest air velocity found in a turbine engine?
N1 compressor.
N2 Compressor.
Exhaust.
Exhaust.
Correct
The highest air velocities, and thus the highest energy, is found in the inter-turbine guide vane section of the engine. Reference: Aviation Maintenance Technician Handbook – Powerplant (Vol 1), Aircraft Engines
Why do we use EGT to determine engine performance?
EGT is a direct measurement of the power being produced by the engine
EGT is a direct measure of the amount of fuel being used.
EGT is the only way to measure the performance of a turbine engine.
The limiting factor of a gas turbine engine section is the turbine section.
The limiting factor of a gas turbine engine section is the turbine section.
Correct
The most limiting factor of a gas turbine engine is the temperature of the turbine section, which is indirectly measured by the temperature of the exhaust gases leaving the turbine through the exhaust. Reference: Pilot’s Handbook of Aeronautical Knowledge, Aircraft Systems.
What is the correct sequence for starting turbine engines?
Fuel, ignition, air.
Air, Ignition, Fuel.
Ignition, fuel, air.
Combustion, intake, compression.
Air, Ignition, Fuel.
Correct
First, adequate airflow must exist. Second, ignition must be provided. Third, fuel is provided to the combustion chamber via the fuel nozzles. Reference: Airplane Flying Handbook, Transition to Jet Powered Airplanes.
What is the compressibility of gas versus liquid?
Gas is compressible.
Liquid is compressible.
Neither gas nor liquid are compressible.
Both gas and liquid are compressible.
Gas is compressible.
Correct
Physics states that gasses are compressible, where fluids are not. Reference: Pilot’s Handbook of Aeronautical Knowledge, Aircraft Systems.
When are compressor stalls most likely?
High angle of attack.
Low angles of attack.
High airspeeds.
In cruise.
High angle of attack.
Correct
At higher angles of attack, the airflow into the compressor inlet is more likely to be disturbed. It is this disruption that leads to compressor stall. Reference: Aerodynamics for Naval Aviators, Turbojet Operating Limitations.
What is the best performance for a turbine engine?
High RPM.
Low RPM.
At a moderate RPM.
At low altitude and low airspeed.
High RPM.
Correct
Jet engines operate most efficiently at high RPM, which allows for the maximum inlet pressure. Reference: Aerodynamics For Naval Aviators, Turbojet Operating Characteristics.
An enhanced version of the fowler flap:
Contains an aerodynamic surface that separates from the wing to increase the angle of attack
Contains an aerodynamic surface that is triple-slotted.
Consists of a forward, middle and aft panel that when deployed, slides each the aft panel rearward on tracks as it lowers.
Consists of a forward, middle and aft panel that when deployed, slides each the aft panel forward on tracks as it raises.
Contains an aerodynamic surface that is triple-slotted.
Correct
Enhanced fowler flaps include triple slots in between individual surfaces. This allows the boundary layer at the aft portion of the wing to be energized, increasing lift. Reference: Aerodynamics for Naval Aviators, High Lift Devices.
