Podcast
Questions and Answers
What happens to the flow of a positive displacement swash plate pump when the swash plate is perpendicular to the axis of the pump?
What happens to the flow of a positive displacement swash plate pump when the swash plate is perpendicular to the axis of the pump?
- The flow is zero. (correct)
- The flow is unpredictable.
- The flow is maximum.
- The flow is reversed.
What moves the swash plate away from the minimum stroke position in a fuel pump?
What moves the swash plate away from the minimum stroke position in a fuel pump?
- Increased servo pressure.
- A spring. (correct)
- Pump delivery pressure.
- Reduced inlet pressure.
At what condition is the burner fuel flow at maximum?
At what condition is the burner fuel flow at maximum?
- At altitude.
- Below I.S.A. sea level.
- I.S.A. sea level. (correct)
- 10°C above I.S.A. sea level.
How is servo pressure, used to control fuel pump 'Swash Plate' angle, obtained?
How is servo pressure, used to control fuel pump 'Swash Plate' angle, obtained?
What would be the effect on the engine if the B.P.C half ball valve in the servo line sticks open?
What would be the effect on the engine if the B.P.C half ball valve in the servo line sticks open?
What is the purpose of an A.C.U fitted to a gas turbine engine?
What is the purpose of an A.C.U fitted to a gas turbine engine?
What happens to the pump output if fuel pump servo pressure is reduced?
What happens to the pump output if fuel pump servo pressure is reduced?
What is the function of the swash plate in a fuel pump?
What is the function of the swash plate in a fuel pump?
What is the purpose of the Barometric Pressure Controller in a gas turbine engine fuel system?
What is the purpose of the Barometric Pressure Controller in a gas turbine engine fuel system?
What must be done after the fuel control unit has been replaced on an aircraft gas turbine engine?
What must be done after the fuel control unit has been replaced on an aircraft gas turbine engine?
What is the function of a kinetic valve in a gas turbine engine fuel system?
What is the function of a kinetic valve in a gas turbine engine fuel system?
What is the effect of increasing air intake pressure on fuel flow to the burners?
What is the effect of increasing air intake pressure on fuel flow to the burners?
What is the purpose of the attenuator in a gas turbine engine fuel system?
What is the purpose of the attenuator in a gas turbine engine fuel system?
Why is a hydromechanical governor fitted to a gas turbine engine fuel pump?
Why is a hydromechanical governor fitted to a gas turbine engine fuel pump?
What is the normal fuel-to-air ratio for successful combustion in a gas turbine engine?
What is the normal fuel-to-air ratio for successful combustion in a gas turbine engine?
What influences the operation of an automatic fuel control unit on a turbojet engine?
What influences the operation of an automatic fuel control unit on a turbojet engine?
What happens to specific fuel consumption at altitude?
What happens to specific fuel consumption at altitude?
During stabilized running conditions, the spill or half-ball valve is typically?
During stabilized running conditions, the spill or half-ball valve is typically?
What is the purpose of the L.P. pump?
What is the purpose of the L.P. pump?
How are the fuel pump plungers lubricated?
How are the fuel pump plungers lubricated?
Which forces control the maximum RPM governor in a non-hydromechanical swashplate type of pump?
Which forces control the maximum RPM governor in a non-hydromechanical swashplate type of pump?
Why do the holes in the body of the duple burner provide air to the shroud around the burner head?
Why do the holes in the body of the duple burner provide air to the shroud around the burner head?
What does a fuel heater prevent?
What does a fuel heater prevent?
What is the main purpose of the Barometric Pressure Control?
What is the main purpose of the Barometric Pressure Control?
What is the function of the E.E.C. on a FADEC engine?
What is the function of the E.E.C. on a FADEC engine?
During normal running conditions, is combustion?
During normal running conditions, is combustion?
What occurs when the swash plate of a positive displacement swash plate pump is perpendicular to the axis of the pump?
What occurs when the swash plate of a positive displacement swash plate pump is perpendicular to the axis of the pump?
What is the primary cause of surge in a jet engine?
What is the primary cause of surge in a jet engine?
What happens when the channel reset is activated on a FADEC engine?
What happens when the channel reset is activated on a FADEC engine?
How is servo pressure obtained in a jet engine fuel system?
How is servo pressure obtained in a jet engine fuel system?
What happens to the maximum RPM of a turbine engine when the fuel specific gravity decreases and the engine is fitted with an uncompensated fuel governor?
What happens to the maximum RPM of a turbine engine when the fuel specific gravity decreases and the engine is fitted with an uncompensated fuel governor?
What is the primary function of the fuel control unit in a jet engine?
What is the primary function of the fuel control unit in a jet engine?
What limits the maximum RPM of a turbine engine?
What limits the maximum RPM of a turbine engine?
Why is it necessary to control fuel supply during rapid acceleration?
Why is it necessary to control fuel supply during rapid acceleration?
What type of fuel control unit is most commonly used in modern jet engines?
What type of fuel control unit is most commonly used in modern jet engines?
What is the purpose of the kinetic valve in a fuel pump?
What is the purpose of the kinetic valve in a fuel pump?
What is the position of the swash plate in a fuel pump when static?
What is the position of the swash plate in a fuel pump when static?
During stabilized running conditions, the spill or half ball valve is?
During stabilized running conditions, the spill or half ball valve is?
What is the primary function of the high-pressure fuel pump in a gas turbine engine aircraft?
What is the primary function of the high-pressure fuel pump in a gas turbine engine aircraft?
What is the position of the pressurization valve and the dump valve in a jet engine fuel system when the engine is shut down?
What is the position of the pressurization valve and the dump valve in a jet engine fuel system when the engine is shut down?
Which of the following air mixtures weighs the most?
Which of the following air mixtures weighs the most?
What does a mixture ratio of 11:1 normally refer to?
What does a mixture ratio of 11:1 normally refer to?
What is the primary purpose of trimming a turbine engine fuel control unit?
What is the primary purpose of trimming a turbine engine fuel control unit?
What type of fuel control is used on most of today's turbine engines?
What type of fuel control is used on most of today's turbine engines?
When is the trimming of a turbine engine most accurate?
When is the trimming of a turbine engine most accurate?
What signal does an H.M.U receive?
What signal does an H.M.U receive?
When trimming a turbine engine, the fuel control is adjusted to:
When trimming a turbine engine, the fuel control is adjusted to:
What is the function of a supervisory electronic engine control (E.E.C)?
What is the function of a supervisory electronic engine control (E.E.C)?
What causes the fuel divider valve to open in a turbine engine duplex fuel nozzle?
What causes the fuel divider valve to open in a turbine engine duplex fuel nozzle?
What is the safety backup available for the engine fuel flow if the valve on a vane type fuel flow measuring device becomes stuck?
What is the safety backup available for the engine fuel flow if the valve on a vane type fuel flow measuring device becomes stuck?
What is the primary advantage of the duplex fuel nozzle used in many turbine engines?
What is the primary advantage of the duplex fuel nozzle used in many turbine engines?
What is the purpose of the flow divider in a turbine engine duplex fuel nozzle?
What is the purpose of the flow divider in a turbine engine duplex fuel nozzle?
Which of the following turbine fuel filters has the greatest filtering action?
Which of the following turbine fuel filters has the greatest filtering action?
Where is the engine fuel shutoff valve usually located?
Where is the engine fuel shutoff valve usually located?
If a FADEC loses its ADC input, what will it do in the short term?
If a FADEC loses its ADC input, what will it do in the short term?
The primary purpose of an E.E.C is to:
The primary purpose of an E.E.C is to:
When both FADEC channels are healthy, what happens?
When both FADEC channels are healthy, what happens?
What is the purpose of the LP fuel pump?
What is the purpose of the LP fuel pump?
What is the primary function of a FADEC system?
What is the primary function of a FADEC system?
What type of filter is typically used on the inlet side of a fuel pump?
What type of filter is typically used on the inlet side of a fuel pump?
What happens to the pressure drop across the Fuel Control Unit throttle orifice when the throttle is selected to increase power?
What happens to the pressure drop across the Fuel Control Unit throttle orifice when the throttle is selected to increase power?
What action does the E.E.C take when it senses a fault on the engine?
What action does the E.E.C take when it senses a fault on the engine?
What does the E.E.C control in-flight?
What does the E.E.C control in-flight?
What does a FADEC system not have?
What does a FADEC system not have?
What prevents fuel from spilling out of fuel tank vents during aerobatic maneuvers?
What prevents fuel from spilling out of fuel tank vents during aerobatic maneuvers?
What is the purpose of the low-pressure fuel pump in a FADEC system?
What is the purpose of the low-pressure fuel pump in a FADEC system?
Where would you disconnect the system to carry out flow checks after a bag tank replacement?
Where would you disconnect the system to carry out flow checks after a bag tank replacement?
What happens when Channel A fails to receive information from a sensor in a FADEC system?
What happens when Channel A fails to receive information from a sensor in a FADEC system?
What is the purpose of a silver strip on a fuel filter?
What is the purpose of a silver strip on a fuel filter?
How is fuel flow controlled in a FADEC engine with a hydromechanical fuel system?
How is fuel flow controlled in a FADEC engine with a hydromechanical fuel system?
What should the RPM be set to on approach for maximum acceleration?
What should the RPM be set to on approach for maximum acceleration?
What is the primary purpose of cross-feeding fuel from one tank to another?
What is the primary purpose of cross-feeding fuel from one tank to another?
What type of pressure controls the swash plate in the fuel pump of an axial flow gas turbine engine?
What type of pressure controls the swash plate in the fuel pump of an axial flow gas turbine engine?
What happens if the air data inputs to the FADEC E.C.U fail?
What happens if the air data inputs to the FADEC E.C.U fail?
Why are the end fittings on a fuel non-return valve normally of different sizes?
Why are the end fittings on a fuel non-return valve normally of different sizes?
What components make up a FADEC system?
What components make up a FADEC system?
What does a fuel heater prevent in a FADEC system?
What does a fuel heater prevent in a FADEC system?
What type of sensors does the E.E.C receive signals from?
What type of sensors does the E.E.C receive signals from?
When re-light is required in flight on a FADEC engine, what happens to the igniter selection?
When re-light is required in flight on a FADEC engine, what happens to the igniter selection?
When does the E.E.C channel change over occur?
When does the E.E.C channel change over occur?
Where is the fuel heater located in the fuel system?
Where is the fuel heater located in the fuel system?
What is the combined output of all the scavenge pumps in a lubrication system compared to the pressure pump output?
What is the combined output of all the scavenge pumps in a lubrication system compared to the pressure pump output?
What is the primary power source for the E.E.C?
What is the primary power source for the E.E.C?
What happens when the knife-edge blade in a kinetic valve is fully in?
What happens when the knife-edge blade in a kinetic valve is fully in?
What is the purpose of the kinetic valve in a gas turbine engine fuel system?
What is the purpose of the kinetic valve in a gas turbine engine fuel system?
What is the purpose of the acceleration control unit?
What is the purpose of the acceleration control unit?
In a FADEC system, what does the E.E.C measure along with RPM?
In a FADEC system, what does the E.E.C measure along with RPM?
What is the purpose of trimming in a gas turbine engine?
What is the purpose of trimming in a gas turbine engine?
How are the power supply windings for channel A and Channel B wound in a FADEC system?
How are the power supply windings for channel A and Channel B wound in a FADEC system?
What happens if an Engine FADEC system loses air-data permanently?
What happens if an Engine FADEC system loses air-data permanently?
What is the main purpose of the fuel boost pumps in a gas turbine engine?
What is the main purpose of the fuel boost pumps in a gas turbine engine?
What is the function of baffles in a rigid fuel tank?
What is the function of baffles in a rigid fuel tank?
What is the forward idle setting of the thrust lever resolver angle?
What is the forward idle setting of the thrust lever resolver angle?
How are fuel pumps cooled?
How are fuel pumps cooled?
What happens to the fuel flow governor when the engine is at altitude?
What happens to the fuel flow governor when the engine is at altitude?
Study Notes
Swash Plate Pump
- If the swash plate is perpendicular to the axis of the pump, the flow will be zero
- The swash plate angle is controlled by servo pressure, which is obtained from pump delivery pressure through variable restrictions
- A spring moves the swash plate away from the minimum stroke position
Fuel System
- The burner fuel flow is at maximum at sea level (ISA)
- Fuel flow responds to mass airflow rate through the engine during aircraft acceleration
- Fuel flow is increased at a controlled rate during acceleration to prevent surge and the risk of flame-out
- The barometric pressure controller (BPC) controls fuel pump output in relation to the pressure variation at the intake
Fuel Pump
- The high-pressure fuel pump is fitted in a gas turbine engine aircraft to provide the majority of the fuel pressure to the engine
- The low-pressure pump prevents cavitation of the high-pressure fuel pump
- The fuel pump plungers are lubricated by the fuel itself
Governor
- The hydromechanical governor is fitted to a gas turbine engine fuel pump to enable the engine to operate over a wide range of fuel specific gravities
- The governor controls the maximum RPM of the engine by reducing the fuel pump stroke when maximum RPM is reached
Fuel Control Unit (FCU)
- The FCU is trimmed to obtain maximum thrust output when desired
- The FCU is adjusted to set idle RPM and maximum speed or EPR
- Trimming is most accurate in no wind and low moisture conditions
Electronic Engine Control (EEC)
- The EEC receives engine operating information and adjusts a standard hydromechanical fuel control unit to obtain the most effective engine operation
- The EEC is a system that controls engine operation according to ambient temperature, pressure, and humidity
FADEC System
- FADEC (Full Authority Digital Engine Control) system has electronic control of the hydro-mechanical fuel control unit in all modes
- Active control switchover occurs on engine start-up only
- Channel reset selects standby, which becomes active on the next start
Fuel Nozzle
- The duplex fuel nozzle provides better atomization and uniform flow pattern
- The flow divider in a turbine engine duplex fuel nozzle creates the primary and secondary fuel supplies
- The valve on a vane type fuel flow measuring device becomes stuck, and a differential pressure bypass valve is the safety backup available for the engine fuel flow### Engine Fuel Shutoff Valve
- Located downstream of the engine driven fuel pump
FADEC System
- Consists of H.M.U, sensors, and an E.E.C
- Primary purpose is to save fuel, reduce crew workload, and reduce maintenance costs
- Receives primary power from a separate permanent magnet alternator
- E.E.C measures pressure and temperature along with RPM
- Can change digital inputs into analogue format to provide glass cockpit information and reduce flight crew workload
- Has an automatic starting capability
- Does not have automatic control of engine fire bottles
Throttle and Fuel Control
- Throttle position is controlled by the crew or autothrottle
- Fuel flow is controlled by the E.E.C in flight
- Trimming is adjusting idle speed and maximum thrust
- Fuel trimmer unit is adjusted automatically at altitude
FADEC Channels
- Both channels are operating, but either one can be in command if they are both healthy
- If a channel fails to receive information from a sensor, it will take the information from the other channel
- If all air data input fails, the E.C.U reverts to an alternate (Fail-safe) mode
Engine Performance
- Optimized performance is the reason FADEC was introduced
- FADEC ensures efficiency is always maximum
Fuel System
- Engine fuel pump has a wire mesh filter
- Pressure drop across the Fuel Control Unit throttle orifice drops then increases due to increasing pump output
- Fuel boost pumps are cooled using fuel
- Main purpose of the fuel boost pumps is to provide fuel pressure to both engine pumps
Sensors and Valves
- Silver strip on a fuel filter detects sulphur in fuel
- Baffles in a rigid fuel tank prevent surge
- End fittings on a fuel non-return valve are different sizes to prevent incorrect installation
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of positive displacement pumps and burners, including swash plate pumps and fuel flow. This quiz covers key concepts and principles related to these mechanical systems.
