15.11 Fuel Systems (Level 1, 4 Questions) Flashcards by Dylan Sinclair

What could happen if the fuel flow becomes excessive in a gas turbine engine?

a) The turbine blades might freeze
b) A compressor stall or rich blowout could occur
c) The engine might accelerate too quickly

b) A compressor stall or rich blowout could occur

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What are the three categories of gas turbine engine fuel control systems?

a) Hydromechanical, manual, and digital systems
b) Hydromechanical, hydromechanical/electronic, and FADEC
c) Manual, automatic, and semi-automatic systems

b) Hydromechanical, hydromechanical/electronic, and FADEC

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How many categories of gas turbine engine fuel control systems are there?

a) Two
b) Three
c) Four

b) Three

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What is the key advantage of the hydromechanical/electronic fuel control system?

a) It operates entirely without electronics.
b) It can function as both a hydromechanical and an electronic control.
c) It eliminates the need for servo motors in fuel control.

b) It can function as both a hydromechanical and an electronic control.

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What enables FADEC to have complete control over the engine?

a) Manual pilot inputs and traditional controls.
b) Electronic sensors and outputs that meter fuel flow.
c) Hydromechanical backups and emergency overrides.

b) Electronic sensors and outputs that meter fuel flow.

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What is the primary goal of all turbine engine fuel control systems?

a) To match the power requested by the flight crew through precise fuel scheduling.
b) To limit engine thrust regardless of fuel delivery.
c) To sense weather conditions and automatically adjust thrust.

a) To match the power requested by the flight crew through precise fuel scheduling.

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What are the two sections of a hydromechanical fuel control system?

a) Speed sensing and pressure monitoring
b) Computing and metering
c) Electronics and hydraulics

b) Computing and metering

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What differentiates a pure hydromechanical fuel control system from other types?

a) It uses electronic sensors to assist fuel flow computation.
b) It has no electronic interface and relies solely on mechanical components.
c) It operates only during high engine speeds.

b) It has no electronic interface and relies solely on mechanical components.

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What is a drawback of hydromechanical fuel control systems compared to electronic controls?

a) They cannot sense engine speed.
b) Their fuel metering is less accurate.
c) They are too complex to operate.

b) Their fuel metering is less accurate.

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What advancement improved the hydromechanical fuel control system?

a) Adding a fuel shut-off section
b) Combining with an electronic control system
c) Using atomised fuel delivery

b) Combining with an electronic control system

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What device adjusts the fuel flow in a hydromechanical/electronic fuel control system?

a) Hydromechanical assembly
b) Fuel shut-off valve
c) Electronic Engine Control (EEC)

c) Electronic Engine Control (EEC)

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What is the purpose of the vane fuel pump in the engine fuel system?

a) To provide low-pressure fuel for the engine
b) To deliver high-pressure fuel to the control system
c) To bypass excessive fuel to the combustion chamber

b) To deliver high-pressure fuel to the control system

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What happens when the pressure drop across the fuel filter is excessive?

a) The filter automatically cleans itself
b) The fuel bypasses the filter via a bypass valve
c) The engine shuts down to prevent damage

b) The fuel bypasses the filter via a bypass valve

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What does FADEC stand for?

a) Fuel Automatic Digital Electronic Control
b) Full Authority Digital Electronic Control
c) Fast Action Digital Engine Control

b) Full Authority Digital Electronic Control

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Does the FADEC system have a hydromechanical backup?

a) Yes, it has a full hydromechanical backup
b) No, it does not have a hydromechanical backup
c) It depends on the engine type

b) No, it does not have a hydromechanical backup

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How does the FADEC system control fuel flow?

a) Manually by the pilot
b) By using electronic sensors and adjusting the fuel metering valve through the EEC
c) By a mechanical linkage connected to the throttle

b) By using electronic sensors and adjusting the fuel metering valve through the EEC

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What is the primary component of the FADEC engine fuel control system?

a) Fuel metering valve
b) Electronic Engine Control (EEC)
c) Throttle lever

b) Electronic Engine Control (EEC)

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How many electronic channels does the EEC have?

a) One
b) Two (A and B)
c) Three

b) Two (A and B)

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Where is the EEC usually located?

a) In the cockpit
b) In a cool area of the engine nacelle
c) Inside the fuel tank

b) In a cool area of the engine nacelle

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What kind of memory does the EEC contain for storing performance and maintenance data?

a) Only volatile memory
b) Only non-volatile memory
c) Both volatile and non-volatile memory

c) Both volatile and non-volatile memory

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What is the main purpose of the secondary fuel system?

a) To store fuel
b) To supply fuel to the combustion chamber
c) To monitor engine temperature

b) To supply fuel to the combustion chamber

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What is the difference between the primary and secondary fuel systems on an aircraft?

a) Primary stores fuel, secondary supplies it to the engine
b) Primary controls engine speed, secondary adjusts thrust
c) There is no difference between them

a) Primary stores fuel, secondary supplies it to the engine

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What are the two subsystems of the engine fuel system?

a) Combustion and distribution subsystems
b) Fuel distribution and fuel control subsystems
c) Storage and control subsystems

b) Fuel distribution and fuel control subsystems

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What is one main task of the engine fuel distribution system?

A) To safely supply fuel to the combustion chamber
B) To reduce fuel consumption
C) To store extra fuel

A) To safely supply fuel to the combustion chamber

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What is one main task of the engine fuel distribution system? A) To pressurize the fuel for vaporization B) To mix air with the fuel C) To reduce the engine’s temperature

A) To pressurize the fuel for vaporization

What is one main task of the engine fuel distribution system? A) To heat the fuel to prevent ice build-up B) To cool the fuel during high-speed operations C) To recycle unused fuel

A) To heat the fuel to prevent ice build-up

What is the first component in the fuel system after the low-pressure fuel shut-off valve? A) Low-pressure fuel pump B) Oil cooler C) Main fuel supply line

C) Main fuel supply line

What is the dual function of the oil cooler? A) To cool the oil and heat the fuel B) To heat the oil and filter the fuel C) To increase fuel pressure and cool the oil

A) To cool the oil and heat the fuel

What is the main purpose of the high-pressure fuel pump? A) To filter the fuel B) To increase fuel pressure for vaporization C) To measure fuel flow

B) To increase fuel pressure for vaporization

What is the main task of the fuel control unit? A) To meter and supply fuel to the nozzles B) To heat the fuel C) To measure fuel flow

A) To meter and supply fuel to the nozzles

What does the fuel flow transmitter measure? A) Fuel pressure in the oil cooler B) Fuel flow and usage C) Fuel temperature in the manifold

B) Fuel flow and usage

What is the approximate fuel pressure after the low-pressure fuel pump? A) 900 psi B) 175 psi C) 50 psi

B) 175 psi

What is the purpose of the overpressure relief valve in the high-pressure fuel pump? A) To increase fuel flow to the nozzles B) To prevent damage to the fuel system components C) To reduce fuel pressure to the oil cooler

B) To prevent damage to the fuel system components

What happens to the fuel that is not needed for combustion? A) It is stored in the oil cooler B) It returns to the fuel pump by the bypass return line C) It is ejected from the fuel system

B) It returns to the fuel pump by the bypass return line

What does the metering section of the fuel control unit do? A) It lets only the metered fuel pass to the nozzles B) It increases the fuel pressure to 175 psi C) It filters out impurities from the fuel

A) It lets only the metered fuel pass to the nozzles

What is the main task of engine-driven fuel pumps? A) To deliver a continuous supply of fuel at the correct pressure B) To cool the fuel for the nozzles C) To mix fuel with air for combustion

A) To deliver a continuous supply of fuel at the correct pressure

What are the two types of engine-driven fuel pumps? A) Variable and fixed displacement B) Constant and non-constant displacement C) High-pressure and low-pressure pumps

B) Constant and non-constant displacement

Which type of pump is typically used at the inlet of the engine-driven pump? A) Constant displacement pump B) Centrifugal pump (non-constant displacement) C) Gear pump

B) Centrifugal pump (non-constant displacement)

What is the function of a centrifugal pump in the fuel system? A) To vary the output as needed and boost flow to the second stage B) To pressurize the fuel for combustion C) To filter impurities from the fuel

A) To vary the output as needed and boost flow to the second stage

Why should a fuel pump never be turned without fuel flow supplied to the inlet? A) The pump requires fuel for lubrication B) The pump will overheat without fuel C) The pump will lose its calibration

A) The pump requires fuel for lubrication

Where is the low-pressure fuel filter located? A) Between the fuel control and the fuel nozzles B) Between the supply tanks and the engine fuel system C) Between the high-pressure pump and the bypass line

B) Between the supply tanks and the engine fuel system

What is the main purpose of the high-pressure fuel filter? A) To protect the fuel control from contaminants B) To increase fuel pressure to the required level C) To heat the fuel before combustion

A) To protect the fuel control from contaminants

What are the most common types of fuel filters? A) Micron filter, wafer screen filter, and plain screen mesh filter B) High-pressure filter, bypass filter, and centrifugal filter C) Oil filter, water filter, and air filter

A) Micron filter, wafer screen filter, and plain screen mesh filter

What does the low-pressure filter protect? A) The engine-driven fuel pumps B) The fuel control unit C) The fuel nozzles

A) The engine-driven fuel pumps

What does a micron filter remove? A) Large debris only B) Foreign matter measuring from 10-25 microns C) Water from the fuel

B) Foreign matter measuring from 10-25 microns

Why do micron filters need a pressure bypass valve? A) Because they heat the fuel B) Because they are prone to clogging C) Because they increase fuel pressure

B) Because they are prone to clogging

What materials are wafer screen filter elements made from? A) Porous cellulose B) Layers of bronze, brass, or steel screens C) Plastic mesh

B) Layers of bronze, brass, or steel screens

Which filters are most widely used for removing micronic particles? A) 200 mesh and 35 mesh micron filters B) Oil and water filters C) Ceramic and carbon filters

A) 200 mesh and 35 mesh micron filters

What is a micron? A) One-thousandth of a millimeter B) One-hundredth of a millimeter C) One-tenth of a millimeter

A) One-thousandth of a millimeter

Why are heat exchangers used in gas turbine engine fuel systems? A) To prevent ice formation in fuel filters B) To increase fuel pressure C) To clean the fuel

B) To prevent ice formation in fuel filters

What are the two sources of heat for heat exchangers in fuel systems? A) Engine bleed air and engine oil B) Fuel and water C) Battery power and sunlight

A) Engine bleed air and engine oil

What is an air-to-liquid heat exchanger? A) Uses engine oil as heat source B) Uses engine bleed air as heat source C) Uses fuel to heat oil

B) Uses engine bleed air as heat source

What does a liquid-to-liquid heat exchanger use to heat the fuel? A) Engine oil B) Engine coolant C) Bleed air

A) Engine oil

What does the fuel-cooled oil cooler do? A) Cools the oil and heats the fuel B) Filters the fuel before combustion C) Increases fuel pressure

A) Cools the oil and heats the fuel

What is the main function of fuel spray nozzles? A) To inject fuel in a highly atomised spray pattern B) To filter the fuel before combustion C) To pressurize the fuel

A) To inject fuel in a highly atomised spray pattern

Why is it important that fuel is evenly distributed in the combustion chamber? A) To prevent hot spots and liner burning B) To increase fuel pressure C) To reduce fuel flow

A) To prevent hot spots and liner burning

What is closely related to the design of fuel spray nozzles? A) The type of combustion chamber B) The type of fuel filter C) The oil cooling system

A) The type of combustion chamber

What does the fuel manifold do? A) Distributes fuel to individual fuel nozzles B) Filters the fuel before combustion C) Increases fuel pressure

A) Distributes fuel to individual fuel nozzles

Where is the fuel manifold usually located? A) Around the combustion case as a ring-shaped line B) Inside the fuel control unit C) At the fuel tank outlet

A) Around the combustion case as a ring-shaped line

What is the purpose of shrouds on fluid lines? A) To catch fluid leaks and carry them away to the engine drain mast B) To heat the fuel before combustion C) To increase fuel flow

A) To catch fluid leaks and carry them away to the engine drain mast

What are the two methods used to protect fluid line connections against leaks? A) Single sealed and double sealed connections B) Shrouded and double sealed connections C) Pressure valves and O-rings

B) Shrouded and double sealed connections

What can shrouded connections do? A) Prevent leaks completely B) Catch leaks and carry them away by the engine drain system C) Increase fuel pressure

B) Catch leaks and carry them away by the engine drain system

What prevents leakage from the coupling nut getting onto the hot combustion case in shrouded connections? A) A gasket B) An O-ring inside the shroud C) A metal clamp

B) An O-ring inside the shroud

What was used on older aircraft engines instead of one fuel supply line and one fuel manifold? A) A single fuel supply line and manifold B) Two fuel supply lines and two fuel manifolds C) Three fuel supply lines and one manifold

B) Two fuel supply lines and two fuel manifolds

What does the primary manifold supply? A) Secondary fuel nozzles B) Primary fuel nozzles C) Fuel control unit

B) Primary fuel nozzles

What does the secondary manifold supply? A) Primary fuel nozzles B) Secondary fuel nozzles C) Fuel pump

B) Secondary fuel nozzles

How is fuel sprayed into the combustion area? A) Through large vents B) Under pressure through small orifices C) By gravity flow

B) Under pressure through small orifices

What are the two types of fuel nozzles used? A) Single and dual B) Simplex and duplex C) Primary and secondary

B) Simplex and duplex

Which nozzle type usually requires a dual manifold and a pressurising valve or flow divider? A) Simplex nozzle B) Duplex nozzle C) Single manifold nozzle

B) Duplex nozzle

Which nozzle type requires only a single manifold for proper fuel delivery? A) Duplex nozzle B) Simplex nozzle C) Pressurised nozzle

B) Simplex nozzle

What are the two common methods of mounting fuel nozzles? A) External mounting and internal mounting B) Pressure mounting and flow mounting C) Dome mounting and elbow mounting

A) External mounting and internal mounting

Where is the nozzle located in external mounting? A) Inside the liner dome B) Near the dome, attached to the case or inlet air elbow C) Behind the fuel manifold

B) Near the dome, attached to the case or inlet air elbow

Why should fuel nozzles in an engine be matched? A) To increase fuel pressure B) To flow equal amounts of fuel for even distribution C) To reduce fuel flow

B) To flow equal amounts of fuel for even distribution

Where do fuel nozzles supply the metered fuel? A) To the rear of the combustion chamber B) To the forward part of the combustion chamber C) To the fuel manifold

B) To the forward part of the combustion chamber

What is a disadvantage of the simplex nozzle? A) It is too expensive B) It can only give good atomisation in a small fuel flow range C) It requires two manifolds

B) It can only give good atomisation in a small fuel flow range

How many sets of simplex nozzles are needed for good atomisation across a wide fuel flow range? A) One set B) Two sets C) Three sets

B) Two sets

What are the two sets of simplex nozzles called? A) Primary (small orifices) and secondary (large orifices) fuel nozzles B) Intake and exhaust nozzles C) Internal and external nozzles

A) Primary (small orifices) and secondary (large orifices) fuel nozzles

What type of nozzle do modern engines usually use instead of separate simplex nozzles? A) Duplex nozzle B) Single manifold nozzle C) Triple nozzle

A) Duplex nozzle

What is the function of the check valve in the fuel nozzle? A) To increase fuel pressure B) To close and prevent fuel entering the combustion chamber when fuel pressure decreases C) To mix air and fuel

B) To close and prevent fuel entering the combustion chamber when fuel pressure decreases

What must be done to access a nozzle mounted internally at the liner dome? A) Remove the chamber cover B) Remove the fuel manifold C) Detach the external mounting pad

A) Remove the chamber cover

15.11 Fuel Systems (Level 1, 4 Questions) Flashcards

(80 cards)