Airframe-Aircraft Fuel Systems

The purpose of a diaphragm in a vane-type fuel pump is to

ANSWERS

equalize fuel pressure at all speeds.

*

vary fuel pressure according to throttle setting

*

compensate fuel pressures to altitude changes.

compensate fuel pressures to altitude changes.

When an aircraft is fueled from a truck or fuel farm that has not been contaminated, daily draining

ANSWERS

is not required because fuel trucks and fuel farms may make use of laser contaminant identification technology.

*

of strainers and sumps is combined with periodic filter changes and inspection to ensure fuel is contaminant free.

*

is only required if the fuel truck or farm has not been in continuous service.

of strainers and sumps is combined with periodic filter changes and inspection to ensure fuel is contaminant free.

The primary purpose of a fuel tank sump is to provide a

ANSWERS

way to shut off fuel flow or to route the fuel to a desired location.

*

place for contaminants and water to settle, with a drain valve to remove the impurities.

*

way to manually operate valves on a fuel tank to isolate or direct fuel to a pump.

place for contaminants and water to settle, with a drain valve to remove the impurities.

The function of a fuel heater is to

ANSWERS

protect the engine fuel system from ice formation,

*

protect the fuel from freezing.

*

heat the fuel to combustion temperature.

protect the engine fuel system from ice formation,

Normal fuel crossfeed system operation in multiengine aircraft

ANSWERS

calls for jettisoning of fuel overboard to correct lateral instability.

*

reduces contamination and/or fire hazards during fueling or defueling operations.

*

provides a means to maintain a balanced fuel load condition.

provides a means to maintain a balanced fuel load condition.

A fuel pressure relief valve is required on an aircraft

ANSWERS

positive-displacement fuel pump.

*

centrifugal boost fuel pump.

*

positive-displacement fuel pump and centrifugal boost fuel pump.

positive-displacement fuel pump.

Which procedure must be followed when defueling aircraft with sweptback wings?

ANSWERS

Defuel all the tanks at one time.

Defuel the inboard wing tanks first.

Defuel the outboard wing tanks first.

Defuel the outboard wing tanks first

A transmitter in a fuel pressure warning system serves what function?

ANSWERS

Transmits an electrical signal to fluid pressure.

*

Converts fluid pressure to an electrical signal.

*

Transmits fluid pressure directly to the indicator.

Converts fluid pressure to an electrical signal.

What method is used on turbine-powered aircraft to determine when the condition of the fuel is approaching the danger of forming ice crystals?

ANSWERS

Fuel pressure warning.

Fuel pressure gauge.

Fuel temperature indicator.

Fuel temperature indicator.

What precautions must be observed if a gravity-feed fuel system is permitted to supply

ANSWERS

fuel to an engine from more than one tank at a time?

* The tank airspaces must be interconnected.

*

The fuel outlet ports of each tank must have the same cross-sectional area.

*

Each tank must have a valve in its outlet that automatically shuts off the line when the tank is empty.

The tank airspaces must be interconnected.

What should be used to remove flux from an aluminum tank after welded repairs?

ANSWERS

Soft brush and warm water.

*

Five percent solution of nitric or sulfuric acid.

*

Mild solution of soap and warm water.

Five percent solution of nitric or sulfuric acid.

A transmitter in a fuel pressure warning system serves what function?

ANSWERS

Transmits an electrical signal to fluid pressure.

*

Converts fluid pressure to an electrical signal.

*

Transmits fluid pressure directly to the indicator.

Converts fluid pressure to an electrical signal.

Which statement concerning an electronic capacitance-type fuel quantity indicating system is true?

ANSWERS

It has no moving parts in the tank.

*

It has two tubes separated by an electronic field in the tank.

*

It utilizes a variable capacitor to indicate the fuel tank capacity.

It has no moving parts in the tank.

In some aircraft with several fuel tanks, the possible danger of allowing the fuel supply in one tank to become exhausted before the selector valve is switched to another tank is prevented by the installation of

ANSWERS

a fuel pressure warning signal system.

*

a fuel pressure relief valve.

*

an engine fuel pump bypass valve.

a fuel pressure warning signal system.

A digital fuel totalizer automatically indicates the amount of fuel used, fuel remaining, current rate of consumption, and fuel

ANSWERS

weight aboard at takeoff.

*

remaining at the 45-minute IFR fuel reserve.

*

remaining, flight time at the current power setting.

weight aboard at takeoff.

The electronic-type fuel quantity indicating system consists of a bridge circuit,

ANSWERS

an amplifier, an indicator, and a tank unit.

*

a tank, an amplifier, and an indicator.

*

tank unit, a tank, and an amplifier.

an amplifier, an indicator, and a tank unit.

What unit is generally used to actuate the fuel pressure warning system?

ANSWERS

Fuel flowmeter.

*

Pressure-sensitive mechanism.

*

Fuel pressure gauge.

Pressure-sensitive mechanism.

A typical large transport aircraft fuel manifold system allows which of the following?

ANSWERS

Tanks must be serviced through multiple connections.

*

Engines can be fed only from a specified tank

*

A damaged tank can be isolated from the rest of the fuel system.

A damaged tank can be isolated from the rest of the fuel system.

What unit would be adjusted to change the fuel pressure warning limits?

ANSWERS

Fuel flowmeter bypass valve.

*

Pressure-sensitive mechanism.

*

Fuel pressure relief valve.

Pressure-sensitive mechanism.

Where is fuel pressure taken for the pressure warning signal on most aircraft engines?

ANSWERS

Outlet side of the boost pump.

*

Fuel pressure line of the carburetor.

*

Between the fuel pump and the strainer.

Fuel pressure line of the carburetor.

Microbial growth is produced by various forms of micro-organisms that live and multiply in the water interfaces of jet fuels. Which of the following could result if microbial growth exists in a jet fuel tank?

ANSWERS

Interference with fuel flow, interference with fuel quantity indicators, and electrolytic corrosive action in a metal tank.

*

Interference with fuel quantity indicators, engine seizure, or a lower grade rating of the fuel.

*

Interference with fuel flow, lower grade rating of the fuel, or electrolytic corrosive action in a rubber tank.

Interference with fuel flow, interference with fuel quantity indicators, and electrolytic corrosive action in a metal tank.

An electrical type fuel quantity indicating system consists of an indicator in the flight deck and a float

ANSWERS

in the tank that moves a connecting arm to the wiper on a variable resistor in the tank.

*

attached to a rod that moves up or down in a calibrated cylinder.

*

in the tank that operates with alternating current and uses constant resistance in a circuit to drive a ratiometer-type indicator.

in the tank that moves a connecting arm to the wiper on a variable resistor in the tank.

Which of the following statements is true?

ANSWERS

fuel heater cannot use engine bleed air as a source of heat.

*

A fuel heater can use engine lubricating oil as a source of heat.

*

A fuel heater cannot use engine lubricating oil as a source of heat.

A fuel heater can use engine lubricating oil as a source of heat.

Which of the following would give the first positive indication that a change-over from one fuel tank to another is needed?

ANSWERS

Fuel pressure warning.

Fuel pressure gauge.

Fuel quantity indicator.

Fuel pressure warning.

Why is it necessary to vent all aircraft fuel tanks?

ANSWERS

To ensure a positive head pressure for a submerged boost pump.

*

To exhaust fuel vapors.

*

To limit pressure differential between the tank and atmosphere.

To limit pressure differential between the tank and atmosphere.

Which of the following statements is true?

ANSWERS

Gas-turbine-engine fuel systems are not susceptible to the formation of ice in the fuel filters.

*

A fuel heater operates as a heat disperser to cool the fuel.

*

Gas-turbine-engine fuel systems are very susceptible to the formation of ice on the fuel filters.

Gas-turbine-engine fuel systems are very susceptible to the formation of ice on the fuel filters.

The location of leaks and defects within the internal portions of the fuel system can usually be determined by

ANSWERS

visual inspection for evidence of wet spots and stains, and feeling for unusually warm components.

*

performing a fuel flow check.

*

observing the pressure gauge and operating the selector valves.

observing the pressure gauge and operating the selector valves.

What is the dielectric (nonconducting material) in a capacitance-type fuel quantity indicating system?

ANSWERS

Outer shell of the capacitor.

Fuel in the tank.

Fuel and air in the tank.

Fuel and air in the tank.

What is the purpose of flapper-type check valves in integral fuel tanks?

ANSWERS

To allow defueling of the tanks by suction.

*

To prevent fuel from flowing away from the boost pumps.

*

To allow the engine-driven pumps to draw fuel directly from the tank if the boost pump fails.

To prevent fuel from flowing away from the boost pumps.

Fuel jettisoning past the limits prescribed by Federal Aviation Regulations is usually prevented by

ANSWERS

closely monitoring the fuel quantity and turning off the fuel dump switch(es).

*

dump limit valves or a low-level circuit.

*

standpipes in the fuel tanks.

dump limit valves or a low-level circuit.

What precautions must be observed if a gravity-feed fuel system is permitted to supply fuel to an engine from more than one tank at a time?

ANSWERS

The tank airspaces must be interconnected.

*

The fuel outlet ports of each tank must have the same cross-sectional area.

*

Each tank must have a valve in its outlet that automatically shuts off the line when the tank is empty.

The tank airspaces must be interconnected.

Fuel-boost pumps are operated

ANSWERS

to provide a positive flow of fuel to the engine.

*

primarily for fuel transfer.

*

automatically from fuel pressure.

to provide a positive flow of fuel to the engine.

What type of fuel-booster pump requires a pressure relief valve?

ANSWERS

Concentric.

Sliding vane.

Centrifugal.

Sliding vane.

When inspecting a removable rigid fuel tank for leaks, what procedure should be followed?

ANSWERS

pressurize the tank with air and brush with soapy water.

*

fill the tank with water and pressurize with air and brush with soapy water.

*

pressurize the tank with air and submerge in water to locate leaks.

pressurize the tank with air and brush with soapy water.

A capacitance-type fuel quantity indicating system measures fuel in

ANSWERS

pounds.

pounds per hour.

gallons.

pounds

Aircraft pressure fueling systems instructional procedures are normally placarded on the

ANSWERS

fuel control panel access door.

*

lower wing surface adjacent to the access door.

*

aircraft ground connection point.

fuel control panel access door.

Which of the following may be used for the repair of fuel leaks on most integral fuel tanks?

ANSWERS

Welding and resealing.

*

Brazing and resealing.

*

Riveting and resealing.

Riveting and resealing

One advantage of electrical and electronic fuel quantity indicating systems is that the indicator

ANSWERS

can be located any distance from the tank(s).

*

has no movable devices.

*

always measures volume instead of mass.

can be located any distance from the tank(s).

Before fueling an aircraft by using the pressure fueling method, what important precaution should be observed?

ANSWERS

The truck pump pressure must be correct for that refueling system.

*

The truck pump pressure must be adjusted for minimum filter pressure.

*

The aircraft's electrical system must be on to indicate quantity gauge readings.

The truck pump pressure must be correct for that refueling system.

When fuel quantity is measured in pounds instead of gallons, the measurement will be more accurate because fuel volume

ANSWERS

varies with temperature change.

*

increases when temperature decreases.

*

varies with changes in atmospheric pressure.

varies with temperature change.

Which of the following statements is true?

ANSWERS

fuel pressure gauge is not a differential pressure indicator.

*

fuel pressure gauge indicates the pressure of the fuel entering the carburetor.

*

A fuel pressure gauge indicates the pressure of the fuel entering the combustion chamber.

fuel pressure gauge indicates the pressure of the fuel entering the carburetor.

Why are centrifugal-type boost pumps used in fuel systems of aircraft operating at high altitude?

ANSWERS

Because they are positive displacement pumps.

*

To supply fuel under pressure to engine driven pumps.

*

To permit cooling air to circulate around the motor.

To supply fuel under pressure to engine driven pumps.

Which of the following is employed to maintain lateral stability when jettisoning fuel?

ANSWERS

Two separate independent systems.

*

Crossfeed system.

*

Two interconnected systems.

Two separate independent systems.

A fuel totalizer is a component which indicates the

ANSWERS

total amount of fuel being consumed by all engines.

*

amount of fuel in any given tank.

*

amount of fuel in all tanks.

amount of fuel in all tanks.

Fuel-boost pumps are operated

ANSWERS

to provide a positive flow of fuel to the engine.

*

primarily for fuel transfer.

*

automatically from fuel pressure.

to provide a positive flow of fuel to the engine.

As a general rule, which statement is true regarding fuel leaks?

ANSWERS

Stains, seeps, and heavy seeps are not flight hazards.

*

All fuel leaks regardless of location or severity are considered a hazard to flight.

*

Stains, seeps, and heavy seeps (in addition to running leaks), are considered flight hazards when located in unvented areas of the aircraft.

Stains, seeps, and heavy seeps (in addition to running leaks), are considered flight hazards when located in unvented areas of the aircraft.

Some turbine powered aircraft have a fuel temperature indicator located in the flight deck

ANSWERS

monitor the fuel flow in the event that ice crystals form in the fuel system.

*

monitor the fuel temperature during high altitude flight.

*

ascertain the amount of fuel onboard the aircraft when ice starts to form in the fuel tanks.

monitor the fuel temperature during high altitude flight.

What is the purpose of a float-operated transmitter installed in a fuel tank?

ANSWERS

It sends an electric signal to the fuel quantity indicator.

*

It senses the total amount of fuel density.

*

It senses the dielectric qualities of fuel and air in the tank.

It sends an electric signal to the fuel quantity indicator.

How many engine driven fuel pumps per engine are required for engines requiring fuel pumps?

ANSWERS

Two engines can share one fuel pump.

One fuel pump for each engine.

Two fuel pumps for each engine.

One fuel pump for each engine.

A probe or a series of probes is used in what kind of fuel quantity indicating system?

*Selsyn.

*Capacitor.

*Synchro.

Capacitor.

What is the minimum distance allowed between an fuel tank and the fire wall separating the engine?

*One-half inch

*One inch.

*Two inches.

One-half inch

Fuel jettisoning is usually accomplished

*through a common manifold and outlet in each wing.

*by gravity flow into the outboard wing tanks and overboard through a common outlet in each wing.

*through individual outlets for each tank.

through a common manifold and outlet in each wing.

What method would be used to check for internal leakage of a fuel valve without removing the valve from the aircraft?

*Place the valve in the OFF position, drain the strainer bowl, and with boost pump on, watch to see if fuel flows to the strainer bowl.

*Remove fuel cap(s), turn boost pump (s) on, and watch for bubbling in the tanks.

*Apply regulated air pressure on the downstream side of the fuel pump and listen for air passing through the valve.

Place the valve in the OFF position, drain the strainer bowl, and with boost pump on, watch to see if fuel flows to the strainer bowl.

A fuel pressure relief valve is required on an aircraft

*positive-displacement fuel pump.

*centrifugal boost fuel pump.

*positive-displacement fuel pump and centrifugal boost fuel pump.

positive-displacement fuel pump.

What is a key characteristic of approved sustainable aviation fuel (SAF) when blended with conventional Jet A or Jet A1 fuel?

*It must be used only in specially modified turbine engines.

*It is a drop-in fuel that meets existing ASTM specifications when properly blended.

*It has a significantly higher energy content than conventional jet fuel.

It is a drop-in fuel that meets existing ASTM specifications when properly blended.

Fuel jettisoning prevented by past the limits prescribed by Federal Aviation Regulations is usually

*closely monitoring the fuel quantity and turning off the fuel dump switch(es).

*dump limit valves or a low-level circuit.

*standpipes in the fuel tanks.

dump limit valves or a low-level circuit.