Aircraft Fuel Systems

Question 1

What must each fuel quantity indicator be calibrated to read during level flight when the quantity of fuel remaining is equal to the unusable fuel supply?

Answer 1

Zero

Question 2

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

Answer 2

Place for contaminants and water to settle, with a drain valve to remove the umpurities.

Question 3

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

Answer 3

Observing the pressure gauge and operating the selector valves.

Question 4

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

Answer 4

Fuel and air in the tank.

Question 5

Fuel system components must be bonded and grounded in order to

Answer 5

Drain off static charges.

Question 6

The probe of a capacitance-type fuel gauge is essentially a

Answer 6

Capacitor with fuel and air acting as a dielectric.

Question 7

1) A fuel heater can use engine bleed air as a source of heat.
2) A fuel heater can use engine lubricating oil as a source of heat.
Regarding the above statements,

Answer 7

Both no.1 and no.2 are true

Question 8

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

Answer 8

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

Question 9

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?

Answer 9

The tank airspaces must be interconnected.

Question 10

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

Answer 10

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

Question 11

Fuel is moved overboard in most fuel jettison systems by

Answer 11

Boost pumps

Question 12

What markings must be placed on or near each appropriate fuel filler cover on standard category aircraft?

Answer 12

The word ‘AVgas’ and the minimum fuel grade.

Question 13

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

Answer 13

It ha no moving parts in the tank.

Question 14

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

Answer 14

Pressure-sensitive mechanism

Question 15

The type of fuel-boost pump that separates air and vapor from the fuel before it enter the line to the carburetor is the

Answer 15

Centrifugal-type pump

Question 16

When installing a rigid fuel line, 1/2 inch diameter, at what intervals should the line be supported?

Answer 16

16 inches

Question 17

Which of the following is necessary to effectively troubleshoot a fuel pressure warning system?

Answer 17

The manufacturer’s maintenance manual

Question 18

The presence of fuel stains around a fuel nozzle would indicate

Answer 18

Clogged fuel nozzle

Question 19

The vapor pressure of aviation gasoline is

Answer 19

Lower than the vapor pressure of automotive gasoline.

Question 20

1) The fuel jettison must be designed to allow flight personnel to close the valve during any part of the jettisoning operation.
2) During the fuel jettisoning operation, the fuel must discharge clear of any part of the airplane.
Regarding the above statements,

Answer 20

Both no.1 and no.2 are true.

Question 21

1) On a large aircraft pressure refueling system, a pressure refueling receptacle and control panel will permit one person to fuel or defuel any or all fuel tanks of an aircraft.
2) Because of the fuel tank area, there are some advantages to a pressure fueling system in light aircraft.
Regarding the above statements,

Answer 21

Only no.1 is true.

Question 22

Why are integral fuel tanks are used in many large aircraft?

Answer 22

To reduce weight.

Question 23

How is the outlet fuel pressure regulated on a submerged, single-speed, centrifugal-type fuel pump?

Answer 23

By the pump’s design and internal clearances.

Question 24

A fuel jettison system is required under certain conditions if the maximum takeoff weight exceeds the maximum landing weight. What regulations cover the requirements of fuel jettisoning?

Answer 24

Federal Aviation Regulation part 23,35, and CAM 4b

Question 25

Fuel heaters are used with fuel systems for turbine engines to prevent ____ in the fuel from clogging system filters.

Answer 25

Ice crystals.

Question 26

Some turbine powered aircraft have a fuel temperature indictor located in the cockpit to

Answer 26

Monitor the fuel temperature during high altitude flight.

Question 27

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

Answer 27

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

Question 28

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

Answer 28

Riveting and resealing.

Question 29

A fuel pressure warning switch controls close and warning light is turned on when

Answer 29

The fuel pressure drops below specified limits.

Question 30

What flight safety-related advantage does a pressure fueling system provide?

Answer 30

Reduces the chances for fuel contamination.

Question 31

Select one means of controlling the fuel temperature on turbine-powered aircraft.

Answer 31

Engine bleed air to a heat exchanger.

Question 32

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?

Answer 32

Anti-icing fuel additives and fuel heater.

Question 33

What should be used to inert an integral fuel tank before attempting repairs?

Answer 33

CO2

Question 34

Why is the main fuel strainer located at the lowest point in the fuel system?

Answer 34

it traps any small amount of water that may be present in the fuel system.

Question 35

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

Answer 35

An amplifier, an indicator, and a tank unit.

Question 36

What are the four general types of fuel quantity gauges? 1) ) Sight glass 2) Mechanical 3) Electrical 4) Electronic 5) Bourdon tube 6) Vane-type transmitter 7) Litmus indicator 8) Direct-reading static pressure type.

Answer 36

1,2,3,4

Question 37

If it is necessary to enter an aircraft's fuel tank, which procedure should be avoided?

Answer 37

Conduct the defueling and tank purging operation in an air-conditioned building.

Question 38

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

Answer 38

Pressurize the tank with air and brush with soapy water.

Question 39

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

Answer 39

A fuel pressure warning signal system.

Question 40

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

Answer 40

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

Question 41

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

Answer 41

Varies with temperature change.

Question 42

A typical large transport aircraft fuel manifold systems allows how many of the following? 1) All tanks can be serviced through a single connection. 2) Any engine can be fed from any tank. 3) All engines can be fed from all tanks simultaneously. 4) A damaged tank can be isolated from the rest of the fuel system.

Answer 42

1,2,3, and 4

Question 43

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

Answer 43

Two separate independent systems.

Question 44

1) If aviation gasoline vaporizes too readily, fuel lines may become filled with vapor and cause increased fuel flow. 2) A measure of gasoline's tendency to vapor lock is obtained from the Reid vapor pressure test. Regarding the above statements,

Answer 44

Only no.2 is true

Question 45

How many vents, arranged so that they are not likely to become plugged at the same time, must be used in multi-engine fuel systems?

Answer 45

Two

Question 46

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

Answer 46

Compensate fuel pressures to altitude charges.

Question 47

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

Answer 47

It sends an electrical signal to the fuel quantity indicator.

Question 48

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

Answer 48

Fuel pressure line of the carburetor.

Question 49

Flapper valves are used in fuel tanks to

Answer 49

act as check valves

Question 50

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

Answer 50

To prevent fuel from flowing away from the boost pumps.

Question 51

What is the primary purpose of the crossfeed system?

Answer 51

It allows any tank to supply fuel to any engine.

Question 52

A transducer in a fuel pressure system serves what function?

Answer 52

Converts fluid pressure directly through a transmitter to the indicator.

Question 53

What is one purpose of a fuel tank vent?

Answer 53

To maintain atmospheric pressure.

Question 54

Why is it necessary to vent all aircraft fuel tanks?

Answer 54

To limit pressure differential between the tank and atmosphere.

Question 55

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

Answer 55

Capacitor

Question 56

What type of remote-reading fuel quantity indicating system has several probes installed in each fuel tank?

Answer 56

Electronic

Question 57

In an electronic-type fuel quantity indicating system, the tank sensing unit is a

Answer 57

Capacitor

Question 58

Pressure fueling of aircraft is usually accomplished through

Answer 58

At least one single point connection.

Question 59

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

Answer 59

Sliding vane

Question 60

Why are jet fuels more susceptible to water contamination than aviation gasoline?

Answer 60

Jet fuel has a higher viscosity than gasoline.

Question 61

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

Answer 61

Dump limit valves or a low-level circuit.

Question 62

Why is the capacitance fluid quantity indicating system more accurate in measuring fuel level than a mechanical type?

Answer 62

It measures by weight instead of volume.

Question 63

A drip gauge may be used to measure

Answer 63

The amount of fuel in the tank.

Question 64

Fuel boost pumps are operated

Answer 64

To provide a positive flow of fuel to the engine.

Question 65

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

Answer 65

To supply fuel under pressure to engine-driven pumps.

Question 66

Which of the following precautions is most important during refueling operations?

Answer 66

Fuel to be used must be appropriately identified.

Question 67

Aircraft pressure fueling systems instructional procedures are normally placarded on the

Answer 67

Fuel control panel access door.

Question 68

Many fuel tanks incorporate ___ valves to prevent fuel from flowing away from the boost pump or tank outlet when the aircraft is in a high 'G' maneuver.

Answer 68

Flapper

Question 69

How may the antiknock characteristics of a fuel be improved?

Answer 69

By adding a knock inhibitor.

Question 70

The purpose of the baffle plate in a fuel tank is to

Answer 70

Resist fuel surging within the fuel tank.

Question 71

What is the recommended practice for cleaning a fuel tank before welding?

Answer 71

Steam clean the tank interior.

Question 72

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

Answer 72

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

Question 73

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

Answer 73

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

Question 74

The primary purpose of an aircraft's fuel jettison system is to quickly achieve a

Answer 74

Lower landing weight

Question 75

When moving the mixture control on a normally operating engine into the idle cut off position, engine RPM should

Answer 75

Slightly increase before the engine starts to die.

Question 76

If a bladder-type fuel tank is to be left empty for an extended period of time, the inside of the tank should be coated with a film of

Answer 76

Engine oil

Question 77

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

Answer 77

5 percent solution of nitric or sulfuric acid.

Question 78

Which of the following would be most useful t locate and troubleshoot an internal fuel leak in an aircraft system?

Answer 78

Maintenance manual diagrams and descriptions.

Question 79

When inspecting a fuel system, you should check all valves located downstream of boost pumps with the pumps

Answer 79

Operating

Question 80

The use of turbine fuels in aircraft has resulted in some problems not normally associated with aviation gasolines. One of these problems is

Answer 80

Microbial contaminants.

Question 81

1) A fuel pressure gauge is a differential pressure indicator. 2) A fuel pressure gauge indicates the pressure of the fuel entering the carburetor. Regarding the above statements

Answer 81

Both no.1 and no.2 are true

Question 82

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

Answer 82

Converts fluid pressure to an electrical signal.

Question 83

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

Answer 83

Fuel temperature indicator.

Question 84

Integral fuel tanks on transport aircraft are

Answer 84

Supported by the aircraft structure.

Question 85

Fuel jettisoning is usually accomplished

Answer 85

Through a common manifold and outlet in each wing.

Question 86

one advantage of electrical and electronic fuel quantity indicating systems is that

Answer 86

Several fuel tank levels can be read on one indicator.

Question 87

How does temperature affect fuel weight?

Answer 87

Cold fuel is heavier per gallon.

Question 88

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

Answer 88

Weight, aboard at takeoff.

Question 89

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

Answer 89

One fuel pump for each engine.

Question 90

1) The function of a fuel heater is to protect the engine fuel system from ice formation. 2) An aircraft fuel heater cannot be used to thaw ice in the fuel screen. Regarding the above statements,

Answer 90

Only no.1 is true.

Question 91

A capacitance-type fuel quantity indicating system measures fuel in

Answer 91

Pounds

Question 92

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

Answer 92

Fuel pressure warning

Question 93

1) A fuel pressure relief valve is required on an aircraft positive-displacement fuel pump 2) A fuel pressure relief valve is required on an aircraft centrifugal boost pump. Regarding the above statements,

Answer 93

Only no.1 is true

Question 94

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

Answer 94

Pressure-sensitive mechanism

Question 95

What can be done to eliminate or minimize the microbial growth problem in an aircraft jet fuel tank?

Answer 95

Use anti-icing and antibacterial additives.

Question 96

To prevent vapor lock in fuel lines at high altitude, some aircraft are equipped with

Answer 96

Booster pumps

Question 97

What is the maximum vapor pressure allowable for an aircraft fuel?

Answer 97

7 PSI

Question 98

What is one disadvantage of using aromatic aviation fuels?

Answer 98

Deteriorates rubber parts.

Question 99

What is used in many aircraft to prevent bubbles in the fuel after it leaves the tank when atmospheric pressure is lower than fuel vapor pressure?

Answer 99

Boost pumps

Question 100

Which aircraft fuel quantity indicating system incorporates a signal amplifier?

Answer 100

Electronic

Question 101

An aircraft's integral fuel tank is

Answer 101

A part of the aircraft structure.

Question 102

Normal fuel crossfeed system operation in multiengine aircraft

Answer 102

Provides a means to maintain a balanced fuel load condition.

Question 103

Which procedure must be followed when defueling aircraft with swept back wings?

Answer 103

Defuel the outboard wing tanks first.

Question 104

A fuel totalizer is a component which indicates the

Answer 104

Amount of fuel in all tanks.

Question 105

Fuel baffles are installed in tanks to prevent ___ caused by changes in the altitude of the aircraft.

Answer 105

Surging.

Question 106

(Refer to Figure 17.) What is the purpose of the pump crossfeed valve?

Answer 106

Allow operation of engines from one tank.

Question 107

1) Gas-turbine-engine fuel systems are very susceptible to the formation of ice in the fuel filters. 2) A fuel heater operates as a heat exchanger to warm the fuel. Regarding the above statements,

Answer 107

Both no.1 and no.2 are true.

Question 108

When defueling an aircraft, which of the following must be accomplished?

Answer 108

Always defuel outside the hangar.

Question 109

Microbial growth is produced by various forms of microorganisms 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 and is not corrected? 1) Interference with fuel flow. 2) interference with fuel quantity indicators. 3) Engine seizure. 4) Electrolytic corrosive action in a metal tank. 5) Lower grade rating of the fuel. 6) Electrolytic corrosive action ina rubber tank?

Answer 109

1,2,4

Question 110

Which gas is used for purging an aircraft fuel tank?

Answer 110

Carbon dioxide

Question 111

According to part 23, what minimum required markings must be placed at or near each appropriate fuel filler cover for reciprocating engine-powered airplanes?

Answer 111

The word 'Avgas' and the minimum fuel grade.

Question 112

A fuel system must be designed to prevent fuel-vapor ignition caused by

Answer 112

Lightning

Question 113

When routing a fuel line between two rigidly mounted fittings the line should

Answer 113

Have at least one bend between such fittings.

Question 114

What is the minimum distance allowed between a fuel tank and the fire wall separately from the engine?

Answer 114

One-half inch.