Aircraft Fuel Systems Flashcards
(114 cards)
1
Q
Fuel jettisoning is usually accomplished how?
A
through a common manifold and outlet in each wing.
2
Q
The primary purpose of an aircraft’s fuel jettison system is to quickly achieve a what?
A
lower landing weight.
3
Q
The fuel jettison valve must be designed to allow flight personnel to what?
A
to close the valve at any time and the fuel must discharge clear of the aircraft.
4
Q
Which of the following is employed to maintain lateral stability when jettisoning fuel?
A
Two separate independent systems.
5
Q
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?
A
14 CFR Parts 23 and 25 and CAM 4b
6
Q
Fuel is moved overboard in most fuel jettison systems by what?
A
boost pumps.
7
Q
Fuel jettisoning past the limits prescribed by Federal Aviation Regulations is usually prevented by what?
A
dump limit valves or a low-level circuit.
8
Q
Which procedure must be followed when defueling aircraft with sweptback wings?
A
Defuel the outboard wing tanks first.
9
Q
(Refer to Figure 17.) What is the purpose of the crossfeed valve?
A
Allow operation of engines from one tank.
10
Q
Normal fuel crossfeed system operation in multi-engine aircraft…
A
provides a means to maintain a balanced fuel load condition.
11
Q
How many vents, arranged so that they are not likely to become plugged at the same time, must be used in multiengine fuel systems?
A
Two
12
Q
What is the primary purpose of the crossfeed system?
A
It allows any tank to supply fuel to any engine.
13
Q
Fuel system components must be bonded and grounded in order to what?
A
drain off static charges.
14
Q
How many engine driven fuel pumps per engine are required for engines requiring fuel pumps?
A
One fuel pump for each engine.
15
Q
A typical large transport aircraft fuel manifold system allows how many of the following?
- All tanks can be serviced through a singe connection.
- Any engine can be fed from any tank.
- All engines can be fed from all tanks simultaneously.
- A damaged tank ca be isolated from the rest of the fuel system.
A
1, 2, 3, and 4
16
Q
A fuel system must be designed to prevent fuel-vapor ignition caused by what?
A
lightning.
17
Q
What is the minimum distance allowed between a fuel tank and the fire wall separating the engine?
A
One-half inch.
18
Q
Fuel baffles are installed in tanks to prevent ________ caused by changes in the attitude of the aircraft.
A
surging
19
Q
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.
A
flapper
20
Q
Fuel heaters are used with fuel systems for turbine engines to prevent _________ in the fuel from clogging system filters.
A
ice crystals
21
Q
A transducer in a fuel pressure system serves what function?
A
Converts fluid pressure directly through a transmitter to the indicator.
22
Q
The use of turbine fuels in aircraft has resulted in some problems not normally associated with aviation gasolines. One of these problems is what?
A
microbial contaminants.
23
Q
What is used in many aircraft to prevent bubbles in fuel after it leaves the tank when atmospheric pressure is lower than fuel vapor pressure?
A
Boost pumps.
24
Q
Which of the following precautions is most important during refueling operations?
A
Fuel to be used must be appropriately identified.
25
Before fueling an aircraft by using the pressure fueling method, what important precaution should be observed?
The truck pump pressure must be correct for that refueling system.
26
What flight safety-related advantage does a pressure fueling system provide?
Reduces the chances for fuel contamination.
27
Aircraft pressure fueling systems instructional procedure are normally placarded on the what?
fuel control panel access door.
28
Pressure fueling of aircraft is usually accomplished through what?
at least one single point connection.
29
Which of the following may be used for the repair of fuel leaks on most integral fuel tanks?
Riveting and resealing.
30
How is the outlet fuel pressure regulated on a submerged, single speed, centrifugal-type fuel pump?
By the pump's design and internal clearances.
31
What is one purpose of a fuel tank vent?
To maintain atmospheric pressure.
32
When inspecting a removable rigid fuel tank for leaks, what procedure should be followed?
pressurize the tank with air and brush with soapy water.
33
If it is necessary to enter an aircraft's fuel tank, which procedure should be avoided?
Conduct the defueling and tank purging operation in an air-conditioned building.
34
What is the recommended practice for cleaning a fuel tank before welding?
Steam clean the tank interior.
35
An aircraft's integral fuel tank is what?
a part of the aircraft structure.
36
Which gas is used for purging an aircraft fuel tank?
Carbon dioxide.
37
Why is the main fuel strainer located at the lowest point in the fuel system?
It traps any small amount of water that may be present in the fuel system?
38
The purpose of a diaphragm in a vane-type fuel pump is to what?
compensate fuel pressures to altitude changes.
39
When moving the mixture control on a normally operating engine into the idle cutoff position, engine RPM should what?
slightly increase before the engine starts to die.
40
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?
Anti-icing fuel additives and fuel heater.
41
As a general rule, which statement is true regarding fuel leaks?
Stains, seeps, and heavy seeps (in addition to running leaks), are considered flight hazards when located in unvented areas of the aircraft.
42
The presence of fuel stains around a fuel nozzle would indicate what?
clogged fuel nozzle.
43
What should be used to inert an integral fuel tank before attempting repairs?
CO 2 (carbon dioxide)
44
What should be used to remove flux from an aluminum tank after welded repairs?
Five percent solution of nitric or sulfuric acid.
45
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.
46
Why are jet fuels more susceptible to water contamination than aviation gasoline?
Jet fuel has a higher viscosity than gasoline.
47
When installing a rigid fuel line, 1/2 inch in diameter, at what intervals should the line be supported?
16 inches.
48
The probe of a capacitance-type fuel level gauge is essentially a what?
capacitor with fuel and air acting as a dielectric.
49
Which statement concerning an electronic capacitance-type fuel quantity indicating system is true?
It has no moving parts in the tank.
50
What type of remote-reading fuel quantity indicating system has several probes installed in each fuel tank?
Electronic
51
Which aircraft fuel quantity indicating system incorporates a signal amplifier?
Electronic.
52
A drip gauge may be used to measure what?
the amount of fuel in the tank.
53
The electronic-type fuel quantity indicating system consists of a bridge circuit, ...
an amplifier, an indicator, and a tank unit.
54
A probe or a series of probes is used in what kind of fuel quantity indicating system?
Capacitor
55
Why is the capacitance fluid quantity indicating system more accurate in measuring fuel level than a mechanical type?
It measures by weight instead of volume.
56
One advantage of electrical and electronic fuel quantity indicating systems is that...
several fuel tank levels can be read on one indicator.
57
A fuel totalizer is a component which indicates the what?
amount of fuel in all tanks.
58
A digital fuel totalizer automatically indicates the amount of fuel used, fuel remaining, current rate of consumption, and fuel...
weight aboard at takeoff.
59
What is the dielectric (nonconducting material) in a capacitance-type fuel quantity indicating system?
Fuel and air in the tank.
60
A capacitance-type fuel quantity indicating system measures fuel in what?
pounds.
61
What are the four general types of fuel quantity gauges?
Sight glass, mechanical, electrical, and electronic.
62
How does temperature affect fuel weight?
Cold fuel is heavier per gallon.
63
One advantage of electrical and electronic fuel quantity indicating systems is that the indicator what?
can be located any distance from the tank(s).
64
When fuel quantity is measured in pounds instead of gallons, the measurement will be more accurate because fuel volume...
varies with temperature change.
65
An electrical type fuel quantity indicating system consists of an indicator in the cockpit and a float...
in the tank that moves a connecting arm to the wiper on a variable resistor in the tank.
66
What is the purpose of a float-operated transmitter installed in a fuel tank?
It sends an electric signal to the fuel quantity indicator.
67
In an electronic-type fuel quantity indicating system, the tank sensing unit is a what?
capacitor.
68
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?
Zero.
69
What unit would be adjusted to change the fuel pressure warning limits?
Pressure-sensitive mechanism.
70
Select one means of controlling the fuel temperature on turbine-powered aircraft.
Engine bleed air to a heat exchanger.
71
What is the purpose of flapper-type check valves in integral fuel tanks?
To prevent fuel from flowing away from the boost pumps
72
What unit is generally used to actuate the fuel pressure warning system?
Pressure-sensitive mechanism.
73
What method is used on turbine-powered aircraft to determine when the condition of the fuel is approaching the danger of forming ice crystals?
Fuel temperature indicator.
74
Which of the following would give the first positive indication that a change-over from one fuel tank to another is needed?
Fuel pressure warning.
75
A fuel pressure warning switch contacts close and warning light is turned on when what?
The fuel pressure drops below specified limits.
76
A transmitter in a fuel pressure warning system serves what function?
Converts fluid pressure to an electrical signal.
77
Where is fuel pressure taken for the pressure warning signal on most aircraft engines?
Fuel pressure line of the carburetor.
78
Which of the following is necessary to effectively troubleshoot a fuel pressure warning system?
The manufacturer's maintenance manuals.
79
Which of the following would be most useful to locate and troubleshoot an internal fuel leak in an aircraft fuel system?
Maintenance manual diagrams and descriptions.
80
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...
a fuel pressure warning signal system.
81
The function of a fuel heater is to what?
Protect the engine fuel system from ice formation.
82
(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,
Both 1 and 2 are true.
83
(1) A fuel heater can use engine bleed air as source of heat.
(2) A fuel heater can use engine lubricating oil as a source of heat.
Regarding the above statements,
Both 1 and 2 are true.
84
(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,
Both 1 and 2 are true
85
A fuel pressure relief valve is required on an aircraft...
positive-displacement fuel pump.
86
The primary purpose of a fuel tank sump is to provide a what?
place for contaminants and water to settle, with a drain valve to remove the impurities.
87
Why are integral fuel tanks used in many large aircraft?
To reduce weight.
88
When an aircraft is fueled from a truck or fuel farm that has not been contaminated, daily draining...
of strainers and sumps is combined with periodic filter changes and inspection to ensure fuel is contaminant free.
89
When defueling an aircraft, which of the following must be accomplished?
Always defuel outside the hangar.
90
Integral fuel tanks on transport aircraft are what?
supported by the aircraft structure.
91
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?
The tank airspaces must be interconnected.
92
The purpose of the baffle plate in a fuel tank is to what?
resist fuel surging within the fuel tank.
93
What markings must be placed on or near each appropriate fuel filler cover on standard category aircraft?
The word "Avgas" and the minimum fuel grade.
94
What is one disadvantage of using aromatic aviation fuels?
Deteriorates rubber parts.
95
Fuel-boost pumps are operated...
to provide a positive flow of fuel to the engine.
96
Flapper valves are used in fuel tanks to what?
act as check valves.
97
Why are centrifugal-type boost pumps used in fuel systems of aircraft operating at high altitude?
To supply fuel under pressure to engine-driven pumps.
98
Why is it necessary to vent all aircraft fuel tanks?
To limit pressure differential between the tank and atmosphere.
99
According to Part 23, what minimum required markings must be placed at or near each appropriate fuel filler cover for reciprocating engine-powered airplanes?
The word "Avgas" and the minimum fuel grade.
100
The location of leaks and defects within the internal portions of the fuel system can usually be determined by what?
Observing the pressure gauge and operating the selector valves.
101
What type of fuel-booster pump requires a pressure relief valve?
Sliding vane.
102
To prevent vapor lock in fuel lines at high altitude, some aircraft are equipped with what?
booster pumps.
103
Some turbine-powered aircraft have a fuel temperature indicator located in the cockpit to what?
monitor the fuel temperature during high altitude flight.
104
When inspecting a fuel system, you should check all valves located downstream of boost pumps with the pumps...
operating.
105
The type of fuel-boost pump that separates air and vapor from the fuel before it enters the line to the carburetor is the what?
centrifugal-type pump.
106
On a large aircraft pressure refueling system, a pressure refueling receptacle and control panel will permit one person to what?
fuel or defuel any of the tanks on an aircraft.
107
When routing a fuel line between two rigidly mounted fittings the line should what?
have at least one bend between such fittings.
108
Which of the following tests can determine an aviation gasoline's tendency to vapor lock?
Reid vapor pressure test.
109
Microbial growth is produced by various forms of micro-organisms that live and multiply in water interfaces of jet fuels. Which of the following could result if microbial growth exists in a jet fuel tank and is not corrected?
Interference with fuel flow, interference with fuel quantity indicators, and electrolytic corrosive action in a metal tank.
110
The vapor pressure of aviation gasoline is what?
lower than the vapor pressure of automotive gasoline.
111
What can be done to eliminate or minimize the microbial growth problem in an aircraft jet fuel tank?
Use anti-icing and antibacterial additives.
112
What is the maximum vapor pressure allowable for an aircraft fuel?
7 psi.
113
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 what?
engine oil.
114
How may the antiknock characteristics of a fuel be improved?
By adding a knock inhibitor.
