Aircraft Fuel Systems Flashcards
Fuel jettisoning is usually accomplished how?
through a common manifold and outlet in each wing.
The primary purpose of an aircraft’s fuel jettison system is to quickly achieve a what?
lower landing weight.
The fuel jettison valve must be designed to allow flight personnel to what?
to close the valve at any time and the fuel must discharge clear of the aircraft.
Which of the following is employed to maintain lateral stability when jettisoning fuel?
Two separate independent systems.
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?
14 CFR Parts 23 and 25 and CAM 4b
Fuel is moved overboard in most fuel jettison systems by what?
boost pumps.
Fuel jettisoning past the limits prescribed by Federal Aviation Regulations is usually prevented by what?
dump limit valves or a low-level circuit.
Which procedure must be followed when defueling aircraft with sweptback wings?
Defuel the outboard wing tanks first.
(Refer to Figure 17.) What is the purpose of the crossfeed valve?
Allow operation of engines from one tank.
Normal fuel crossfeed system operation in multi-engine aircraft…
provides a means to maintain a balanced fuel load condition.
How many vents, arranged so that they are not likely to become plugged at the same time, must be used in multiengine fuel systems?
Two
What is the primary purpose of the crossfeed system?
It allows any tank to supply fuel to any engine.
Fuel system components must be bonded and grounded in order to what?
drain off static charges.
How many engine driven fuel pumps per engine are required for engines requiring fuel pumps?
One fuel pump for each engine.
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.
1, 2, 3, and 4
A fuel system must be designed to prevent fuel-vapor ignition caused by what?
lightning.
What is the minimum distance allowed between a fuel tank and the fire wall separating the engine?
One-half inch.
Fuel baffles are installed in tanks to prevent ________ caused by changes in the attitude of the aircraft.
surging
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.
flapper
Fuel heaters are used with fuel systems for turbine engines to prevent _________ in the fuel from clogging system filters.
ice crystals
A transducer in a fuel pressure system serves what function?
Converts fluid pressure directly through a transmitter to the indicator.
The use of turbine fuels in aircraft has resulted in some problems not normally associated with aviation gasolines. One of these problems is what?
microbial contaminants.
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?
Boost pumps.
Which of the following precautions is most important during refueling operations?
Fuel to be used must be appropriately identified.
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.
What flight safety-related advantage does a pressure fueling system provide?
Reduces the chances for fuel contamination.
Aircraft pressure fueling systems instructional procedure are normally placarded on the what?
fuel control panel access door.
Pressure fueling of aircraft is usually accomplished through what?
at least one single point connection.
Which of the following may be used for the repair of fuel leaks on most integral fuel tanks?
Riveting and resealing.
How is the outlet fuel pressure regulated on a submerged, single speed, centrifugal-type fuel pump?
By the pump’s design and internal clearances.
What is one purpose of a fuel tank vent?
To maintain atmospheric pressure.
When inspecting a removable rigid fuel tank for leaks, what procedure should be followed?
pressurize the tank with air and brush with soapy water.
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.
What is the recommended practice for cleaning a fuel tank before welding?
Steam clean the tank interior.
An aircraft’s integral fuel tank is what?
a part of the aircraft structure.
Which gas is used for purging an aircraft fuel tank?
Carbon dioxide.
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?
The purpose of a diaphragm in a vane-type fuel pump is to what?
compensate fuel pressures to altitude changes.
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.
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.
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.
The presence of fuel stains around a fuel nozzle would indicate what?
clogged fuel nozzle.
What should be used to inert an integral fuel tank before attempting repairs?
CO 2 (carbon dioxide)
What should be used to remove flux from an aluminum tank after welded repairs?
Five percent solution of nitric or sulfuric acid.
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.