Aircraft Fuel Systems Oral Flashcards
What is used as the sensor in the fuel tank for an electronic-type fuel quantity indicating system?
Tubular capacitors that extend across the fuel tank from top to bottom.
What is the principle upon which the electronic-type fuel quantity indicating system operates?
Tubular capacitors that extend across the fuel tanks change their capacitance as their fuel level changes. The dielectric constant (k) of the fuel is approximately twice that of air.
What is used as a sensor in the fuel tank for the older resistance-type fuel quantity indicating system?
A variable resistor with an arm that is moved by a float riding on top of the fuel in the tank.
What are two types of fuel cells used in modern aircraft?
Integrated fuel cells (cells that are sealed off portion to the structure). And bladder type cells.
Why are fuel tanks divided into compartments or have baffles installed in them?
The compartments or baffles keep the fuel from surging back and forth as the aircraft changes its attitude in flight.
What is the purpose of a drip gage in the fuel tank of a large aircraft?
The drip gage allows a mechanic to check the fuel level in a tank from the bottom of the tank.
What markings must appear near the filler opening of the fuel tanks on reciprocating-engine-powered aircraft, and on a turbine-powered aircraft?
On a reciprocating engine powered aircraft: the words “AVGAS” and the minimum grade of fuel.
On a turbine engine powered aircraft: the words “Jet Fuel”, the permissible fuel designations, the maximum permissible fueling supply pressure and the maximum permissible defueling pressure.
Where can you find the correct part number for the fuel quantity sensor to be installed in an aircraft fuel tank?
In the IPC of the aircraft.
When must the fuel quantity indicating system indicate zero?
During level flight when the fuel in the tank is equal to the unusable fuel supply.
Where are fuel system strainers located?
One strainer is located in the outlet of the tank, and the main strainer is located in the fuel line between the outlet of the fuel tank and the inlet to the fuel metering device.
Why do the fuel strainer used on some turbine engine aircraft have a warning device that signals the flight crew when the strainer is beginning to clog up?
Strainers clog because ice forms on the filter element. The flight crew can route the fuel through a fuel heater to melt the ice.
What must be done after a fuel system strainer has been cleaned or replaced?
The system must be tested for leaks by pressurizing the system with the boost, if one is used.
Why is it important to drain all of the fuel sumps before the first flight of the day?
Water can condense in the fuel tanks and it must be drained out before the aircraft is safe for flight.
Is the procedure of draining the sumps with the aircraft in the ground attitude an assurance that all of the water is removed from the tanks?
No, some aircraft require special procedures to remove all of the water. Refer to the Aircraft Flight Manual or Pilot’s Operating Handbook.
How does water appear in the fuel drained from the tank sumps?
Water appears as a clear globule in the bottom for the container used to collect the fuel drained from the sumps.
