Explanations: Aircraft Fuel Systems Flashcards
Describe the interior of a boost pump.
Nah, just go watch a video on it.
What are dump limit valves?
fuel tanks whose fuel can be jettisoned are equipped with a dump limit switch that will shut off the flow to the dump chute if the pressure drops below what is needed to supply the engine with adequate fuel, or when the tank level reaches a preset dump shutoff level.
Why should the outboard wing tanks be defueled first?
This procedure minimizes the twisting effect on the wing caused by the fuel being located behind the wing attachment points on the fuselage.
How do flapper valves operate?
They are normally open, but if a maneuver causes the fuel to flow away from the pump or outlet, they flap shut until the force moving the fuel no longer exists, then they automatically reopen.
What is a transducer?
A device that changes energy from one form into another.
A fuel pressure transducer converts fuel pressure into an electrical signal that is proportional to the fuel pressure. This signal is transmitted to the fuel pressure indicator.
How do boost pumps prevent bubbles from entering the fuel lines?
Boost pumps installed in many aircraft fuel tanks have an agitator on their shaft along with the impeller. The agitator causes bubbles in the fuel to be released into the tank before the fuel is forced into the fuel lines. The boost pumps hold a pressure on the fuel in the lines to prevent additional vapors from forming.
What inclusion allows an aircraft to be fueled by the pressure fueling method?
the inclusion of a manifold fuel system.
All of the tanks can be fueled at the same time through a single manifold connection. This reduces the fueling time, minimizes the chance of contamination, and minimizes the buildup of static electrical charges.
Why does a fuel tank need to maintain atmospheric pressure?
It maintains atmospheric pressure on to of the fuel in the tank to provide for proper fuel flow from the tank to the engine.
What should be done before a gas tank is welded?
It should be washed out with hot water and a detergent. Then, live steam should be passed through the tank for about a half hour.
This treatment vaporizes and removes any residual fuel that may be left in the tank.
Why does the RPM slightly increase before an engine starts to die when the mixture control is switched into the idle cutoff position?
Because an engine normally operates using an idling fuel-air mixture richer than that which produces the most efficient burning. When the mixture is cutoff, it passes through the ratio that produces the best burning. The RPM picks up a few RPMs before it drops off completely.
What do anti-icing additives accomplish?
they are put in turbine fuel to lower the freezing temperature of the water and prevent its freezing on the filters.
Most jet transport aircrafts have fuel heaters, or heat exchangers, that use engine compressor bleed air or engine oil to raise the temperature of the fuel enough that it will not freeze on the filters.
Is a stain, seep, or heavy seep a flight hazard in a well ventilated area of the aircraft?
No. In order for it to be a flight hazard, the fumes must collect in an unventilated area.
How does a drip gauge work?
the drip gauge is pulled down from the bottom of the tank until fuel begins to drip from its end. The quantity of fuel in the tank is indicated on the gauge by the amount the gauge is pulled from the tank before it begins to drip.
An electronic (capacitance-type) fuel quantity indicating system contains what parts?
Capacitor probes, mounted in the tanks
a bridge circuit to measure the capacity of the probes
an amplifier to increase the amplitude of the signal from the bridge circuit to a value high enough to drive the indicator.
an indicator mounted in the instrument panel to show the amount of fuel in the tanks.
