Aircraft Fuel Systems Flashcards
6 cards from real A&P practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Aircraft Fuel Systems flashcards as text
What is the hazard of misfueling a piston aircraft with Jet-A fuel instead of 100LL AVGAS?
Answer: Jet-A will not ignite reliably in a spark-ignition engine, leading to power loss or engine stoppage
Jet-A's high flash point means it will not vaporize or ignite properly in a spark-ignition piston engine, resulting in power loss, rough running, or engine failure.
What is the purpose of a fuel system water separator on a turbine aircraft?
Answer: To remove free water from the fuel stream before it reaches the engine fuel control unit
A fuel/water separator removes free (undissolved) water from turbine fuel to prevent fuel control unit damage, ice formation in fuel nozzles, and combustion instability.
When must the fuel cap be replaced on an aircraft with an integral (wet wing) fuel tank after servicing?
Answer: Immediately after fueling; the tank must not be left uncapped for any reason during maintenance breaks
Fuel caps must be reinstalled and secured immediately after servicing to prevent fuel spillage, contamination, or vapor ignition, and the aircraft must not be left unattended with open fuel caps.
What is the purpose of a fuel flow divider (distributor) on a fuel-injected reciprocating engine?
Answer: To evenly distribute fuel to all individual fuel injector nozzles at equal pressure
The flow divider (manifold valve or spider) distributes metered fuel equally among all fuel injection nozzles to ensure uniform fuel delivery to each cylinder.
What is the significance of fuel quantity gauges being required to read accurately only at EMPTY in FAR Part 23 aircraft?
Answer: It means gauges are only required to be accurate at the empty indication; readings at other levels may be inaccurate, so preflight fuel verification by visual inspection or dipstick is essential
FAR 23.1337 requires that fuel gauges read zero at the unusable fuel quantity level; the gauge need not be accurate at higher quantities, making physical verification critical.
What is unusable fuel, and why is it listed in the aircraft weight and balance data?
Answer: Fuel that cannot be safely consumed in flight due to system design (e.g., below the fuel pickup tube); it is listed because it counts as aircraft empty weight
Unusable fuel is the residual quantity trapped below the fuel pickup point that cannot feed the engine; it is part of the licensed empty weight and must be included in weight and balance calculations.