AMT Aircraft Fuel Systems 1 — Questions and Answers
Question 1: What type of fuel is used in most turbine-powered aircraft?
- Jet-A (Correct answer)
- AVGAS 100LL
- AVGAS 80
- Jet-B
Correct answer: Jet-A
Jet-A is the standard turbine fuel used in most commercial and turbine-powered aircraft due to its high flash point, energy density, and wide availability.
Question 2: What is the primary purpose of an electric fuel boost pump in aircraft fuel systems?
- To filter contaminants before fuel reaches the engine
- To provide positive fuel pressure during start and prevent vapor lock at altitude (Correct answer)
- To regulate fuel temperature in high-altitude cruise
- To measure and indicate fuel quantity to the cockpit
Correct answer: To provide positive fuel pressure during start and prevent vapor lock at altitude
Boost pumps supply positive inlet pressure to the engine-driven pump, ensuring adequate fuel flow during engine start and preventing vapor lock at high altitudes where atmospheric pressure is low.
Question 3: What is the most common material used in the construction of aircraft integral fuel tanks?
- Stainless steel
- Aluminum alloy (Correct answer)
- Titanium
- Fiberglass-reinforced composite
Correct answer: Aluminum alloy
Aluminum alloy is the standard material for aircraft fuel tanks because it is lightweight, corrosion-resistant when in contact with aviation fuels, and provides excellent structural integrity.
Question 4: What is the function of a fuel primer in a reciprocating aircraft engine?
- To purge residual water from the fuel lines before start
- To inject raw fuel directly into the engine cylinders or intake to aid cold starts (Correct answer)
- To pressurize the fuel tanks prior to engine start
- To test fuel quality and detect contamination
Correct answer: To inject raw fuel directly into the engine cylinders or intake to aid cold starts
A fuel primer injects raw fuel directly into the engine cylinders or intake manifold, enriching the mixture to the point where ignition can occur during cold-weather engine starting.
Question 5: What does a fuel flow indicator measure on a turbine-powered aircraft?
- Fuel temperature at the engine inlet
- Remaining fuel quantity across all tanks
- Rate of fuel consumption, typically in pounds per hour (Correct answer)
- Fuel pressure differential across the main filter
Correct answer: Rate of fuel consumption, typically in pounds per hour
A fuel flow indicator measures the rate at which fuel is being consumed, expressed in pounds per hour (turbine) or gallons per hour (piston), which is critical for fuel planning and engine performance monitoring.
Question 6: What is the minimum acceptable fuel grade for a piston engine certificated for 100 octane aviation gasoline?
- 80 octane AVGAS
- 91/96 octane AVGAS
- 100LL or 100/130 aviation gasoline (Correct answer)
- 115/145 aviation gasoline only
Correct answer: 100LL or 100/130 aviation gasoline
An engine approved for 100 octane fuel must use at least 100LL or 100/130 AVGAS; using a lower grade risks detonation, pre-ignition, and severe internal engine damage.
Question 7: What is the primary purpose of fuel tank vents on aircraft?
- To release excess fuel overflow during ground refueling operations
- To allow air to enter as fuel is consumed, preventing vacuum formation that restricts flow (Correct answer)
- To prevent moisture from entering the fuel tank from outside
- To equalize pressure between multiple fuel tanks during crossfeed
Correct answer: To allow air to enter as fuel is consumed, preventing vacuum formation that restricts flow
Tank vents allow ambient air to replace fuel as it is consumed, preventing a negative pressure (vacuum) that would restrict fuel flow to the engine and potentially collapse flexible tank bladders.
AMT Aircraft Fuel Systems 1
What type of fuel is used in most turbine-powered aircraft?