Fuel Systems & Aircraft Plumbing Flashcards

What is the primary purpose of a fuel strainer (gascolator) in a reciprocating aircraft engine fuel system?

Answer: To remove water and sediment from fuel before it reaches the carburetor or fuel injector

A fuel strainer (gascolator) filters water and particulate contamination from the fuel before it enters the engine fuel metering system.

Why must aircraft fuel tanks be vented to atmosphere?

Answer: To prevent tank collapse or pressure differential as fuel is consumed and altitude changes

Tank venting prevents vacuum buildup as fuel is consumed and compensates for atmospheric pressure changes with altitude, preventing tank deformation and fuel flow interruption.

What type of fuel is used in most turbine-powered aircraft operated in the United States?

Answer: Jet-A (kerosene-based turbine fuel)

Jet-A is the standard turbine fuel used in most US turbine aircraft, with a flash point above 100°F and freeze point around -40°C.

What color is 100LL aviation gasoline (AVGAS) dyed, and why?

Answer: Blue, to identify it as 100 octane low lead and prevent misfueling with other grades

100LL AVGAS is dyed blue to identify it as 100 octane low lead fuel and prevent misfueling with Jet-A or other grades.

During a preflight fuel check, a pilot/mechanic finds a small amount of water in the fuel sample. The correct action is:

Answer: Continue sampling and draining until no water is found, verifying the sample is clear

When water is found in a fuel sample, continue draining and sampling from all sumps until all samples are consistently clear and free of water, then verify the quantity before flight.

What is the function of a boost pump in an aircraft fuel system?

Answer: It provides positive fuel pressure for starting, backup fuel pressure, and transfer between tanks

Electric boost pumps provide fuel pressure for engine starting, serve as backup if the engine-driven pump fails, and assist in fuel transfer between tanks.