A&P A&P - Aircraft and Powerplant Aircraft Fuel Systems

Question 1

What grade of aviation gasoline (avgas) is identified by its blue color?

Accepted Answer

100LL (low-lead)

Answer

100LL avgas is dyed blue for identification and is the most widely used grade for piston-powered aircraft.

Question 2

What is the primary purpose of a fuel system boost pump?

Accepted Answer

Provide positive fuel pressure to the engine-driven pump and prevent vapor lock

Answer

Boost pumps supply positive inlet pressure to the engine-driven pump and prevent vapor lock, especially during takeoff and high-altitude operations.

Question 3

What does a fuel selector valve set to 'BOTH' mean on a single-engine aircraft with two wing tanks?

Accepted Answer

Fuel is drawn from both tanks simultaneously through a crossfeed manifold

Answer

The BOTH position opens both tank feeds simultaneously, drawing fuel from both wing tanks at the same time.

Question 4

Where is the fuel tank sump drain located and why?

Accepted Answer

At the lowest point of the tank to collect and drain water and sediment

Answer

The sump drain is at the lowest point of the fuel tank so that water, which is denser than fuel, accumulates there and can be drained during preflight.

Question 5

What is the maximum allowable water contamination check procedure during aircraft preflight?

Accepted Answer

Drain a sample from each sump into a clear container and visually check for water globules or cloudiness

Answer

Preflight fuel sampling involves draining fuel into a clear tester and checking visually for water (appears as globules or cloudiness at the bottom).

A&P - Aircraft and Powerplant Certification Practice Test

A&P - Aircraft and Powerplant Certification Practice Test

A&P A&P - Aircraft and Powerplant Aircraft Fuel Systems