AMT Aircraft Fuel Systems 3

Question 1

What is the primary function of baffles installed inside aircraft fuel tanks?

Accepted Answer

To reduce fuel sloshing and maintain fuel near the outlet during aircraft maneuvering

Answer

To physically separate different grades or types of fuel stored in the same tank

Answer

To filter particulate contamination from fuel as it flows toward the outlet

Answer

To house the capacitance probes used by the electronic fuel quantity system

Question 2

During a preflight fuel sample inspection, what indicates water contamination in aviation fuel?

Accepted Answer

A distinct clear layer at the bottom or cloudiness throughout the fuel sample

Answer

A noticeably darker color than normal for the fuel grade

Answer

An unusual sulfurous odor detected from the drained sample cup

Answer

Fuel that is significantly warmer than the ambient air temperature

Question 3

What type of pump is most commonly used as the engine-driven fuel pump on piston aircraft engines?

Accepted Answer

Vane-type (rotary vane) pump

Answer

Centrifugal impeller pump

Answer

External gear pump

Answer

Diaphragm-type reciprocating pump

Question 4

What is the purpose of a firewall fuel shutoff valve in a single-engine aircraft?

Accepted Answer

To allow the pilot to immediately stop all fuel flow to the engine from the cockpit during emergencies

Answer

To regulate fuel pressure delivered to the carburetor or fuel injector system

Answer

To prevent reverse flow of fuel back toward the fuel tanks from the engine

Answer

To automatically shut off fuel if the engine-driven pump fails and boost pump takes over

Question 5

What does the 'LL' designation in AVGAS 100LL stand for?

Accepted Answer

Low Lead — indicating reduced lead content compared to 100/130 aviation gasoline

Answer

Long Life — indicating extended shelf stability compared to older grades

Answer

Light Load — referring to the fuel's lower energy density rating at altitude

Answer

Lower Limit — the octane rating represents the minimum engine performance threshold

Question 6

What is the function of an ejector pump (jet pump) used in aircraft fuel transfer systems?

Accepted Answer

To transfer fuel from auxiliary or tip tanks to main tanks using motive flow energy with no moving parts

Answer

To serve as a backup electric fuel pump if the primary boost pump fails

Answer

To filter and de-aerate fuel before it enters the engine-driven pump

Answer

To pressurize fuel tanks above ambient pressure for high-altitude cruise operation

Question 7

How does a capacitance-type fuel quantity gauging system determine fuel quantity in an aircraft tank?

Accepted Answer

By measuring the electrical capacitance between probes, which changes proportionally as the fuel-to-air ratio in the tank changes

Answer

By measuring the hydrostatic weight of fuel pressing down on pressure sensors at the tank bottom

Answer

By tracking float position linked to a variable resistor as the fuel surface rises and falls

Answer

By using ultrasonic pulses to measure the time-of-flight to the fuel surface