Airframe Mechanic Certification Powerplant Systems & Maintenance 4

Question 1

What is the function of a propeller governor?

Accepted Answer

Maintain a selected RPM by varying propeller pitch

Answer

The propeller governor maintains a pilot-selected RPM by increasing or decreasing blade pitch as engine power or airspeed changes.

Question 2

Carburetor icing most commonly forms:

Accepted Answer

At temperatures between approximately -7°C and 21°C with high humidity

Answer

Carburetor ice can form at temperatures between -7°C and 21°C (20°F–70°F) when humidity is high due to fuel evaporation and venturi cooling effects.

Question 3

An oil analysis report showing a sudden spike in iron particles most likely indicates:

Accepted Answer

Wear or damage in ferrous engine components such as cylinder walls or gears

Answer

Iron particles in oil analysis indicate wear or damage to ferrous metal engine components and warrant investigation before further flight.

Question 4

What happens to mixture requirements as altitude increases in a non-turbocharged reciprocating engine?

Accepted Answer

Mixture must be leaned because air density decreases

Answer

As altitude increases, air density decreases so less air enters the engine, requiring the mixture to be leaned to maintain the proper fuel-air ratio.

Question 5

A turbine engine's N1 speed refers to:

Accepted Answer

Low-pressure compressor (fan) and turbine spool speed

Answer

N1 represents the rotational speed of the low-pressure spool, which includes the fan (in turbofans) and associated low-pressure turbine stages.

Airframe Mechanic Certification Practice Test