Home › Topics › Engine Electrical Systems

Engine Electrical Systems: Powerplant practice questions

Five original questions on engine electrical systems, each with the answer, an explanation and an FAA-H-8083-32B page reference.

1. Voltage drop in the main power cables from the generator or battery to the bus should not exceed what?
  1. 2 percent of the regulated voltage
  2. 10 percent of the regulated voltage
  3. 1 volt regardless of system
Show answer

A. 2 percent of the regulated voltage This limit applies with the generator carrying rated current.

Reference: FAA-H-8083-32B, Ch. 4, p. 4-50

2. How can you tell a generator or alternator is not overloaded?
  1. The ammeter reading never exceeds the red line except for short, intermittent loads
  2. The battery is warm
  3. The voltmeter reads zero
Show answer

A. The ammeter reading never exceeds the red line except for short, intermittent loads The regulator does not limit maximum current, so load must be monitored.

Reference: FAA-H-8083-32B, Ch. 4, p. 4-70

3. Electric starting systems for gas turbine aircraft are of which two general types?
  1. Direct cranking and starter-generator
  2. Inertia and cartridge
  3. Hand-crank and pneumatic
Show answer

A. Direct cranking and starter-generator Starter-generators serve as the starter and then as the generator once the engine runs.

Reference: FAA-H-8083-32B, Ch. 5, p. 5-10

4. Besides current-carrying capacity, what is a second factor in choosing wire size?
  1. Permissible voltage drop (IR drop)
  2. Insulation color
  3. Number of terminals
Show answer

A. Permissible voltage drop (IR drop) Larger conductors reduce drop but cost and weigh more.

Reference: FAA-H-8083-32B, Ch. 4, p. 4-48

5. What is important when replacing an aircraft generator?
  1. Choosing one with the proper ratings
  2. Choosing the lightest one available
  3. Reusing the old brushes
Show answer

A. Choosing one with the proper ratings The replacement must match the system's required ratings.

Reference: FAA-H-8083-32B, Ch. 4, p. 4-13

Want the full kit?

355 original questions with handbook citations, 385 flashcards, 20 interactive diagrams and timed mocks scored by ACS area. $29 one-time, 14-day refund. The free sample covers reciprocating engines and ignition, with no account or card needed.

Start the free sample See pricing

Take the free 20-question practice test · All topics

What does the Powerplant test cover on engine electrical systems?

The Aviation Mechanic Powerplant ACS lists engine electrical systems as one of its areas. The FAA reference for this material is FAA-H-8083-32B.