A&P - Aircraft and Powerplant Aircraft Electrical Systems Questions and Answers

Question 1

In a typical light aircraft electrical system, what is the primary function of the voltage regulator?

Accepted Answer

To maintain a constant voltage output from the generator/alternator under varying engine speeds and electrical loads.

Answer

To convert alternating current (AC) to direct current (DC).

Answer

To prevent the battery from overcharging by disconnecting it from the bus bar.

Answer

To step up the voltage for the ignition system.

Question 2

A technician is troubleshooting a circuit where the circuit breaker trips immediately upon closing the switch, even with the electrical component disconnected. Which of the following is the MOST likely cause?

Accepted Answer

A short circuit to ground between the switch and the component.

Answer

A defective circuit breaker.

Answer

An open circuit in the wiring.

Answer

The electrical component has an internal short.

Question 3

Which of the following is a key difference between a fuse and a circuit breaker in an aircraft electrical system?

Accepted Answer

A fuse must be replaced after it opens the circuit, while a circuit breaker can typically be reset.

Answer

A fuse can be reset multiple times, whereas a circuit breaker must be replaced after tripping.

Answer

A circuit breaker is designed to protect against over-voltage, while a fuse protects against over-current.

Answer

A circuit breaker operates on thermal principles, while a fuse is electromagnetic.

Question 4

According to 14 CFR Part 23, what is required for an aircraft's electrical system regarding its power sources?

Accepted Answer

No failure or malfunction of any one power source may impair the ability of any remaining source to supply power to loads essential for safe operation.

Answer

A single generator is sufficient for all flight operations, provided it has a backup battery.

Answer

The battery must be capable of powering all electrical equipment for at least 60 minutes.

Answer

All power sources must be manually switchable by the flight crew.

Question 5

What is the purpose of a bus bar in an aircraft electrical system?

Accepted Answer

To serve as a common distribution point for electrical power to various circuits.

Answer

To generate electrical power.

Answer

To store electrical energy for emergency use.

Answer

To regulate the current flowing to the battery.

Question 6

A technician measures the specific gravity of the electrolyte in a fully charged lead-acid battery. What reading would be considered normal?

Accepted Answer

1.275 to 1.300

Answer

1.100 to 1.150

Answer

1.200 to 1.250

Answer

1.325 to 1.350