Aircraft Electrical Systems Flashcards

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

Answer: To distribute electrical power to multiple circuits from a common point

A bus bar serves as a common distribution point that connects the power source to multiple branch circuits throughout the aircraft.

A constant-speed drive (CSD) on an aircraft generator is used to:

Answer: Maintain a constant generator RPM regardless of engine speed

The CSD maintains a constant generator input speed so the generator produces a stable AC frequency (typically 400 Hz) regardless of engine throttle setting.

Which type of wire insulation is most resistant to high temperatures in an aircraft engine compartment?

Answer: PTFE (polytetrafluoroethylene)

PTFE (commonly known as Teflon) offers excellent high-temperature resistance and is widely used in engine compartment wiring where thermal stress is significant.

What does the term 'electrical bonding' mean in aircraft maintenance?

Answer: Ensuring all metallic parts are at the same electrical potential

Electrical bonding connects all metallic components to a common ground potential to prevent static charge buildup and reduce EMI.

In a 28-volt DC aircraft system, what minimum voltage at the battery indicates a fully charged state?

Answer: 28.0 volts

A fully charged 28V aircraft battery should read approximately 28 volts at rest; readings below this indicate a partial or discharged state.

A circuit breaker that 'trips' repeatedly under normal load conditions most likely indicates:

Answer: A short circuit or overload in the downstream circuit

Repeated tripping under normal load points to a fault — typically a short circuit or a component drawing more current than the circuit is designed to handle.

Which instrument is used to measure insulation resistance of aircraft wiring?

Answer: Megohmmeter (megger)

A megohmmeter applies high voltage (typically 500V or 1000V) to test wiring insulation integrity, measuring resistance in megohms.