AMT Aircraft Electrical Systems 5

Question 1

In aircraft wiring, what is the maximum allowable voltage drop across a continuously operating essential bus feeder cable?

Accepted Answer

1 volt

Answer

FAA and manufacturer guidelines generally limit voltage drop on continuously operating essential circuits to no more than 1 volt to ensure reliable equipment operation.

Question 2

Which battery type is most commonly used in modern transport-category aircraft because of its high power-to-weight ratio and lack of sulfation?

Accepted Answer

Nickel-cadmium (NiCd)

Answer

Nickel-cadmium batteries are preferred in transport aircraft for their ability to deliver high current, resistance to sulfation, and stable performance across temperature extremes.

Question 3

A thermal runaway condition in an aircraft NiCd battery is characterized by:

Accepted Answer

Self-sustaining rise in temperature and charge current that can lead to fire

Answer

Thermal runaway occurs when heat lowers internal resistance, increasing current which generates more heat — a positive feedback loop that can destroy the battery and cause fire.

Question 4

When routing electrical wiring through aircraft structure, wires should be installed to avoid:

Accepted Answer

Areas where chafing against structure or other lines could damage insulation

Answer

Chafing against sharp edges, structural members, or other systems is a primary cause of wire insulation damage leading to shorts and fires.

Question 5

What is the purpose of a split-bus or essential bus architecture in aircraft electrical design?

Accepted Answer

To isolate critical flight instruments and avionics so they remain powered even if the main bus fails

Answer

A split-bus or essential bus ensures flight-critical instruments retain power from the battery even if the main bus or generator fails.

(AMT) Aviation Maintenance Technician Practice Test

(AMT) Aviation Maintenance Technician Practice Test

AMT Aircraft Electrical Systems 5