Aircraft Electrical Systems Flashcards
7 cards from real AMT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Aircraft Electrical Systems flashcards as text
In aircraft wiring, what is the maximum allowable voltage drop across a continuously operating essential bus feeder cable?
Answer: 1 volt
FAA and manufacturer guidelines generally limit voltage drop on continuously operating essential circuits to no more than 1 volt to ensure reliable equipment operation.
Which battery type is most commonly used in modern transport-category aircraft because of its high power-to-weight ratio and lack of sulfation?
Answer: Nickel-cadmium (NiCd)
Nickel-cadmium batteries are preferred in transport aircraft for their ability to deliver high current, resistance to sulfation, and stable performance across temperature extremes.
A thermal runaway condition in an aircraft NiCd battery is characterized by:
Answer: Self-sustaining rise in temperature and charge current that can lead to fire
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.
When routing electrical wiring through aircraft structure, wires should be installed to avoid:
Answer: Areas where chafing against structure or other lines could damage insulation
Chafing against sharp edges, structural members, or other systems is a primary cause of wire insulation damage leading to shorts and fires.
What is the purpose of a split-bus or essential bus architecture in aircraft electrical design?
Answer: To isolate critical flight instruments and avionics so they remain powered even if the main bus fails
A split-bus or essential bus ensures flight-critical instruments retain power from the battery even if the main bus or generator fails.
According to FAR/AC guidance, aircraft electrical wire splices within a bundle should be:
Answer: Staggered so that no two splices are at the same location
Staggering splices prevents a concentration of bundle diameter increase and reduces the risk of multiple connection failures at the same point.
In a parallel generator system on a multi-engine aircraft, 'load sharing' or 'paralleling' ensures that:
Answer: All generators share the total electrical load equally to prevent one unit from overloading
Load sharing circuitry adjusts each generator's output so they carry equal portions of the total bus load, preventing one generator from overloading while another is lightly loaded.