Definition
A flexible drive belt, usually rubber or reinforced rubber, that transfers rotational power from a pulley on the engine to the alternator, allowing the alternator to generate electrical power for the aircraft's electrical system and to charge the battery.
Plain English
The belt that connects the engine to the alternator so the engine can spin the alternator and make electricity for the airplane.
Context Anchor
Seen in aircraft system malfunction discussions, especially when diagnosing a low-voltage warning, alternator failure, or loss of electrical power in flight.
Derivation
Alternator comes from the Latin alternare, meaning to do by turns. An alternator produces alternating current by turning, and the belt is what makes it turn.
Why Pilots Care
A failed alternator belt stops electrical generation, leading to battery drain and loss of instruments, lights, and avionics that are essential for instrument flight and safe operation.
Intuition Check
Do not think of the alternator belt as an electrical part. It is a mechanical belt; its job is to turn the alternator, not to carry electricity.
Example Sentence 1
During preflight, the pilot checked the alternator belt for proper tension and signs of fraying.
Example Sentence 2
After the alternator belt broke in flight, the pilot switched to battery power and began load shedding to conserve remaining electrical capacity.