Plain English Meaning

These are the belts that connect the engine to the part that makes electricity. The engine spins, the belt spins the alternator or generator, and that produces the electrical power the aircraft uses.

Full Definition

Rubber or composite belts that transfer rotational power from the engine crankshaft pulley to the alternator or generator pulley, enabling the alternator or generator to produce electrical power for the aircraft.

Context Anchor

Seen during engine-system study and, on aircraft where the belts are visible or accessible, during preflight or maintenance inspection.

Derivation

“Alternator” comes from “alternate,” because it produces alternating electrical current. “Generator” comes from a word meaning “to produce.” “Drive” here means to make something turn, so the term points to belts that make the electrical power unit turn.