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.
Plain English
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.
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.
Why Pilots Care
If these belts slip or break, the alternator or generator stops producing power, the battery begins to discharge, and electrical instruments and systems can fail during flight.
Analogy
Like the serpentine belt under a car hood that spins the alternator to keep the battery charged while the engine runs.
Intuition Check
Do not read “drive belts” as seat belts or anything used by the pilot to steer. Here, “drive” means the belt is carrying engine motion to another part so that part can spin.
Example Sentence 1
During preflight, the pilot checked the alternator/generator drive belts for proper tension and visible cracks.
Example Sentence 2
A failed drive belt forced an immediate diversion when the electrical system began running solely on battery power.