Definition
The rotating electrode inside a magneto's distributor that routes the high-voltage spark from the magneto coil to the correct spark plug lead in the firing order. As the engine turns, the distributor finger spins past stationary contacts, sending each high-voltage pulse to the spark plug for the cylinder that is ready to fire.
Plain English
A small spinning arm inside the magneto that points the spark to the right spark plug at the right moment, so each cylinder fires in turn.
Context Anchor
Seen in aircraft ignition system discussions, magneto inspections, and engine troubleshooting.
Derivation
Called a 'finger' because of its shape — a slim, pointing arm that sweeps around and 'points' the spark at each contact in turn. 'Distributor' comes from Latin distribuere, 'to divide and hand out,' which is exactly what it does with the spark.
Why Pilots Care
Ensures each cylinder fires at the precise moment for smooth engine operation and power delivery.
Intuition Check
Do not read finger as a human body part here. In this context, it means a small arm-like electrical contact that rotates and directs the spark.
Example Sentence 1
During the 100-hour inspection, the mechanic found a hairline crack in the distributor finger and replaced it before returning the magneto to service.
Example Sentence 2
A damaged distributor finger can cause misfiring in specific cylinders.