FAA Aviation Mechanic Powerplant (AMP)Ignition and Starting SystemsHard
A technician is performing the internal timing of a magneto prior to installing it on an engine. What is the technician trying to accomplish during this procedure?
- ASetting the magneto-to-engine timing by rotating the crankshaft to top dead center
- BAdjusting the impulse coupling flyweights to release at a specific RPM
- CAdjusting the spark plug gap to the manufacturer's specification before installation
- DSetting the breaker points to open exactly at the E-gap position using a timing light or buzzer box
Show answer & explanationAnswer & explanation
Correct answer: D. Setting the breaker points to open exactly at the E-gap position using a timing light or buzzer box
Internal timing sets the breaker points to open precisely at the E-gap position (the point of maximum rate of flux change) using a timing light, buzzer box, or similar continuity device, independent of the engine; this is done before the magneto is mounted and timed to the engine.
Why the other options are wrong
- A. Timing the magneto to the crankshaft (external timing) is a separate step done after internal timing.
- B. Impulse coupling flyweight adjustment is not part of internal timing.
- C. Spark plug gap adjustment is unrelated to internal magneto timing.
Magneto Internal Timing
The process of setting a magneto's breaker points to open exactly at the E-gap position (point of maximum flux change) using a timing light or buzzer box, performed before the magneto is installed and timed to the engine.
- Done off the engine using a timing fixture
- Precedes external timing to the crankshaft
- Ensures maximum voltage output at points opening
Memory trick: Internal timing = tuning the magneto's own clock before syncing it to the engine