# SDR CA190808002

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 31, 2019
- Submitted: August 17, 2020
- Operation: General aviation
- Make and model: Cessna 172M
- Registry model: [Cessna 172M](https://openairdocs.org/model/cessna-172m) (OpenAirDocs)
- Aircraft time: 27,739 hours
- Engine: Lyc O320D2J
- System (JASC): [7414 · Magneto/Distributor](https://openairdocs.org/jasc/7414)
- Part: Impulse Coupling
- Part number: M3163
- Condition: Failed
- Location: Magneto
- Component: Magneto, Champion
- Component part number: 4371
- Stage of operation: TX
- How discovered: O
- Nature of condition: R
- Precautionary procedure: D
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CA190808002

## Discrepancy

(CAN) DURING PRE-TAKEOFF GROUND RUN THE PILOT REPORTED A "DEAD RH MAG". MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND THE IMPULSE COUPLING ON THE RH MAGNETO HAD BROKEN WHICH CAUSED A SHIFT IN MAGNETO-TO-ENGINE TIMING CAUSING THE ENGINE TO NOT RUN ON THE RH MAGNETO. THE MAGNETO WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE. (TC# 20190808002)

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