# SDR 2024FA0000003

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 3, 2024
- Submitted: January 3, 2024
- Operation: General aviation
- Make and model: Mooney M20TN
- Registry model: [Mooney M20TN](https://openairdocs.org/model/mooney-m20tn) (OpenAirDocs)
- Aircraft serial: 310083
- Engine: Cont TSIO550G
- System (JASC): [8520 · Reciprocating Engine Power Section](https://openairdocs.org/jasc/8520)
- Part: Rocker Boss
- Part number: UNKNOWN
- Condition: Broken
- Location: Zone 400
- Component: Engine Cylinder
- Stage of operation: CR
- How discovered: V
- Nature of condition: E, D
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2024FA0000003

## Discrepancy

PILOT REPORTED SUDDEN VIBRATION IN FLIGHT, FOLLOWED BY LOSS OF CHT/EGT ON CYLINDERS #1, #3, #5, AND LOSS OF ENGINE OIL PRESSURE.  AFTER LANDING AND REMOVING ENGINE COWLING IT WAS DISCOVERED THAT THE #3 CYLINDER EXHAUST ROCKER ARM SHAFT MOUNT STRUCTURE HAD BROKEN OFF OF THE CYLINDER HEAD AND HAD BEEN PUSHED THROUGH THE ROCKER ARM COVER.

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