# SDR 96ZZZX944

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 1, 1996
- Submitted: March 26, 2000
- Operation: Air carrier
- Aircraft: N3246M
- Make and model: Cessna 402C
- Registry model: [Cessna 402C](https://openairdocs.org/model/cessna-402c) (OpenAirDocs)
- Aircraft serial: 402C0294
- Engine: Cont TSIO520VB
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Spring
- Condition: Broken
- Location: Valve
- Part time: 75 hours
- Stage of operation: CL
- Nature of condition: E
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/96ZZZX944

## Discrepancy

PILOT REPORTED A NOTICEABLE VIBRATION SHORTLY AFTER TAKEOFF AND DURING CLIMB AND INTO CRUISE.  AFTER LANDING AT FINAL DESTINATION, MAINTENANCE PERFORMED A CYLINDER COMPRESSION CHECK.  ALL CYLINDERS ON BOTH ENGINES SHOWED NO EVIDENCE OF LEAKAGE.  AFTER FURTHER GROUND RUN-UPS, IT WAS DETERMINED TO BE THE RIGHT ENGINE.  AFTER ALL CYLINDER VALVE COVERS WERE REMOVED, A TOTAL OF 9 OUTER VALVE SPRINGS WERE FOUND BROKEN.  ALL VALVE SPRINGS WERE REPLACED, AND THE DEFECTIVE SPRINGS SENT TO TCM FOR FURTHER INVESTIGATION.

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