# SDR 2011FA0000428

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 30, 2011
- Submitted: June 30, 2011
- Operation: General aviation
- Aircraft: [N172N](https://openairdocs.org/aircraft/N172N), registered now
- Make and model: Cessna 172N
- Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (OpenAirDocs)
- Aircraft serial: 17271113
- Aircraft time: 5,832 hours
- Engine: Lyc O320H2AD
- Engine time: 1,567 hours
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Pushrod
- Part number: LW15315
- Condition: Broken
- Location: Engine
- Part time: 1,567 hours
- Stage of operation: DE
- How discovered: V
- Nature of condition: Y
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2011FA0000428

## Discrepancy

CYLINDER NR 3 EXHAUST VALVE PUSH ROD BROKE, DUE TO A STUCK VALVE IN THE CLOSED POSITION.  THE VALVE WAS NOT STUCK AT THE TIME OF THE INVESTIGATION.  NO MARKS WERE SEEN ON THE TOP OF THE PISTON AS VIEWED THROUGH A BORESCOPE.  THE SPARK PLUGS HAD ONLY SLIGHT BLACK SOOTY
APPEARANCE WITH LEAD FOWLING DEEP IN THE INSULATOR.  OTHER SPARK PLUGS HAD A TAN APPEARANCE. THE LIFTER CAME APART AS A RESULT OF THE BROKEN PUSH ROD BUT APPEARS TO HAVE BEEN OPERATING PROPERLY PRIOR TO THE EVENT.

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