# SDR 97ZZZX1919

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 22, 1997
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: [N6867L](https://openairdocs.org/aircraft/N6867L), registered now
- Make and model: Cessna 421C
- Registry model: [Cessna 421C](https://openairdocs.org/model/cessna-421c) (OpenAirDocs)
- Aircraft serial: 421C1087
- Engine: Cont GTSIO520N
- System (JASC): [8520 · Reciprocating Engine Power Section](https://openairdocs.org/jasc/8520)
- Part: Gear
- Part number: 653580
- Condition: Failed
- Location: Crankshaft
- Part time: 400 hours
- Stage of operation: IN
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/97ZZZX1919

## Discrepancy

NEW CRANKSHAFT GEAR P/N 653580 INSTALLED AT TIME OF ENGINE OVERHAUL IN CONJUNCTION WITH TCM SB CSB 94-4 IN KIT EQ6642. ENGINE FAILED APROXIMATELY 400.0 HOURS LATER.  ENGINE DISASSEMBLY REVEALED THE POSSIBILITY THE GEAR BROKE FIRST CAUSING DAMAGE TO VALVE TRAIN, STARTER ADAPTER GEAR, AND IDLER GEAR.

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