# SDR CA971110004

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 6, 1997
- Submitted: March 26, 2000
- Operation: Air carrier
- Make and model: Bell 212
- Registry model: [Bell 212](https://openairdocs.org/model/bell-212) (OpenAirDocs)
- Engine: Pwa PT6T3
- System (JASC): [6310 · Engine/Transmission Coupling](https://openairdocs.org/jasc/6310)
- Part: Spiralbevel Gear
- Part number: 204040701101
- Condition: Cracked
- Location: Mating Flange
- Part time: 8,914 hours
- Component: 212040001123
- 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/CA971110004

## Discrepancy

(CAN) IN NORMAL SERVICE, THE ATTACHMENT BOLT TORQUE OF THE GEAR TO SHAFT (P/N 204-040-324-5) BECAME REDUCED RESULTING IN FRETTING CORROSION OF THE MATING SURFACES.  A SURFACE CRACK WAS FOUND DURING OVERHAUL BETWEEN TWO OF THE ATTACH BOLT HOLES IN THE GEAR.  SUBMITTER SUSPECTS THAT CRACK ONLY EXTENDS THROUGH THE SURFACE HARDENING.

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