# SDR 2018FA0000303

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 25, 2018
- Submitted: July 30, 2018
- Operation: General aviation
- Aircraft: [N549RQ](https://openairdocs.org/aircraft/N549RQ), registered now
- Make and model: Bell 412EP
- Registry model: [Bell 412EP](https://openairdocs.org/model/bell-textron-canada-412ep) (OpenAirDocs)
- Aircraft serial: 37005
- Aircraft time: 28 hours, 81 cycles
- System (JASC): [6320 · Main Rotor Gearbox](https://openairdocs.org/jasc/6320)
- Part: Bevel Gear
- Condition: Worn
- Location: M/R Transmission
- Part time: 28 hours, 81 cycles
- Component: M/R Transmissio, Bell
- Component part number: 412040007101
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2018FA0000303

## Discrepancy

DURING ROUTINE MAINTENANCE / MODIFICATION IT WAS VISUALLY NOTED THAT THERE WAS AN ABNORMAL WEAR PATTERN ON THE SPIRAL BEVEL GEAR INSIDE THE MAIN ROTOR TRANSMISSION ASSY P/N 412-040-007-101 S/N BH282157. TECHNICAL SUPPORT WAS CONTACTED, AND VERIFIED THE ABNORMAL WEAR. THE TRANSMISSION HAS BEEN REMOVED AND SHIPPED TO BELL FOR FURTHER EVALUATION.

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