# SDR 2A6D2015061011728

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 10, 2015
- Submitted: June 10, 2015
- Operation: Air carrier
- Filed by: [Air Methods LLC, repair station 2A6D933B](https://openairdocs.org/faa-repair-station/2A6D933B/air-methods-llc.md) (OpenAirDocs)
- Aircraft: [N911AL](https://openairdocs.org/aircraft/N911AL), registered now
- Make and model: Bell 407
- Registry model: [Bell 407](https://openairdocs.org/model/bell-helicopter-textron-canada-407) (OpenAirDocs)
- Aircraft serial: 53144
- Aircraft time: 8,936 hours, 29,822 cycles
- Engine: Allsn 250C47B
- System (JASC): [6320 · Main Rotor Gearbox](https://openairdocs.org/jasc/6320)
- Part: Duplex Bearing
- Part number: 407340032101
- Part serial: ZS11728
- Condition: Damaged
- Location: Mr Transmission
- Part time: 624 hours
- Component: Mr Transmission, Bell
- Component part number: 407040006115FM
- Stage of operation: AA
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2A6D2015061011728

## Discrepancy

MAIN TRANSMISSION HAD A CHIP LIGHT ILLUMINATE.  MAIN TRANSMISSION WAS SENT TO THE OVERHAUL SHOP.  UPON DISASSEMBLY IT WAS DISCOVERED THE DUPLEX BEARING FOR THE GEAR SHAFT ASSEMBLY WAS STALLING & IS THE SOURCE OF METAL CONTAMINATION IN THE TRANSMISSION.  APPROX 1 INCH ON THE OUTER BEARING RACE IS WHERE THE METAL WAS COMING FROM.

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