# SDR HDNA2016F00191

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 21, 2016
- Submitted: September 21, 2016
- Operation: Air carrier
- Aircraft: [N145NC](https://openairdocs.org/aircraft/N145NC), registered now
- Make and model: Bolkms BK117C2
- Aircraft serial: 9542
- Aircraft time: 2,032 hours
- Engine: Tmeca ARRIEL1E2
- System (JASC): [6520 · Tail Rotor Gearbox](https://openairdocs.org/jasc/6520)
- Part: Gearbox
- Part number: 4639003011
- Part serial: 1532
- Condition: Broken
- Location: Tailboom
- Part time: 2,032 hours
- 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/HDNA2016F00191

## Discrepancy

DURING REMOVAL OF THE TAIL ROTOR GEARBOX FOR TBO CHANGE, WE FOUND THAT THE ATTACHING STUD WAS SHEARED OFF AT THE TAIL BOOM ATTACHMENT POINT.

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