# SDR QR9R20210611001

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 11, 2021
- Submitted: June 11, 2021
- Operation: General aviation
- Filed by: [M1 Support Services, repair station QR9R369D](https://openairdocs.org/faa-repair-station/QR9R369D/m1-support-services.md) (OpenAirDocs)
- Make and model: Bolkms BK117C2
- System (JASC): [6420 · Tail Rotor Head](https://openairdocs.org/jasc/6420)
- Part: Bearing
- Part number: 1053170023
- Condition: Out Of Tolerance
- Location: T/R Head
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/QR9R20210611001

## Discrepancy

SYSTEMIC AND PREMATURE FAILURE OF THE T/R HEAD SPHERICAL BEARINGS RESULTING IN EXCESSIVE RADIAL PLAY AND TAIL ROTOR VIBRATIONS.

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