# SDR ALGA031211278AL

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 12, 2011
- Submitted: March 16, 2011
- Operation: Air carrier
- Aircraft: [N278AL](https://openairdocs.org/aircraft/N278AL), registered now
- Make and model: Bell 206L-4
- Registry model: [Bell 206L-4](https://openairdocs.org/model/bell-helicopter-textron-canada-206l-4) (OpenAirDocs)
- Aircraft serial: 52313
- Aircraft time: 7,275 hours
- System (JASC): [6510 · Tail Rotor Drive Shaft](https://openairdocs.org/jasc/6510)
- Part: Nut
- Condition: Cracked
- Location: T/R Drive Assy
- 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/ALGA031211278AL

## Discrepancy

DURING ROUTINE INSP, MX FOUND 2 NUTS PN MS21042L4 CRACKED.  THE NUTS WERE A PART OF THE HARDWARE STACKUP ATTACHING THE TAILROTOR DRIVESHAFT FLEX COUPLINGS TO THE DRIVESHAFT.  THE NUTS HAD A VENDOR STAMP MARK RESEMBLING AN "A" OR A "V" TURNED SIDEWAYS ON ONE OF THE WRENCH FLATS. FURTHER INVESTIGATION SHOWED THE THREADS ON THE "SKIRT" OR FLANGE END OF THE NUTS TO BE SUB-PAR. VISUAL INSP OF NEW HARDWARE IN STOCK REVEALED THE SAME ANOMOLIES.

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