# SDR 2026FA0000798

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 30, 2026
- Submitted: September 30, 2026
- Operation: General aviation
- Aircraft: [N735CB](https://openairdocs.org/aircraft/N735CB), registered now
- Engine: Allsn 250C20B
- Engine time: 8,822 hours, 11,668 cycles
- System (JASC): [7200 · Engine (Turbine/Turboprop)](https://openairdocs.org/jasc/7200)
- Part: Lock Nut
- Part number: MS21043
- Condition: Failed
- Location: Engine
- Stage of operation: IN
- How discovered: V
- Nature of condition: Z
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2026FA0000798

## Discrepancy

MS21043 NUTS ARE UTILIZED TO SECURE TURBINE, COMPRESSOR, FUEL CONTROL, GOVERNOR, AND HAVE BEEN FOUND NUMEROUS TIMES TO HAVE NOT MAINTAINED THE MANUAL SPECIFIED TORQUE AND HAVE BACKED OFF. NUMEROUS TIMES NUTS HAVE ARRIVED WITHOUT ANY DRAG TORQUE. THE LOCKING FEATURE OF THE NUT IS FAILING. MANUFACTURER IS MONROE AEROSPACE AND LOT NUMBERS ARE NOT CONSISTENT AS THOUGH IT WAS A BAD LOT.

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