# SDR 2026FA0000599

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 7, 2026
- Submitted: July 24, 2026
- Operation: General aviation
- Aircraft: [N647LA](https://openairdocs.org/aircraft/N647LA), registered now
- Make and model: Airtrc AT502B
- Aircraft serial: 502B2347
- Aircraft time: 7,277 hours
- System (JASC): [3210 · Main Landing Gear](https://openairdocs.org/jasc/3210)
- Part: Cotter Pin
- Condition: Missing
- Location: Zone 700
- Component: Wheel Assembly
- Stage of operation: LD
- How discovered: O
- Nature of condition: E
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2026FA0000599

## Discrepancy

DURING TAKEOFF, THE PIC REPORTED A BUFFERING IN THE LEFT BRAKE JUST PRIOR TO TAKEOFF.  DURING LANDING, THE PIC REPORTED A SIGNIFICANT DIFFERENCE IN BRAKING AUTHORITY BETWEEN THE RIGHT AND LEFT SIDE WHICH RESULTED IN THE AIRCRAFT DEPARTING THE RUNWAY INTO THE DIRT.  IT WAS IDENTIFIED THAT THE LEFT WHEEL BEARING, RETAINING NUT, AND COTTER PIN HAD SEPARATED FROM THE AIRCRAFT FOR UNKNOWN REASONS.  IT IS UNCLEAR WHETHER THIS WAS DUE TO A FAILED OR MISSING COTTER PIN.

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