# SDR AALA202610268517

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 24, 2026
- Submitted: October 27, 2026
- Operation: Air carrier
- Aircraft: [N820NN](https://openairdocs.org/aircraft/N820NN), registered now
- Make and model: Boeing 737823
- Aircraft serial: 29559
- Aircraft time: 49,510 hours, 21,185 cycles
- System (JASC): [2751 · Trailing Flap Position Indicating System](https://openairdocs.org/jasc/2751)
- Part: Sensor
- Part number: 9000421
- Condition: Inoperative
- Location: Zone 500
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA202610268517

## Discrepancy

AIRCRAFT WAS GROUNDED:   EMERGENCY DECLARED; AIRCRAFT LANDED WITHOUT INCIDENT,  DECISION WAS MADE TO RETURN TO LAX,   AFTER TAKEOFF ON DEPARTURE AND DURING FLAP RETRACTION NOTICED FLAP ASYMMETRY AND IMMEDIATELY RESET FLAP LEVER TO 1. HELD AND RAN QRH PROCEDURE AND AFTER BURNING FUEL AND DECLARING AN EMERGENCY.   T/S FLAP ASYMMETRY FAULT IAW FIM TASK 27-59-00 FOUND FLAP SKEW SENSOR NR 4 FAULT CODE 27-53253 SKEW RESOLVER OUT OF TOLERANCE. REMOVED AND REPLACED NR 4 SKEW SENSOR IAW AMM 27-59-01.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.