# SDR AALA202601044587

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 1, 2026
- Submitted: January 4, 2026
- Operation: Air carrier
- Aircraft: [N521UW](https://openairdocs.org/aircraft/N521UW), registered now
- Make and model: Airbus A321-231
- Registry model: [Airbus A321-231](https://openairdocs.org/model/airbus-a321-231) (OpenAirDocs)
- Aircraft serial: 3944
- Aircraft time: 53,311 hours, 20,504 cycles
- System (JASC): [2120 · Air Distribution System](https://openairdocs.org/jasc/2120)
- Part: Packing
- Part number: M832481011
- Condition: Leaking
- Location: Zone 100
- Stage of operation: CL
- How discovered: O
- Nature of condition: B
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA202601044587

## Discrepancy

AIRCRAFT WAS GROUNDED: AIRCRAFT DIVERTED TO PHX DUE TO THE FLIGHT CREW REPORTING THAT DURING CLIMBOUT THERE WAS A STRONG ODOR OF CHEESE OR DIRTY SOCKS IN THE FLIGHT DECK AND THE ENTIRE CABIN. THE FLIGHT CREW LEVELED OFF AT 27, 000 BUT THE ODOR REMAINED. THE FLIGHT CREW DID NOT DECLARE AN EMERGENCY AND LANDED THE AIRCRAFT AT PHX WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND THE APU CHIP DETECTOR LEAKING AND REPLACED THE O-RINGS PER AMM 49-91-42. A SATISFACTORY LEAK CHECK WAS ACCOMPLISHED WITH NO LEAKS OR ODORS NOTED.

---
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.