# SDR 2007UALA04837

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 26, 2007
- Submitted: November 30, 2007
- Operation: Air carrier
- Aircraft: [N171UA](https://openairdocs.org/aircraft/N171UA), registered now
- Make and model: Boeing 747422
- Aircraft serial: 24322
- Aircraft time: 69,465 hours, 8,406 cycles
- Engine: Pwa PW4056
- System (JASC): [3510 · Crew Oxygen System](https://openairdocs.org/jasc/3510)
- Part: Valve
- Condition: Faulty
- Location: Crew Rest O2
- Stage of operation: IN
- How discovered: C
- Nature of condition: W
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2007UALA04837

## Discrepancy

UPPER AFT CREW REST FWD LWR BUNK, O2 MASK DOOR WILL NOT OPEN, WITH OPS CK OF THE FLOW CONTROL UNITS.  SUSPECT FAULTY VALVE ASSEMBLY.  REPLACED UNITIZED VALVE ASSEMBLY. REF MM 35-21-36.  AC OK FOR SERVICE.

---
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.