# SDR 2004UALA00808

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 2, 2004
- Submitted: September 8, 2004
- Operation: Air carrier
- Aircraft: [N658UA](https://openairdocs.org/aircraft/N658UA), registered now
- Make and model: Boeing 767322
- Aircraft serial: 27113
- Aircraft time: 51,648 hours, 8,526 cycles
- Engine: Pwa PW4060
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Outflow Valve
- Condition: Failed
- Location: Cabin Pressure
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: B, A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2004UALA00808

## Discrepancy

FLIGHT RETURNED TO FIELD WITH CABIN PRESSURE FAULTS. THE EQUIPMENT COOLING OVERBOARD EXHAUST VALVE FAILED. THE VALVE WAS NOT DEACTIVATED PER THE MEL CAUSING A LOSS OF CABIN PRESSURIZATION ON THE SUBSEQUENT FLIGHT. THE VALVE WAS RE-DEFERRED PER THE MEL AND REPLACED AT THE NEXT MAINTENANCE OPPORTUNITY WITH NO FURTHER PROBLEMS. LINE QA IS CONDUCTING A INVESTIGATION INTO THE CIRCUMSTANCES.

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