# SDR SWAA112856

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 15, 2011
- Submitted: April 20, 2011
- Operation: Air carrier
- Aircraft: [N623SW](https://openairdocs.org/aircraft/N623SW), registered now
- Make and model: Boeing 737-3H4
- Registry model: [Boeing 737-3H4](https://openairdocs.org/model/boeing-737-3h4) (OpenAirDocs)
- Aircraft serial: 27933
- Aircraft time: 50,003 hours, 40,577 cycles
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Outflow Valve
- Part number: 327375
- Part serial: 0777
- Condition: Faulty
- Location: Cabin Pressure
- Stage of operation: DE
- 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/SWAA112856

## Discrepancy

AIR TURNBACK/DECLARED EMERGENCY.  PASSING FL 220 CABIN ALTITUDE HORN CAME ON UPON DESCENT.  UNABLE TO CONTROL OUTFLOW VALVE IN AUTO/ALTERNATE BUT CONTROLLABLE IN MANUAL.  REMOVED AND REPLACED OUTFLOW VALVE PER MM.

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