# SDR SWAA990323

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 18, 1999
- Submitted: March 26, 2000
- Operation: Air carrier
- Aircraft: N600WN
- Make and model: Boeing 737-3H4
- Registry model: [Boeing 737-3H4](https://openairdocs.org/model/boeing-737-3h4) (OpenAirDocs)
- Aircraft serial: 27694
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Outflow Valve
- Part number: 40631997201AA
- Condition: Failed
- Location: Cabin
- Stage of operation: CR
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/SWAA990323

## Discrepancy

AFTER 10 MIN AT 37,000 FT CABIN ALTITUDE BEGAN CLIMBING TO 10,000 FT.  DIFFERENTIAL PRESSURE STAYED AT 7.2, NO CHANGE IN ALTN MODE.  BEGAN DESCENT AND CABIN PRESSURE DECREASED TO NORMAL RANGE.  OUTFLOW VALVE SHOWED CLOSED ENTIRE SEQUENCE. REMOVED AND REPLACED CABIN PRESSURIZATION OUTFLOW VALVE (AFT) PER M/M, OPS CHECKS GOOD PER MM.

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