# SDR USA2002F00075

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 26, 2002
- Operation: Air carrier
- Aircraft: N531AU
- Make and model: Boeing 737-3B7
- Registry model: [Boeing 737-3B7](https://openairdocs.org/model/boeing-737-3b7) (OpenAirDocs)
- Aircraft serial: 24478
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Outflow Valve
- Part number: 7110033
- Condition: Leaking
- Location: Aft Fuselage
- Part time: 43,421 hours
- Stage of operation: CL
- Nature of condition: J
- Precautionary procedure: B, A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USA2002F00075

## Discrepancy

ON CLIMB OUT, ENROUTE, CABIN ALT WARNING HORN SOUNDED.  CREW REPORTED OUTFLOW VALVE WAS FULLY CLOSED IN AUTO, STANDBY, AND MANUAL PRESS MODES BUT THEY WERE NEVER ABLE TO GET CABIN PRESS.  EMER DESCENT WAS ACCOMPLISHED.  FLIGHT LANDED WITHOUT FURTHER INCIDENT.  NO EMER WAS DECLARED.  MAIN FOUND APU BLEED AIR DUCT PRESS SEAL BOOT IN AFT KEEL BEAM DISLODGED.  RESECURED CLAMP AND BOOT.  FOUND CABIN PRESS OUTFLOW VALVE BLADE SEALS LEAKING.  REMOVED AND REPLACED CABIN PRESS OUTFLOW VALVE.  OPS CHECK GOOD.  PRESS A/C TO 6.5 PSI.  NO LEAKS NOTED.  CLEARED MEL ON LEFT PACK BY REPLACING LEFT PACK WATER SEPARATOR 35 DEGREE SENSOR (PN 6275701).  LEFT PACK OUTPUT READS 4 DEGREES CENTIGRADE IN FULL COLD.  A/C OK FOR SERVICE.

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