# SDR USA2002F00033

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 26, 2002
- Operation: Air carrier
- Aircraft: [N423US](https://openairdocs.org/aircraft/N423US), registered now
- Make and model: Boeing 737401
- Aircraft serial: 23990
- System (JASC): [2130 · Cabin Pressure Control System](https://openairdocs.org/jasc/2130)
- Part: Boot
- Condition: Out Of Position
- Location: Duct Seal Boot
- Stage of operation: CR
- Nature of condition: J
- Precautionary procedure: B
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USA2002F00033

## Discrepancy

(DUCT SEAL BOOT)  ENROUTE, THE CABIN ALTITUDE WARNING HORN SOUNDED ALERTING THE CREW THAT CABIN ALTITUDE WAS AT 10,000 FEET.  WITH OUTFLOW VALVE CLOSED, CREW WAS UNABLE TO CONTROL CABIN ALTITUDE.  CREW DESCENDED FLIGHT AND DIVERTED, WHERE THE FLIGHT LANDED WITHOUT FURTHER INCIDENT.  NO EMERGENCY WAS DECLARED AND NO OXYGEN MASKS WERE DEPLOYED.  MAINTENANCE RESECURED DUCT SEAL BOOT IN KEEL BEAM AREA.  LEAK CHECK GOOD.  ALSO, REPLACED FORWARD ENTRY DOOR LOWER HINGE FLAP SEAL.  LEAK CHECK GOOD.  PERFORMED LEAK DOWN RATE TEST PER MM.  OPERATIONAL TEST SATISFACTORY.

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