# SDR UPS99229608

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 14, 1999
- Submitted: March 26, 2000
- Operation: Air carrier
- Aircraft: [N925UP](https://openairdocs.org/aircraft/N925UP), registered now
- Make and model: Boeing 727-31C
- Registry model: [Boeing 727-31C](https://openairdocs.org/model/boeing-727-31c) (OpenAirDocs)
- Aircraft serial: 19230
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Out Flow Valve
- Condition: Stuck
- Location: Right
- Stage of operation: IN
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UPS99229608

## Discrepancy

INSPECTION TYPE:SI, AIR TURNBACK AT 1945UTC DUE TO UNSATISFACTORY AIRCRAFT PRESSURIZATION.  WHEN CLIMB THRUST SET, CARGO HEAT O'FLOW VALVE CLOSED, FULL MANUAL INCRASE ON MANUAL CONTROLLER.  AIRCRAFT WAS ONLY ABLE TO MAINTAIN A CABIN ALTITUDE OF 8,000 AND DIFFERENTIAL OF 7 PSID.  HAD FLIGHT CONTINUED, CABIN ALTITUDE WOULD HAVE EXCEEDED 10,000 2-3MTS.  TROUBLESHOT SYSTEM PER MM, FOUND RT OUTFLOW VALVE TO BE STUCK OPEN DUE TO INSULATION BLANKET STUCK IN VALVE.  REMOVED BLANKET AND PERFORMED PRESSURE CONTROL SYSTEM TEST PER MM 21-30-01.  NO DEFECTS NOTED.

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