# SDR AT9900152

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 26, 1999
- Submitted: March 26, 2000
- Operation: Air carrier
- Aircraft: [N839AT](https://openairdocs.org/aircraft/N839AT), registered now
- Make and model: Doug DC-9-32
- Registry model: [Doug DC-9-32](https://openairdocs.org/model/mcdonnell-douglas-dc-9-32) (OpenAirDocs)
- Aircraft serial: 47089
- System (JASC): [2130 · Cabin Pressure Control System](https://openairdocs.org/jasc/2130)
- Part: Valve
- Part number: 10315411
- Condition: Defective
- Location: Cabin
- Stage of operation: CR
- Nature of condition: O
- Precautionary procedure: G
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AT9900152

## Discrepancy

LOST CABIN PRESSURE, UNABLE TO CONTROL IT MANUALLY.  PASSENGER IN AFT CABIN REPORTED HEARING A POP JUST BEFORE THE MASK DROPPED.  FOUND THE AFT CABIN PRESSURE SAFETY VALVE OFF IT'S SEAT.  REMOVED AND REPLACED SAFETY VALVE PRESSURE IAW MM 21-30, OPS CHECKED GOOD.

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