# SDR 2009F00121

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 25, 2009
- Submitted: November 25, 2009
- Operation: General aviation
- Aircraft: [N935QS](https://openairdocs.org/aircraft/N935QS), registered now
- Make and model: Cessna 750
- Registry model: [Cessna 750](https://openairdocs.org/model/cessna-750) (OpenAirDocs)
- Aircraft serial: 7500135
- Aircraft time: 8,633 hours, 5,328 cycles
- System (JASC): [2130 · Cabin Pressure Control System](https://openairdocs.org/jasc/2130)
- Part: Cabin Pressure
- Condition: Malfunctioned
- Stage of operation: DE
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2009F00121

## Discrepancy

PULLING THE POWER TO IDLE DESCENDING FROM 10000' WE HEARD A LOUD POP AND THE CABIN PRESSURE DUMPED.  CABIN DIFFERENTIAL REMAINED AT ZERO AND THE CABIN RATE OF CHANGE FOLLOWED WHATEVER THE PLANE WAS DOING.  OCCASIONALLY THE RATE WOULD FLUCTUATE +- 200' WITH CHANGE OF POWER SETTING BUT WOULD RETURN TO THE RATE AT WHICH THE ACFT WAS DESCENDING.

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