# SDR DXTA2011022804480

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 25, 2011
- Submitted: February 28, 2011
- Operation: Air carrier
- Aircraft: [N817QS](https://openairdocs.org/aircraft/N817QS), registered now
- Make and model: Raythn HAWKER800XP
- Aircraft serial: 258517
- Aircraft time: 7,130 hours, 5,081 cycles
- System (JASC): [2130 · Cabin Pressure Control System](https://openairdocs.org/jasc/2130)
- Part: Check Valve
- Part number: 1301561
- Part serial: 402542
- Condition: Failed
- Location: Cabin Pressure
- Part time: 7,130 hours, 5,081 cycles
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: B, G, A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/DXTA2011022804480

## Discrepancy

ACFT FAILED TO PRESSURIZE EVENLY; ALT WARNING HORN SOUNDED AND MASKED FELL AS WE CLIMBED THOUGH FL200. AFTER EMERGENCY DESCENT, APU WAS REENGAGED BUT EVEN THEN ALT WARNING HORN STAYED ON UNTIL BELOW 8000FT; AND BOTH CREW CONFIRMED ONGOING PRESSURE FLUCTUATIONS.   R & R UPPER AND LOWER CABIN PRESSURE CHECK VALVES IAW MM 21-30-00.  PERFORMED GROUND PRESSURIZATION CHECKS.  OPS CHECKED GOOD.

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