# SDR UALA2008121106842

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 8, 2008
- Submitted: December 12, 2008
- Operation: Air carrier
- Aircraft: [N664UA](https://openairdocs.org/aircraft/N664UA), registered now
- Make and model: Boeing 767322
- Aircraft serial: 29236
- Aircraft time: 36,425 hours, 10,289 cycles
- Engine: Pwa PW4056
- System (JASC): [3610 · Pneumatic Distribution System](https://openairdocs.org/jasc/3610)
- Part: Shutoff Valve
- Part number: 7732887810
- Condition: Faulty
- Location: Lt Engine
- Stage of operation: IN
- How discovered: O
- Nature of condition: W
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UALA2008121106842

## Discrepancy

LEFT ENGINE HIGH STG SYSTEM FLUCTUATES WILDLY FROM 15-40 PSI AT 75-77 PCT N2.  ABOVE 80 PCT N2, PNEU STEADY AT ALL POWER SETTINGS.  REPLACED HI STAGE VALVE AND CONTROLLER.  FAILED TEST AFTER VALVE REPLACEMENT.  ACP'D PNEUMATIC HEALTH CK ON PRV & PRC, HPSOV & HPC, FAMV, AND PRSOV.  PRSOV FAILED HEALTH CK.  REPLACED PRSOV BLEED SHIFT & OPS CHECK PERFORMED, ALL NORMAL.

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