# SDR UALA2011121506885

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 13, 2011
- Submitted: December 16, 2011
- Operation: Air carrier
- Aircraft: [N776UA](https://openairdocs.org/aircraft/N776UA), registered now
- Make and model: Boeing 777222
- Aircraft serial: 26937
- Aircraft time: 64,696 hours, 11,573 cycles
- Engine: Pwa PW4077
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Shutoff Valve
- Part number: 8102294
- Part serial: 139
- Condition: Faulty
- Location: Ac Bay
- Stage of operation: NR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UALA2011121506885

## Discrepancy

L TRIM AIR VALVE WILL NOT OPEN. TRIM AIR L 1) OVERHEAT IN ZONE SUPPLY DUCT, OR 2) LEFT TRIM PRSOV FAILED CLOSED, OR 3) LEFT TRIM AIR SWITCH COMMANDED OFF.  ADVISORY MSG-2124201 INACTV ER MODE. L TRIM AIR VALVE WILL NOT OPEN.  CABIN TEMP CONTROL REQUIRES SO MUCH ATTENTION THAT IT IS UNSAFE.  REPLACED LEFT TRIM AIR PRSOV AND CKS GOOD.

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