# SDR UALA2012092705468

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 27, 2012
- Submitted: September 28, 2012
- Operation: Air carrier
- Aircraft: [N775UA](https://openairdocs.org/aircraft/N775UA), registered now
- Make and model: Boeing 777222
- Aircraft serial: 26947
- Aircraft time: 70,246 hours, 12,471 cycles
- Engine: Pwa PW4077
- System (JASC): [2131 · Cabin Pressure Controller](https://openairdocs.org/jasc/2131)
- Part: Controller
- Part number: 11511007
- Part serial: 37
- Condition: Malfunctioned
- Location: Ac Bay
- Stage of operation: CL
- How discovered: O
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UALA2012092705468

## Discrepancy

LEFT PACK FAILURE, RTFL.  NOTICED WHEN DOING LEAK CHECK ON UPPER FCV THAT THE LOWER FCV WAS FLUCTUATING OR SURGING.  REPLACE THE AIR SUPPLY CABIN PRESSURE CONTROLLER PCN 566-9019 FOR LEFT PACK FLOW CONTROL VALVE NOT BEING ABLE TO BE SHUTOFF.  REPLACED ASCPC PER AMM, OPS CHECK GOOD AT THIS TIME.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.