# SDR P5CA2013042900020

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 27, 2013
- Submitted: April 29, 2013
- Operation: Air carrier
- Aircraft: [N451PA](https://openairdocs.org/aircraft/N451PA), registered now
- Make and model: Boeing 747-46NF
- Registry model: [Boeing 747-46NF](https://openairdocs.org/model/boeing-747-46nf) (OpenAirDocs)
- Aircraft serial: 30809
- Aircraft time: 53,962 hours, 8,888 cycles
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Control Unit
- Part number: 79688540002
- Part serial: 97052067
- Condition: Failed
- Location: Cabin Pressure
- Part time: 54,786 hours, 9,382 cycles
- 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/P5CA2013042900020

## Discrepancy

AIRCRAFT WOULD NOT HOLD PRESSURIZATION.  PERFORMED OUTFLOW VALVE LEFT AND RIGHT QRH ITEMS TO NO AVAIL.  REMOVED AND REPLACED LEFT OUTFLOW VALVE INTERFACE CONTROL UNIT AS PER AMM 21-31-10.  OPERATIONAL CHECK GOOD AS PER AMM 21-31-10.

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