# SDR P5CA2025040200010

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 2, 2025
- Submitted: April 4, 2025
- Operation: Air carrier
- Aircraft: [N858GT](https://openairdocs.org/aircraft/N858GT), registered now
- Make and model: Boeing 747-87UF
- Registry model: [Boeing 747-87UF](https://openairdocs.org/model/boeing-747-87uf) (OpenAirDocs)
- Aircraft serial: 37569
- Aircraft time: 57,457 hours, 8,953 cycles
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Valve
- Part number: 4203651
- Part serial: 728A
- Condition: Malfunctioned
- Location: Zone 100
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A, I
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/P5CA2025040200010

## Discrepancy

AIR TURNBACK DUE TO LOSS OF CABIN PRESSURE.(<P>R+R SMOKE OVERIDE VALVE PER AMM 21-58-06, OPS CHECK GOOD.</P>)

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