# SDR UIEA2026101800991

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 18, 2026
- Submitted: October 19, 2026
- Operation: Air carrier
- Aircraft: [N852GT](https://openairdocs.org/aircraft/N852GT), registered now
- Make and model: Boeing 747-87UF
- Registry model: [Boeing 747-87UF](https://openairdocs.org/model/boeing-747-87uf) (OpenAirDocs)
- Aircraft serial: 37571
- Aircraft time: 61,566 hours, 9,147 cycles
- System (JASC): [2133 · Pressure Regulator/Outflow Valve](https://openairdocs.org/jasc/2133)
- Part: Outflow Valve
- Part number: 50E991
- Part serial: 518
- Condition: Faulted
- Location: Zone 100
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: B, A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA2026101800991

## Discrepancy

CRZ FLT FL 380: CABIN ALT WARNING AT 10,800 FT OBSERVED. ELEC QRH C/W. EMERGENCY DESCENT PERFORMED WITH O2 MASKS ON.(<P>REMOVED AND REPLACED LWR FWD CARGO OVERBOARD VALVE PER AMM 21-26-17/401. TEST PASSED. PERFORMED CABIN PRESSURE LEAKAGE TEST PER AMM 05-51-08. LEAK DOWN RATE ACCEPTABLE. NO FURTHER DEFECTS NOTED</P>)

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