# SDR UIEA200800281

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 3, 2008
- Submitted: August 7, 2008
- Operation: Air carrier
- Aircraft: [N528MC](https://openairdocs.org/aircraft/N528MC), registered now
- Make and model: Boeing 747-2D7B
- Registry model: [Boeing 747-2D7B](https://openairdocs.org/model/boeing-747-2d7b) (OpenAirDocs)
- Aircraft serial: 22472
- System (JASC): [3610 · Pneumatic Distribution System](https://openairdocs.org/jasc/3610)
- Part: Relief Valve
- Part number: 227565112
- Condition: Leaking
- Location: Nr 4 Engine
- Stage of operation: CR
- How discovered: O
- Nature of condition: M, J
- Precautionary procedure: E, A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA200800281

## Discrepancy

AT CRUISE NR 4 ENG HAD MULTPLE FIRE WARNINGS ON BOTH A&B.  PERFORMED IN FLIGHT SHUT DOWN AND AIR TURNBACK.  MAINTENANCE FOUND LEAKING PRESSURE RELIEF VALVE, WHICH WAS BLASTING HOT AIR ON THE DETECTORS.  REPLACED OVER PRESSURE RELIEF VALVE PER 36-11-03, OPS CHECKED OK.  (S)

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