# SDR UIEA2025120301333

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 3, 2025
- Submitted: December 8, 2025
- Operation: Air carrier
- Aircraft: [N485MC](https://openairdocs.org/aircraft/N485MC), registered now
- Make and model: Boeing 747-45EF
- Registry model: [Boeing 747-45EF](https://openairdocs.org/model/boeing-747-45ef) (OpenAirDocs)
- Aircraft serial: 30607
- Aircraft time: 111,839 hours, 19,766 cycles
- System (JASC): [3610 · Pneumatic Distribution System](https://openairdocs.org/jasc/3610)
- Part: Thermal Switch
- Part number: 31002501
- Part serial: NSN
- Condition: Faulted
- Location: Zone 400
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA2025120301333

## Discrepancy

CLIMBING OUT OF 8000FT BLD DUCT LEAK L CAUTION MSG/ BLEED FAMV ENG 4.  REF FIM 36-11 TASK 985 & WDM 26-18-13. T/S & WIRE CHK, FOUND THERMAL SW S907 AT FAULT. R & R THERMAL SWITCH IAW AMM 26-18-02 & IPC 26-18-02-01, ITEM 420.  FIRE TEST RESULT PASSED, APU RUNNING WITH LT & RT BLEED, OK FOR 30 MINUTES, NO MSG NOTED.

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