SDR UIEA2025120301333

Service difficulty report · Thermal Switch · Boeing 74745EF

Difficulty date: December 3, 2025
Submitted: December 8, 2025
Operation: Air carrier
Aircraft: N485MC
Make and model: Boeing 74745EF
Aircraft serial: 30607
Aircraft time: 111,839 hours, 19,766 cycles
System (JASC): 3610 · Pneumatic Distribution System
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

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

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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