# SDR IPXA2025071167979

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 11, 2025
- Submitted: July 11, 2025
- Operation: Air carrier
- Aircraft: [N624UP](https://openairdocs.org/aircraft/N624UP), registered now
- Make and model: Boeing 747-8F
- Registry model: [Boeing 747-8F](https://openairdocs.org/model/boeing-747-8f) (OpenAirDocs)
- Aircraft serial: 63784
- Aircraft time: 18,178 hours, 2,715 cycles
- System (JASC): [2140 · Heating System](https://openairdocs.org/jasc/2140)
- Part: Valve
- Part number: 4528A010001
- Part serial: 452801273
- Condition: Faulted
- Location: Zone 200 Temps
- Stage of operation: CR
- 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/IPXA2025071167979

## Discrepancy

AT FL380 UNABLE TO CONTROL UPPER DECK TEMP€™S. THIS WAS APPROX 1.5 HRS INTO FLIGHT AFTER TALKING WITH MX, DISPATCH AND 5ME, DIVERT BACK TO ANC WAS DECIDED. REMOVED AND REPLACED IASC #1. UPDATED AND VERIFIED SOFTWARE AS PER DASH 8 MATRIX REF AMM 36-10-01-470-802 AND 36-10-01-400-801 ALL TEST PASS. NO MESSAGES AND NO EXSITING FAULTS.

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