# SDR ASAA2020120133625

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 1, 2020
- Submitted: December 4, 2020
- Operation: Air carrier
- Aircraft: [N478AS](https://openairdocs.org/aircraft/N478AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 44105
- Aircraft time: 20,467 hours, 6,591 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Valve
- Condition: Faulted
- Location: Cockpit Temp
- Stage of operation: TX
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2020120133625

## Discrepancy

AFTER PUSHBACK/ENGINE START CONT CAB ZONE TEMP LIGHT ILLUMINATED ON RECALL, EXTINGUISHED UPON MASTER CAUTION RESET.  GROUNDED-YES.  VERIFIED DISCREPANCY, PERFORMED BOTH TPC BITE B737-900 FIM 21-62 TASK 801.  FOUND ON NR 2 PZTC FLT DECK TRIM VALVE FAULT.  ABLE TO CLEAR FAULT.  PERFORMED FIM TASK 21-62-00-810-842.  GROUND RAN BOTH PACKS FOR 1 HR.  NO FAULTS RETURNED.

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