# SDR ASAA2021100836221

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 8, 2021
- Submitted: October 12, 2021
- Operation: Air carrier
- Aircraft: [N431AS](https://openairdocs.org/aircraft/N431AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 43255
- Aircraft time: 29,476 hours, 9,473 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Unknown
- Part number: UNKNOWN
- Condition: Unknown
- Location: Unknown
- Stage of operation: NR
- How discovered: V
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021100836221

## Discrepancy

FLT DECK TEMP CONTROL ZONE TEMP LIGHT ILLUMINATES ON MASTER CAUTION RECALL. EXTINGUISHES WITH M.C. RESET. GROUNDED - YES. VERIFIED CONTROL CABIN ZONE TEMP ILLUMINATES ON RECALL. PERFORMED PZTC BITE, PZTC #2 FAULTED CONTROL CABIN TRIM VALVE ON BIT AND PREV FLIGHT, RESET ON VERIFY. CONFIRMED CONTROL CABIN TRIM VALVE OPERATES NORMALLY ON SUBSEQUENT PZTC TESTS. ETOPS GROUND VERIFICATION SUCCESSFUL.

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