# SDR ASAA2019100192864

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 29, 2019
- Submitted: October 1, 2019
- Operation: Air carrier
- Aircraft: [N461AS](https://openairdocs.org/aircraft/N461AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 36363
- Aircraft time: 21,776 hours, 7,043 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Warning Light
- Condition: False Activation
- Location: Cockpit Temp
- Stage of operation: NR
- How discovered: O
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2019100192864

## Discrepancy

CONT CAB ZONE TEMP LIGHT ILLUMINATED ON MASTER CAUTION RECALL. MASTER CAUTION RESET EXTINGUISHED ZONE TEMP AND AIRCOND ANNUNCIATOR. GROUNDED - YES. RELEASED PER MEL 21-21G FLIGHT DECK PRIMARY TEMP CONTROL INOP. #2 ZTC SHOWED FLT DECK TRIM VALVE FAULT. PERFORMED BITE VERIFY ON BOTH ZTC CONTROLLERS, NO FAULTS NOTED. FAULT RESET REF B737-900 FIM 21-62 TASK 842. THIS CLEARS MEL 21-21G.

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