# SDR ASAA2021011733882

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 17, 2021
- Submitted: January 20, 2021
- Operation: Air carrier
- Aircraft: [N519AS](https://openairdocs.org/aircraft/N519AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 36482
- Aircraft time: 43,878 hours, 12,966 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Modulating Valve
- Part number: 3989085
- Part serial: 9101
- Condition: Inoperative
- Location: Lt A/C Pack
- Part time: 49,788 hours, 15,319 cycles
- 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/ASAA2021011733882

## Discrepancy

ON MASTER RECALL AFTER START CHECKLIST CONT CABIN ZONE TEMP LIGHT ILLUMINATED AND RESET AFTER MASTER CAUTION RESET.  GROUNDED-YES.  REMOVED AND REPLACED CONT CABIN ZONE TRIM VALVE, IAW B737-800 AMM 21-61-21.  OPERATIONS AND LEAK CHECK GOOD.

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