# SDR ASAA2020122533771

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 25, 2020
- Submitted: December 29, 2020
- Operation: Air carrier
- Aircraft: [N431AS](https://openairdocs.org/aircraft/N431AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 43255
- Aircraft time: 27,205 hours, 8,774 cycles
- System (JASC): [2150 · Cabin Cooling System](https://openairdocs.org/jasc/2150)
- Part: Control Valve
- Part number: 3989085
- Condition: Inoperative
- Location: Lt A/C Pack
- Stage of operation: TX
- How discovered: 9
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2020122533771

## Discrepancy

LEFT PACK LIGHT ILLUMINATED DURING MASTER CAUTION RECALL (AFTER START CHECKLIST).  GROUNDED-YES.  REMOVED AND REPLACED LEFT PACK TEMP CONTROL VALVE, IAW B737-900 AMM 21-51-10.  OPERATIONS AND LEAK CHECK GOOD.

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