# SDR ASAA2021080235582

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 30, 2021
- Submitted: August 3, 2021
- Operation: Air carrier
- Aircraft: [N566AS](https://openairdocs.org/aircraft/N566AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35182
- Aircraft time: 53,887 hours, 15,895 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Modulating Valve
- Part number: 3989083
- Part serial: 19088
- Condition: Faulted
- Location: Lt A/C Pack
- Part time: 30,432 hours, 9,712 cycles
- Stage of operation: NR
- 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/ASAA2021080235582

## Discrepancy

PER SEAMC PAT AND VERBAL FROM FLIGHT CREW CONTROL CABIN ZONE TEMP LIGHT ILLUMINATED AND RESET WITH MASTER CAUTION. GROUNDED - YES. PERFORMED PACK TEMPERATURE CONTROL BITE TEST PER B737-800 FIM 21-62 TASK 801. FOUND FLT DECK TRIM VALVE FAULT ON R/H PACK/ZONE TEMPERATURE CONTROLLER. TROUBLESHOT FAULT PER FIM 21-62 TASK 832. REMOVED AND REPLACED FLT DECK TRIM VALVE ASSY WITH A SERVICEABLE UNIT PER B737-800 AMM 21-61-21. OPS CHECK AND LEAK CHECK GOOD. ETOPS GROUND VERIFICATION SUCCESSFUL.

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