# SDR ASAA2022031037667

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 10, 2022
- Submitted: March 14, 2022
- Operation: Air carrier
- Aircraft: [N587AS](https://openairdocs.org/aircraft/N587AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35684
- Aircraft time: 51,199 hours, 14,897 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Modulating Valve
- Part number: 3989085
- Part serial: 6835
- Condition: Inoperative
- Location: Left Ecs Bay
- Part time: 62,521 hours, 22,479 cycles
- 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/ASAA2022031037667

## Discrepancy

CONTROL CAB ZONE TEMP LIGHT EXTINGUISH ON RECALL. GROUNDED - YES. CONTROLLER BITE HAD HARD FAULT CALLING OUT CONTROL CABIN TRIM MODULATING VALVE. WOULDN'T RESET. REMOVED AND REPLACED CONTROL CABIN MODULATING VALVE IAW B737-800 AMM 21-61-21-000-801 AND AMM 21-61-21-400-801, ETOPS GROUND FUNCTIONAL CHECK OPS CHECK GOOD IAW AMM. 21-61-00-700-806-002.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.