# SDR ASAA2019020428031

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 4, 2019
- Submitted: February 6, 2019
- Operation: Air carrier
- Aircraft: [N474AS](https://openairdocs.org/aircraft/N474AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 40715
- Aircraft time: 14,324 hours, 4,732 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Filter
- Condition: Dirty
- Location: Cabin Temp
- 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/ASAA2019020428031

## Discrepancy

ON MASTER CAUTION RECALL AFTER START AIR COND. ZONE TEMP CONT CAB, ILLUMINATED. FOLLOWED QRH VERIFIED VALVE WORKED W/ PROCEDURE. GROUNDED - YES. RELEASED PER MEL 21-21G FLIGHT DECK PRIMARY TEMP CONT INOP. CLEANED CONT CABIN TEMP SENSOR FILTER. ACCOMP ZONE TEMP CONT BITE. NR 1 SHOWS NO FAULTS. NR 2 SHOWS TRIM VALVE (V143) FLT DECK FAULT. CLEARED FAULT RERAN BITE TEST, TEST PASS NO FAULTS NOW ON NR 2 CONTLR. A/C RELEASED PER MEL 21-21G REMOVED. REF FIM 21-62 TASK 801 & AMM 21-61-06-400-801.

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