# SDR ASAA2022102740516

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 27, 2022
- Submitted: October 31, 2022
- Operation: Air carrier
- Aircraft: [N457AS](https://openairdocs.org/aircraft/N457AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 36355
- Aircraft time: 31,896 hours, 10,123 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Controller
- Part number: 510901601
- Part serial: 5109016001662
- Condition: Malfunctioned
- Location: Cabin Temp
- Stage of operation: NR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2022102740516

## Discrepancy

CONT CABIN TEMP CONTROLLER IS UNCONTROLLABLE, WILL NOT HOLD TEMP. CONTINUALLY SPIKES IN EITHER DIRECTION. WILL HOLD 22C IN OFF POSITION. GROUNDED - YES.  PERFORMED A DUCT TEMPERATURE LIMIT SENSOR TEST REF B737-900 AMM 21-61-04. NO DISCREPANCIES NOTED. RANG OUT S2 (CONT CABIN TEMP SELECTOR) OF THE P5-17 FOR DEAD SPOTS IN THE POT. REF B737-900 WDM 21-61-12 AND 21-61-11. NO DEFECTS NOTED. T/S ON 10-18-22 NOTED THE CONTROL CABIN TCV FAULTING ON A PZTC BITE. REPLACED V143 PER AMM 21-61-21. NO HELP. REPLACED THE #1 PZTC PER AMM 21-61-20. ALL TESTS NORMAL. CONTROL CABIN TEMP CONTROL NOW WORKS NORMALLY. ETOPS GROUND VERIFICATION GOOD.

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