# SDR ASAA2018021023474

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 10, 2018
- Submitted: February 12, 2018
- Operation: Air carrier
- Aircraft: [N493AS](https://openairdocs.org/aircraft/N493AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 41727
- Aircraft time: 7,092 hours, 2,392 cycles
- System (JASC): [2197 · Air Conditioning System Wiring](https://openairdocs.org/jasc/2197)
- Part: Circuit Breaker
- Condition: Tripped
- Location: Recirc Fan
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2018021023474

## Discrepancy

CONTROL CABIN TEMP CONTROL KNOB DOES NOT SEEM TO HAVE AN EFFECT ON CONTROL CABIN DUCT TEMP WHICH SEEMED STUCK AT 19 - 20 C, THE ENTIRE FLIGHT.  ACFT GROUNDED.  FOUND THE RECIRCIRCULATION FAN CIRCUIT BREAKER P6-4 E4 OPEN ON ARRIVAL.  RESET THE CIRCUIT BREAKER IAW AMM 20-60-01-860-801, NO DEFECTS NOTED AND RECIRCULATION FAN OPERATES NORMALLY.  PERFORMED PACK ZONE TEMP CONTROLLER BITE IAW AMM 21-61-00-700-806-002, NO FAULTS NOTED ON EITHER CONTROLLER.  OPERATED PACK TEMP, AND IT WAS CONTROLLABLE. THE RECIRCULATION FAN OPS TESTED IAW AMM 21-25-00-710-802-002.

---
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.