# SDR DXTA2011061504617

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 15, 2011
- Submitted: March 9, 2012
- Operation: Air carrier
- Aircraft: [N671QS](https://openairdocs.org/aircraft/N671QS), registered now
- Make and model: Cessna 560XL
- Registry model: [Cessna 560XL](https://openairdocs.org/model/cessna-560xl) (OpenAirDocs)
- Aircraft serial: 5605071
- Aircraft time: 9,380 hours, 7,409 cycles
- System (JASC): [2140 · Heating System](https://openairdocs.org/jasc/2140)
- Part: Control Valve
- Part number: 2724128714
- Part serial: 10ARH221
- Condition: Malfunctioned
- Location: Cabin Heat
- Part time: 9,380 hours, 7,409 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: M, B
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/DXTA2011061504617

## Discrepancy

AIR DUCT OVER HEAT CABIN (ENVIRONMENTAL DUCT OVERTEMP) REACHED A TEMP OF 325C AND WAS INCREASING AND SMOKE IN THE CABIN IN-FLIGHT.  FOLLOWED CHECKLIST Q4 AND TEMP DECREASED TO 208C.  TROUBLESHOT "AIR DUCT O' HEAT CABIN" LIGHT, CABIN SUPPLY AIR UNCONTROLLABLE IN MANUAL MODE, FOUND TEMP CONTROL VALVE FOILED, R & R CABIN TEMP CONTROL VALVE WITH AN O/H UNIT IAW MM CH 21-31-00.  OPS CHECKED GOOD.

---
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.