# SDR NI6R202606190066

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 18, 2026
- Submitted: June 20, 2026
- Operation: General aviation
- Filed by: [Neptune Aviation Services Inc, repair station NI6R011N](https://openairdocs.org/faa-repair-station/NI6R011N/neptune-aviation-services-inc.md) (OpenAirDocs)
- Aircraft: [N840TW](https://openairdocs.org/aircraft/N840TW), registered now
- Make and model: Gulstm 690C
- Aircraft serial: 11689
- Aircraft time: 13,872 hours, 9,391 cycles
- Engine: Garrtt TPE3315
- System (JASC): [2100 · Air Conditioning System](https://openairdocs.org/jasc/2100)
- Part: Regulator Valve
- Part number: 729182B
- Part serial: 0414
- Condition: Stuck
- Location: Rt Engine
- Part time: 13,594 hours, 9,391 cycles
- Stage of operation: FF
- How discovered: O
- Nature of condition: B
- Precautionary procedure: H, I, A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/NI6R202606190066

## Discrepancy

DURING FLT, SMOKE IN CABIN, DURING SLOW CRUISE FLT OVER FIRE TRAFFIC AREA, PERFORMED QRH ITEMS, REMOVED SMOKE FROM CABIN. DEPARTED THE FTA TO KCDC LANDED WITHOUT FURTHER PROBLEMS. MX TROUBLESHOT SMOKE IN CABIN TO BE COMING FROM RT ENG.  AFTER EXTENSIVE TROUBLESHOOTING OF R/H ENGINE AND AIR CONDITIONING SYSTEM AND COMPONENTS. FOUND REGULATING VALVE NEXT TO ENVIRONMENTAL CONTROL UNIT (ECU) STUCK IN OPEN POSITION. THIS CONDITION ALLOWED FOR UNRESTRICTED P3 AIR TO OVERHEAT ECU AND BURN OFF OIL CAUSING SMOKE AND HIGH DUCT TEMPS.

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