# SDR CHIA202508149805

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 14, 2025
- Submitted: August 19, 2025
- Operation: Air carrier
- Aircraft: [N246CH](https://openairdocs.org/aircraft/N246CH), registered now
- Make and model: Boeing 234
- Registry model: [Boeing 234](https://openairdocs.org/model/boeing-vertol-234) (OpenAirDocs)
- Aircraft serial: MJ017
- Aircraft time: 22,404 hours
- System (JASC): [6320 · Main Rotor Gearbox](https://openairdocs.org/jasc/6320)
- Part: Transmission
- Part number: 234D62006
- Part serial: A113582
- Condition: Overheated
- Location: Nr 2
- Part time: 8,174 hours
- Stage of operation: CL
- How discovered: O
- Nature of condition: M, J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CHIA202508149805

## Discrepancy

THE NR 2 ENGINE TRANSMISSION TEMPERATURE EXCEEDED UPPER TEMPERATURE LIMIT IN FLIGHT RESULTING IN PILOTS INITIATING ENGINE XMSN HOT EMERGENCY PROCEDURES AND RETURNING TO BASE FOR AN UNSCHEDULED LANDING.  REMOVED THE NR 2 ENGINE TRANSMISSION ASSEMBLY AS UNSERVICEABLE IAW NEVER EXCEED TEMP LIMITS OF 234-2 MM AND REPLACED WITH A SERVICEABLE ASSEMBLY. DEFINITIVE CAUSE UNKNOWN AT THIS TIME PENDING COMPONENT DISASSEMBLY AND INSPECTION.  AIRCRAFT WAS RETURNED TO SERVICE.

---
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.