DATE OF INCIDENT:  7/5/2023

DESCRIPTION OF INCIDENT:

The helicopter that this engine was in struck a powerline/pole during an aerial application. Altitude was not sufficient enough for the aircraft to execute a complete autorotation landing. Helicopter impacted corn field and rolled on it's side. This 250 turboshaft engine was originally produced by the Allison Engine Company in the 1960's. The Model 250 has been produced by Rolls-Royce since it acquired Allison in 1995.  An important design  feature of the Model 250 engine is its modular construction which greatly simplifies maintenance and repair activity. Also the unique reverse-flow design provides for ease of hot section maintenance.

There are four modules:

• compressor module, at the front of the engine
• gearbox module (including accessory drives)
• turbine module (including V-shaped exhaust ports)
• combustion module (including twin compressed air transfer ducts) at the rear                                                

Earlier versions have seven axial compressor stages mounted on the HP shaft to supercharge a relatively low-pressure-ratio centrifugal compressor. The -C20B is typical, with an overall pressure ratio of 7.2:1, at an airflow of 3.45 lb/s (1.8 kg/s), with a power output, at the shaft, of 420 hp (310 kW).

ENGINE:       Allison   MODEL:  250-C20J   S/N:  CAE-272642  TT:  12,438.7    TSMOH:  1,758.7

DESCRIPTION OF DAMAGE:

Compressor blades 1st and 2nd stage with minor chipping

Stator Veins

REMARKS:

Times are per logbooks entries.

Engine was installed new in 1993.

This engine was removed from a Bell 206B (N67FA) in late October of 2023 and has been stored inside.

LOCATION OF SALVAGE:   Greeley, CO

SALVAGE MAY BE INSPECTED BY SENDING AN EMAIL:         Salvage@UnderwritersSalvageCompany.com