Colorado Aviation Accidents & Incidents

On November 24, 1999, at 1230 mountain standard time, a Bell 206 L-3 helicopter, N617DE, owned by the Department of Energy and operated by Western Area Power Administration, sustained substantial damage during an emergency landing approximately 8 miles south of Rifle, Colorado. The airline transport certificated pilot and sole occupant was not injured. Visual meteorological conditions prevailed for this public use positioning flight operating under Title 14 CFR Part 91 and a company VFR flight plan was on file.

The flight departed Montrose, Colorado, at approximately 1200 on a positioning flight to Craig, Colorado. While in cruise flight at 12,000 feet above mean sea level (MSL), a partial loss of engine power occurred, which necessitated an autorotation to landing in rough terrain approximately 2 miles from the Rifle airport.

According to the pilot, his first indication of a problem was a yaw to the right and the illumination of the engine chip light on the annunciator panel. He said he entered autorotation, made a "mayday" call and assessed the situation. In progressing through the emergency evaluation, the pilot determined that he had complete control and had some power, which he utilized to pass over mountainous terrain that was beneath the helicopter's flight path. When smoke emanating from the engine compartment appeared in the rear view mirror, the pilot secured the engine and did a full autorotative landing to a field.

Although overgrown with vegetation, the field had been plowed at some point in the past and contained a furrowed surface. The helicopter landed perpendicular to the furrows and slid forward about one skid length. Due to the terrain surface, the lower wire cutter dug in resulting in a forward rocking movement of the helicopter. The skid support cross tubes buckled aft, and as the helicopter settled, a main rotor blade flexed downward and contacted the left winglet of the horizontal stabilizer resulting in damage to the winglet and buckling of the tail boom just aft of the fuselage attach point.

External examination of the engine, an Allison 250-C30P, serial number CAE 890136, provided evidence of a catastrophic internal failure. After the helicopter was recovered, the engine was removed and, along with the engine records, was shipped to the Rolls Royce Allison factory in Indianapolis, Indiana, for detailed internal examination. Present at the examination were the NTSB Investigator-In-Charge, and representatives from the Department of Energy, Allison Engines, and Dallas Airmotive.

A review of the engine records provided information that the engine was a rental from Dallas Airmotive. It was a temporary installation due to the original engine being at Dallas Airmotive for a 2,000-hour overhaul.

The initial inspection focused on the oil line from the accessory gearbox since examination provided evidence that this line had oil dripping from its lowest point and the oil tank was empty. Both main oil lines were