What happened
On December 3im, 2014, at 1710 mountain standard time, a Bell 206L-4, registration N57AW, collided with terrain approximately 7 miles west of Benson, Arizona. The flight was a repositioning mission originating from Glendale, Arizona, and destined for Sierra Vista, Arizona, to provide air support for the Cochise County Sheriff's Office.
The helicopter was undergoing a 100-hour inspection in Glendale immediately prior to departure. The flight was being conducted under 14 CFR Part 91 regulations. During the flight, the pilot maintained communications with Tucson Approach while transiting through Tucson Class C airspace, following Interstate 10.
Flight data monitoring indicated the helicopter was flying at approximately 300 feet above ground level (agl) along the interstate before descending to about 200 feet agl. The final recorded data points showed the aircraft had climbed to over 500 feet agl and drifted south of the interstate before the impact. The collision resulted in 2 fatal injuries, claiming the lives of the commercial pilot and the pilot-rated mechanic. The helicopter was destroyed.
The investigation
The wreckage was found in a 174-foot debris path in flat desert terrain. The aircraft had fragmented into several sections, including the cockpit, cabin, engine, and tail boom. Investigators noted that the ground scars and wreckage distribution were consistent with a collision with terrain during forward flight.
An examination of the engine revealed no mechanical anomalies or malfunctions that would have prevented normal operation. Investigators also reviewed a Garmin StreetPilot portable GPS, which had sustained significant impact damage but provided a track of the flight path.