Accident Overview
The aircraft struck an embankment approximately 2 miles from the airport and about 200 feet below the airport elevation during a takeoff attempt in icing conditions. Examination of ground scars and wreckage revealed that the airplane hit the berm in near wings-level controlled flight while on a slightly nose-high descending flight path. Both engines were developing symmetrical high power at impact.
Flight Details
The aircraft was transporting cargo and medical specimens along a route flown daily by the pilot according to a company schedule. It had arrived at 1826 from the previous stop. After landing, the pilot requested deicing. A line service technician applied roughly 5 gallons of a 50/50 glycol mix at 1855, one hour before the accident, while the pilot observed. The technician noted a considerable ice buildup from the landing, removing ice and snow from the leading edges, spinners, and fuselage top. Light snow continued during the procedure.
Takeoff and Witness Accounts
Witnesses at the airport who watched the takeoff reported that one or both engines sounded "very rough." The airplane departed runway 21, made a shallow left turn, and disappeared into low clouds. One witness stated the airplane rotated approximately 5,000 feet down the nearly 7,000-foot runway.
Weather and Icing Conditions
The accident airplane was not certified or equipped for flight into known icing conditions. Weather data indicated IFR conditions, light snow showers, and conditions highly conducive to icing from the surface to 20,000 feet at the airport during the aircraft's landing, ground stay, and departure. There was a 95 percent probability of moderate clear to mixed icing from the surface to 10,800 feet. The pilot was aware of the icing conditions at the airport and locally, having received multiple weather briefings that clearly described forecasted and observed icing.
Pilot Context
According to entries in a journal kept by the pilot, there is evidence that the pilot perceived a great deal of pressure to fly in icing conditions with an under-equipped aircraft, with some pressure involving a perceived link between doing so and maintaining employment. However, insufficient information was available to determine whether company culture condoned or encouraged this behavior. It was not determined why the pilot chose to depart in icing conditions. The operator reported that a truck was available to take the cargo to the final destination if weather or mechanical issues prevented the flight.
Investigation Findings
Fatigue was not a factor in the accident. No preimpact mechanical malfunctions or failures were identified during wreckage examinations. The investigation did not establish a probable cause.