Preflight and Departure
Before departure, an estimated 3–4 inches of snow had accumulated on the aircraft. The pilot reported sweeping snow off except for an area he could not reach. Heavy, wet snowfall continued as the aircraft was prepared for departure, during runup, taxi, and takeoff. The tower advised the pilot that visibility was 1/8 mile with fog and snow; the published takeoff minimum for the FAR 135 operation was 1/2 mile.
The Accident Sequence
After striking a snowplow located 150 feet to the left of the runway, the aircraft continued over an embankment and came to rest inverted. Ice and snow were found on the upper tail surface. The elevator trim was at full nose-down indication, and the aileron trim indicated left bank.
Witness and Pilot Accounts
Witnesses reported that engine sounds were normal and landing lights were on; visibility from the snowplow’s position was approximately 600 feet. The pilot stated that, when descending, manifold pressure indicated 35 inches, and that manifold pressure increased with additional throttle. No engine roughness was reported.
Official Findings
The probable cause was determined to be a loss of control during the takeoff initial climb phase. Contributing factors included: dark night light conditions; fog and snow; the pilot’s inadequate removal of ice and frost from the aircraft; the pilot not obtaining proper assistance; the weather being below approach/landing minimums; the pilot disregarding IFR procedures; snow-covered terrain; and the pilot not maintaining airspeed (Vs). A subsequent in-flight collision with an object (the snowplow) occurred during the same phase of operation.