Preflight and Weather Conditions
The pilot reported that during preflight, it was snowing and he wiped snow that had accumulated on the wings "as best as [he] could". While taxiing, snow was falling heavily and he observed "light accumulation of wet snow" on the wings. Recorded data from the automated weather observation station, located on the airport, indicated that about 27 minutes before the accident, the wind was 010° at 8 knots, visibility ½ mile, moderate snow, freezing fog, sky condition broken at 500 ft agl and overcast at 1,500 ft agl. The airplane departed runway 16.
Takeoff and Climb
During the takeoff roll, the pilot observed snow "sloughing off" the wings as airspeed increased. During the climb about 150 ft above ground level, the airplane yawed to the left. The pilot attempted to recover using right aileron. He reported that he "could see a stall forming", so he lowered the nose and reduced power to idle.
Impact and Damage
The airplane impacted the general aviation ramp in a left wing down attitude and slid 500 to 600 ft. The airplane sustained substantial damage to the fuselage and left wing.
Pilot Report and Recommendations
On the NTSB Aircraft Accident/Incident Report form, the pilot reported that the airplane stalled and recommended "better deicing" before takeoff. The pilot also stated that there were no preaccident mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
Regulatory Guidance
The Federal Aviation Administration Aeronautical Information Manual (AIM) states: "The presence of aircraft airframe icing during takeoff, typically caused by improper or no deicing of the aircraft being accomplished prior to flight has contributed to many recent accidents in turbine aircraft." The manual further emphasizes that lift-generating surfaces must be completely free of contamination before flight, and a tactile check should be performed when feasible.
The Federal Aviation Administration Advisory Circular AC 135-17 notes that test data indicate ice, snow, or frost formations with thickness and surface roughness similar to medium or coarse sandpaper on the leading edge and upper surfaces of a wing can reduce wing lift by as much as 30 percent and increase drag by 40 percent.
A service bulletin from the airplane manufacturer, included in the public docket, describes de-icing and anti-icing ground procedures. It states that during conditions conducive to aeroplane icing during ground operations, takeoff shall not be attempted when ice, snow, slush or frost is present on wings, propellers, control surfaces, engine inlets or other critical surfaces. It references the "Clean Aircraft Concept" and notes that any deposit of ice, snow or frost may drastically affect performance due to reduced aerodynamic lift and increased drag.