NTSB

The loss of engine power for reasons that could not be determined because postaccident engine examination and testing revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation.

Fuel starvation to the left engine and the resulting loss of engine power to that engine, and a loss of airplane control due to the pilot’s failure to maintain the minimum controllable airspeed.

The pilot’s receiving instruction’s failure to maintain directional control during the landing roll, which resulted in impact with trees and a house.

The pilot’s and flight instructor’s failure to verify that the landing gear were extended, which resulted in a gear-up landing. Contributing to the accident was the flight instructor’s inadvertent pulling of the landing gear motor circuit, which prevented the landing gear from extending.

The noninstrument-rated pilot’s improper decision to continue flight into convective weather conditions, which resulted in the airplane exceeding its maximum maneuvering speed and the subsequent in-flight breakup. Contributing to the accident was the pilot’s inadequate preflight weather planning and his inadequate inflight weather avoidance of that weather.

The pilot’s failure to maintain lateral control during landing, which resulted in the left ski impacting snow and a subsequent bounce and loss of directional control.

An in-flight collision with a bird during the approach, which resulted in damage to the vertical stabilizer.

The pilot’s failure to conduct the engine starting procedures in accordance with the Pilot’s Operating Handbook, which resulted in an engine fire.

The student pilot’s failure to maintain directional control during landing, which resulted in a runway excursion and collision with a drainage culvert.