Primary finding
Probable cause
The pilot's decision to depart from an unsuitable, off-airport site, which resulted in a collision with a tree.
Investigator assessment
Analysis narrative
The pilot reported that prior to departing in a ski-equipped airplane, from a remote frozen, snow covered lake; he prepared the off-airport site by packing down the loose snow. During his takeoff roll, the left ski slid off the prepared surface, and encountered loose snow and water overflow which pulled the airplane hard to the left. The left wing struck a tree, substantially damaging the left wing. The pilot stated that there were no preaccident mechanical anomalies that would have precluded normal operation. In the recommendation section of the NTSB Accident/Incident Reporting Form 6120.1, the pilot stated that the accident may have been avoided if he had prepared a wider takeoff area.
Source record
Factual narrative
The pilot reported that prior to departing in a ski-equipped airplane, from a remote frozen, snow covered lake; he prepared the off-airport site by packing down the loose snow. During his takeoff roll, the left ski slid off the prepared surface, and encountered loose snow and water overflow which pulled the airplane hard to the left. The left wing struck a tree, substantially damaging the left wing. The pilot stated that there were no preaccident mechanical anomalies that would have precluded normal operation.