On March 8, 1997, a Cessna 170A (registration N1364D) was involved in an aviation accident near Willow, AK. Investigators recorded the probable cause as: The pilot's decision to taxi at excessive speed on a frozen lake with flat lighting conditions, which led to the right landing gear striking snow berms and tearing from the fuselage. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A ski-equipped aircraft suffered structural damage to its right main landing gear after striking a snow berm while taxiing at excessive speed on a frozen lake under flat lighting conditions.
What happened
The pilot was operating a ski-equipped airplane on a frozen lake, preparing for departure. During the taxi phase, the pilot acknowledged that he was moving at an excessive speed. The environmental conditions presented significant visual challenges due to flat lighting, which obscured terrain features from view. As a result of these visibility issues, the pilot failed to notice a berm composed of frozen snow ahead.
The right landing gear ski climbed over the first berm and subsequently impacted a second adjacent snow berm. This impact generated sufficient force to tear the right main landing gear assembly completely away from the airplane fuselage. The aircraft sustained significant structural damage as a direct consequence of this collision with the terrain feature.
The investigation
Examination of the accident site revealed that the right main landing gear had been detached from the airframe. The sequence of events indicated that the ski crested one obstacle and struck another, leading to the catastrophic failure of the attachment points for the right gear.
Probable cause
The pilot's decision to taxi at excessive speed on a frozen lake with flat lighting conditions, which led to the right landing gear striking snow berms and tearing from the fuselage.