What happened
The commercial certificated pilot was taxiing a tundra tire-equipped airplane along the edge of a remote river in preparation for takeoff. The gravel area he was using had several tree stumps along the river bank. The pilot said that while taxiing, the right main landing gear tire entered a small, soft, depression. The right wing dipped downward and struck a tree stump, and received damage to the leading edge and the rear spar.
The investigation
The examination of the aircraft revealed damage to the right wing structure. Specifically, the leading edge and the rear spar were compromised after the wing struck a tree stump. The incident occurred because the right main landing gear tire entered a small, soft depression in the gravel taxiway area adjacent to the river bank.
Findings
Contributing factors included the remote location of the takeoff site and the presence of obstacles such as tree stumps along the river bank. The pilot's decision to taxi on an uneven gravel surface with hidden depressions led to the aircraft striking a fixed object.