What happened
A certificated commercial pilot and one passenger were preparing for a non-scheduled Part 135 fishing and guide cross-country flight in a float-equipped aircraft. The operation was taking place in a river area. As the pilot applied engine power to move the airplane from a sand bar onto the river, the right horizontal stabilizer struck a tree stump. This impact resulted in damage to the stabilizer spar and the fuselage.
The investigation
The examination of the aircraft revealed that the right horizontal stabilizer had been damaged by contact with a submerged or partially exposed obstacle. The fuselage also sustained damage from the same event. The damage was consistent with the pilot's account of striking a tree stump during the initial phase of movement.
Findings
The primary factor in this incident was the presence of a tree stump in the waterway at the departure point. The pilot failed to ensure the takeoff path was clear of submerged obstacles, leading to structural damage to the aircraft's empennage and airframe during the low-speed maneuver.