On August 19, 1994, a DE Havilland DHC-2 (registration N1785R) operated by Willow Air Service was involved in an aviation accident near Skwenta, AK. Investigators recorded the probable cause as: The pilot's failure to maintain clearance from a tree stump while moving the float-equipped airplane from a sand bar onto the river. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.
A float-equipped aircraft sustained structural damage to its right horizontal stabilizer and fuselage after striking a tree stump while attempting to depart a sand bar on a river.
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.
Probable cause
The pilot's failure to maintain clearance from a tree stump while moving the float-equipped airplane from a sand bar onto the river.