What happened
The flight was conducted at very low altitude over rugged, forested mountainous terrain. During this phase of the operation, the aircraft encountered a significant downdraft that induced a sudden and rapid loss of altitude. The pilot attempted to execute corrective maneuvers to arrest the descent; however, the available time and altitude were insufficient for recovery.
Before effective control could be re-established, one of the aircraft's wings struck a tree. The impact caused the aircraft to lose structural integrity and cartwheel into the ground. Upon coming to rest, a fire broke out within the wreckage. This fire consumed approximately 50 percent of the aircraft structure.
The investigation
Examination of the accident site revealed that the initial point of contact was a tree, which caused the wing failure. The subsequent motion of the aircraft was consistent with a cartwheeling impact pattern against the terrain. Post-impact fire damage was extensive but limited to roughly half of the total airframe.
Findings
The primary factor in this accident was the encounter with a downdraft while flying at low altitude over complex terrain. The pilot's inability to recover from the sudden sink rate prior to impacting an obstacle led to the loss of control and subsequent collision with terrain.
Safety message
Flying at very low altitudes over mountainous areas presents significant risks due to unpredictable weather phenomena such as downdrafts. Pilots must maintain adequate altitude to allow for recovery time in case of sudden changes in air movement or unexpected obstacles.