Incident Overview
A helicopter engaged in an external load operation in mountainous terrain descended uncontrollably into trees while hovering out of ground effect. The pilot reported maintaining a stabilized hover at 500 feet above ground level (AGL) when the aircraft unexpectedly entered a violent vertical descent. The pilot attempted to jettison the external load but was unable to do so before the helicopter collided with trees.
Post-Accident Examination
Following the accident, a detailed examination of the helicopter's engine revealed no mechanical failures or malfunctions. The engine appeared to have been operating normally prior to the event, with no indications of pre-impact defects.
Operational Context
The flight was conducting an external load operation in mountainous terrain, which often presents challenging aerodynamic conditions. Hovering out of ground effect requires additional power and stability, and the sudden loss of control suggests an aerodynamic or environmental factor, though the source does not specify further details.
Summary
The accident involved a controlled hover that transitioned into an uncontrolled descent, resulting in collision with trees. The inability to jettison the external load may have contributed to the severity of the impact. No mechanical reasons for the descent were found.