Incident Overview
A helicopter pilot was conducting a hover near a volcano vent when a steam cloud enveloped the aircraft. The pilot lost visual contact with the ground while at a 5-foot hover. In an attempt to regain visual reference, the pilot initiated a descent.
Sequence of Events
During the descent, the helicopter's left skid contacted a rock. This contact caused the helicopter to roll to the right and subsequently strike the ground. The collision with mountainous terrain occurred in the vicinity of the volcano vent.
Contributing Factors
While the source does not explicitly assign a probable cause, the sequence indicates that the steam cloud led to a loss of visual contact, and the subsequent descent resulted in an impact with terrain.