Incident Overview
A helicopter was descending out of mountainous terrain and proceeded over a large mountain lake. The aircraft was cruising at approximately 100 knots at an altitude between 200 and 250 feet above the water, which was described as very clear and perfectly calm.
Sequence of Events
While flying over the lake, the pilot looked inside the cockpit to check the instruments. Upon looking outside and below the helicopter, the pilot experienced a feeling of mental confusion similar to vertigo. The pilot estimated that the helicopter was then between 15 and 20 feet above the water. The pilot pulled aft on the cyclic control, causing the helicopter to impact the water. The aircraft pitched forward and subsequently sank.
Egress and Statements
The pilot and the two passengers were able to egress from the helicopter while it was submerged. Immediately after the accident, the pilot informed a park ranger who was on scene that he was traveling a little low and believed he had set a skid in the water. One of the passengers stated that moments before the collision with the water, the pilot had asked them if they wanted to get closer to the water and if they wanted to chase some birds.