Incident Overview
A helicopter pilot was dispatched to Mount Rainier to provide air support for a rescue mission of an injured hiker. The pilot's load calculations indicated the helicopter would be operating at the high end of its performance capabilities. This was the pilot's first time operating on the mountain. After a briefing, the pilot picked up a climbing guide from one helibase and a climbing ranger from another location before proceeding to the site where the injured hiker was located at approximately 10,000 to 10,400 feet. The guide and ranger provided navigation assistance due to the pilot's unfamiliarity with the mountain.
Landing Attempt
The pilot was to drop off the guide and ranger at about the 9,000-foot level. After flying over the site to survey ground conditions on the glacier—which included crevasses and uneven ground from avalanche debris—and to check helicopter performance, the pilot attempted to land at several locations on the glacier between about 8,000 and 9,000 feet. He then chose a location where he positioned the helicopter nose into slightly rising terrain. The climbing ranger stated that the landing skid from the aft cross tube forward was on the ground, while the terrain from the aft cross tube back sloped down about 5 degrees.
Sequence of Events
After setting the helicopter down slowly on the ground, the pilot used the pedals to test for compaction. As he was lowering the collective, the helicopter suddenly pitched. The pilot applied forward cyclic and lifted off the ground. The helicopter began to rotate clockwise. The pilot applied left pedal input, which had no effect. Realizing he had no tail rotor control, he lowered the collective and impacted on the glacier with the nose pointing downhill.
Both occupants on board and a witness located about 500 feet above the accident site reported that after the helicopter set down, it appeared to slide backward, which lowered the tail and raised the nose. The witness above the accident site stated that he thought the pilot should have landed perpendicular to the terrain slope so that the skids would not act like skis when weighted and slide downhill.
Aftermath
Prior to recovery of the helicopter from the glacier, it was lost in a crevasse and covered by snow and rock fall. The pilot's load calculation was reviewed after the accident and found that for the actual conditions at the accident site, the helicopter was operating from 60 to 285 pounds over its allowable load for hover out of ground effect performance.