NTSB Identification: SEA02TA110
14 CFR Public Use
Accident occurred Tuesday, June 25, 2002 in Rainier, WA
Probable Cause Approval Date: 05/13/2003
Aircraft: Bell 206B, registration: N1087L
Injuries: 3 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this public aircraft accident report.
The pilot reported that he was dispatched to Mount Rainier to provide air support for a rescue mission of an injured hiker. Load calculations prepared by the pilot indicated that the helicopter would be operating at the high end of its performance capabilities. The pilot also reported that this was his first time operating on Mount Rainier. After a briefing, the pilot took one climbing guide from one helibase, and then picked up a climbing ranger from another location before proceeding to the site where the injured hiker was located at about the 10,000 to 10,400 foot level. Since the pilot was unfamiliar with the mountain, the guide and ranger also provided assistance to the pilot in where to go. The pilot was to drop off the guide and ranger at about the 9,000 foot level. After flying over the site to survey the ground conditions on the glacier which consisted of 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 feet and 9,000 feet. The pilot then chose a location in which he positioned the helicopter nose into the slightly rising terrain. The climbing ranger stated that the landing skid from the aft cross tube forward was on the ground. The terrain from the aft cross tube back sloped down about 5 degrees. After the pilot set the helicopter down slowly on the ground, he used the pedals to test for compaction. The pilot stated that as he was lowering the collective, the helicopter suddenly pitched and he applied forward cyclic and lifted off the ground. The helicopter began to rotate clockwise. The pilot applied left pedal input which did not have any effect. The pilot realized that he had no tail rotor control and lowered the collective and impacted on the glacier with the nose pointing downhill. Both occupants on board the helicopter and one witness located about 500 feet above the accident site reported that after the helicopter set down, it appeared to them that the helicopter slid backwards which lowered the tail and raised the nose of the helicopter. The witness above the accident site stated that he thought that the pilot would have landed perpendicular to the terrain slope so that the skids would not act like skis when weighted and slide downhill. Prior to recovery of the helicopter from the glacier, it was lost in a crevasse and covered by snow and rock fall. The load calculation prepared by the pilot was reviewed after the accident. It was 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.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to maintain aircraft control while trying to land. Rough/uneven terrain, inaccurate performance data calculations, inadequate in-flight planning and lack of familiarity with the geographic area were factors. Full narrative available
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