NTSB Identification: SEA07LA028.
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Accident occurred Saturday, December 09, 2006 in Bountiful, UT
Probable Cause Approval Date: 04/25/2007
Aircraft: Robinson R-22, registration: N611SC
Injuries: 2 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The pilot was taking a passenger on a local sight-seeing flight, and flew up a mountain canyon. As he started up the canyon, he encountered a slight wind gust, but decided to continue up the canyon. Eventually, he encountered gusting variable wind conditions and significant downdrafts. He elected to turn around and fly out of the canyon. As soon as he started to turn, the helicopter encountered a strong downdraft, and it began to sink rapidly. The main rotor rpm began to slow, and the pilot increased power and lowered the collective. Although he was able to fly out of this downdraft, the helicopter entered another strong downdraft, and sank toward terrain with its main rotor rpm decreasing. In order to stop the descent, the pilot raised the collective, but the helicopter continued to sink, and the main rotor rpm again began to decay. By that time, the pilot was very close to the terrain, and decided to land instead of trying to fly further in the presence of the strong downdrafts. Although the pilot was able to successfully touch down in an open area, soon after the skids came in contact with the rough, steeply-sloped terrain, the helicopter rolled onto its side.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's improper decision to fly up a mountain canyon at low level without knowledge of the wind conditions. Factors associated with the accident are gusty winds, downdrafts, and rough/uneven terrain. Full narrative available
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