Leadville, CO, USA
N997GM
Bell 206B-III
The pilot, who was on a power line patrol in mountainous terrain, flew the helicopter 100 feet to the right of the power line and into a 10 to 18 knot headwind. Airspeed was between 70 and 80 knots, altitude was 400 feet above the ground, and power was between 70 to 80 percent torque. As he turned to continue following the power line, a "strong downdraft pushed the helicopter" into the ground despite his efforts to regain control. The helicopter struck snow-covered terrain and rolled over.
On April 4, 2002, approximately 1400 mountain standard time, N997GM, a Bell 206B-III helicopter, operated by AeroWest Helicopters, Inc., of Corrales, New Mexico, was destroyed when it struck terrain during an uncontrolled descent 5 miles north of Leadville, Colorado. Both the commercial pilot and a passenger received minor injuries. Visual meteorological conditions prevailed, and no flight plan had been filed for the aerial observation flight being conducted under Title 14 CFR (Code of Federal Regulations) Part 91. The flight originated in Eagle, Colorado, approximately 1330. According to a written statement given to the Lake County Sheriff's Office, the pilot said he was patrolling a power line between Leadville and Breckenridge. He was about 100 feet to the right of the power line, flying east into a 10 to 18 knot headwind. Airspeed was between 70 and 80 knots, altitude was 400 feet above the ground, and power was between 70 to 80 percent torque. The power line turned north towards Mosquito Pass. As the pilot started the turn, a "strong downdraft pushed the helicopter" towards the ground. The LOW ROTOR RPM horn sounded and the pilot lowered the collective control to regain rotor rpm, and simultaneously moved the cyclic control forward and to the right to avoid the power lines. After rotor rpm was regained, the pilot increased torque to 100 to 103 percent "to keep the helicopter flying." He said the downdraft continued to push the helicopter towards the ground and the LOW ROTOR RPM horn continued sounding. The pilot said he "decreased collective with forward airspeed with the cyclic" in an attempt to fly out of the downdraft, but to no avail. The helicopter's aft skids struck snow-covered terrain and "dug in." The helicopter rolled "once or twice" and came to rest on the underside of the fuselage.
the pilot's inadvertent flight into adverse weather, which resulted in a collision with terrain. A contributing factor was the downdraft.
Source: NTSB Aviation Accident Database
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