Aviation Accident Summaries

Aviation Accident Summary DEN99LA002

VERNAL, UT, USA

Aircraft #1

N992SM

Bell 206B

Analysis

THIS CASE WAS MODIFIED DECEMBER 20, 2005. The pilot was attempting to land in a strong quartering tailwind because his passenger had become air sick. He said the helicopter 'was practically in a hover [with] full power applied. . .when a gust of wind from behind hit me just as I was turning into the wind using left pedal. The helicopter weather vaned, I reacted with full right pedal and then the gust either stopped or came from a different direction weather vaning us back to the west where I applied full left pedal. I could feel buffeting in the controls similar to turbulence. The right yaw was so rapid that I entered loss of tail rotor effectiveness.' The helicopter collided with terrain while it was still turning and rolled over. According to the passenger, the pilot had attempted landings earlier in the day but had difficulty with the wind. He succeeded in landing after several attempts.

Factual Information

THIS CASE WAS MODIFIED DECEMBER 20, 2005. On October 3, 1998, approximately 1730 mountain daylight time, a Bell 206B, N992SM, was substantially damaged when it collided with terrain during landing near Vernal, Utah. The private pilot and his passenger were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal cross-country flight being conducted under Title 14 CFR Part 91. The flight originated at Steamboat Springs approximately 1700. According to the pilot's accident report, his passenger became air sick and he was attempting to land with a strong quartering tailwind. The pilot said the helicopter "was practically in a hover [with] full power applied...when a gust of wind from behind hit me just as I was turning into the wind using left pedal. The helicopter weather vaned, I reacted with full right pedal and then the gust either stopped or came from a different direction weather vaning us back to the west where I applied full left pedal. I could feel buffeting in the controls similar to turbulence. The right yaw was so rapid that I entered loss of tail rotor effectiveness." The helicopter collided with terrain while it was still turning and rolled over. According to the passenger's statement, the pilot had attempted to land at Kremmling, Colorado, earlier in the day but had difficulty with the wind. After several attempts, he landed. The passenger also stated he felt the difficulties with the landings at Kremmling, Colorado, and Vernal, Utah, was due to "low clouds, rain and poor visibility." Visual meteorological conditions prevailed at Unitah County Airport, Vernal, Utah, located 35 miles west of the accident site. The helicopter's left skid and main rotor blades were severed on impact.

Probable Cause and Findings

Loss of tail rotor effectiveness. A factor was the quartering tailwind.

 

Source: NTSB Aviation Accident Database

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