Primary finding
Probable cause
The pilot's inadequate compensation for wind conditions while the helicopter was standing, which resulted in the coasting main rotor blade contacting the tail boom. A factor associated with the accident was the gusty wind condition.
Investigator assessment
Analysis narrative
The commercial helicopter pilot said he landed on a ridge where he had landed several times that day. He said he shut down the engine, and was applying the main rotor brake when a gust of wind lifted the forward blades, which allowed the aft moving blades to strike the tail boom. The pilot said there had been a steady 20 knot wind blowing at the site all day, but there were no problems with wind gusts on the previous landings. The main rotor blades and tail boom were damaged during the accident.
Source record
Factual narrative
On July 11, 2004, about 1415 Alaska daylight time, a Canadian registered Hughes 369D helicopter, C-GLHQ, sustained substantial damage when a gust of wind resulted in the coasting main rotor blades striking the tail boom after landing at a remote site, about 80 miles northwest of Nome, Alaska. The helicopter was being operated by Prism Helicopter LTD, Wasilla, Alaska, as a visual flight rules (VFR) contract survey flight under Title 14, CFR Part 135 when the accident occurred. The commercial pilot and two passengers were not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on July 13, the pilot said he landed on a ridge where he had landed several times that day. He said he shut down the engine, and was applying the main rotor brake when a gust of wind lifted the forward blades, which allowed the aft moving blades to strike the tail boom. The pilot said there had been a steady 20 knot wind blowing at the site all day, but there were no problems with wind gusts on the previous landings. He said there were no known mechanical anomalies with the helicopter prior to the accident, and that the main rotor blades and tail boom were damaged during the accident.