WATKINS, CO, USA
N34CM
Hughes 369D
The instructor was demonstrating autorotation techniques to his student. He stated at a speed of less than 10 knots, he entered a 'hovering auto(rotation)' to runway 17 from an altitude of 3 feet agl. He estimated the wind to be from 170 degrees at 12 to 15 knots. Recorded wind at Denver International Airport, located 10 miles northwest of the accident site, was from 290 degrees at 12 knots. The helicopter touched down and the main rotor blades struck the tail boom. The pilot said this was a 'fairly common occurrence' with this particular helicopter make and model operating under 'low rotor rpm and gusty wind.' A spokesman for the helicopter manufacturer said that if the helicopter had been landed upwind, the accident would not have occurred. He added that if gusty wind conditions were present, autorotation demonstrations should not have been attempted.
On October 19, 1996, approximately 1345 mountain daylight time, a Hughes 369D, N34CM, was substantially damaged when its main rotor blades struck the tail boom while landing at Watkins, Colorado. The certified flight instructor and private pilot receiving instruction were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for this training flight conducted under Title 14 CFR Part 91. The following is based on the Pilot/Operator Aircraft Accident Report. The instructor said he was demonstrating autorotation techniques to his student. He wrote, "During slow forward flight (less than 10 knots), hovering auto(rotation) was initiated at approximately 3 feet agl. Following a normal touch down, and deceleration, blades contacted tail boom." The instructor added, "Fairly common occurrence with 500 series helicopter under similar circumstances, i.e. low rotor rpm and gusty wind." According to a spokesman for the McDonnell Douglas Helicopter Company's Flight Safety Department, the accident is not a common occurrence. The spokesman said if the helicopter had landed upwind, the accident should not have occurred. He also stated that if gusty wind conditions were present, autorotation demonstrations should not have been performed. The pilot pilot said he landed on runway 17 and estimated the wind to be from 170 degrees at 12 to 15 knots. Recorded wind at Denver International Airport, located 10 miles northwest of Front Range Airport, was from 290 degrees at 12 knots.
The flight instructor's improper decision to attempt a hovering autorotation during gusty wind conditions. A factor was the gusty wind.
Source: NTSB Aviation Accident Database
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