Chickaloon, AK, USA
N7183P
Robinson R-44
The pilot was transporting two search and rescue volunteers and their equipment to the scene of an avalanche in a float-equipped helicopter. A helicopter landing zone (heli spot) had been established the evening before the accident, near the toe of the avalanche. The heli spot had been used by a military helicopter, and was marked by small flags. The surface of the snow at the heli spot had been dusted by red powder. The pilot of the accident helicopter had not landed at the heli spot before. The heli spot was located at 5,300 feet msl, near the bottom of a small valley. The pilot began his landing approach toward the west. Although the weather conditions were clear, the pilot said the lighting conditions in the valley provided little contrast (flat light). The pilot said that as he began to add power near the termination of the landing approach, the low rotor warning horn sounded, and he noticed that the main rotor gauge was indicating 92 to 94 percent. He reduced collective pitch, ensured the throttle was full open, and began to initiate a go-around toward the west, an area of lower terrain. The helicopter continued to descend, and the right front portion of the landing gear float assembly contacted the snow. About the same time, the main rotor contacted the slope of a small, snow-covered hill, to the right of the helicopter. The helicopter then rolled onto its right side. After the accident, the pilot said he noted that the wind was blowing about 8 knots from the east.
On February 4, 2001, about 0930 Alaska standard time, a float-equipped Robinson R-44 helicopter, N7183P, sustained substantial damage while landing in a remote area, about 35 miles east-northeast of Chickaloon, Alaska. The helicopter was being operated as a visual flight rules (VFR) government-operated flight under Title 14, CFR Part 91, when the accident occurred. The helicopter was operated by the State of Alaska, Department of Public Safety. The airline transport certificated pilot, and the two passengers, were not injured. Visual meteorological conditions prevailed. The flight originated at the Eureka Lodge, Eureka, Alaska, about 0915. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on February 4th, the pilot, who is the supervisor for the State of Alaska's Aircraft Section, reported that he was transporting two search and rescue volunteers and their equipment to the scene of an avalanche. The avalanche was about 11.3 miles south-southeast of the Eureka Lodge. Utilizing the accident helicopter, the pilot had been involved in search operations at the avalanche site the evening before the accident. A helicopter landing zone (heli spot) had been established the evening before the accident, near the toe of the avalanche. The heli spot had been used by a military helicopter, and was marked by small flags. The surface of the snow at the heli spot had been dusted by red powder. The pilot of the accident helicopter had not landed at the heli spot before. The heli spot was located at 5,300 feet msl, near the bottom of a small valley. The pilot said he began his landing approach toward the west. Although the weather conditions were clear, the pilot said the lighting conditions in the valley provided little contrast (flat light). The pilot said that as he began to add power near the termination of the landing approach, the low rotor warning horn sounded, and he noticed that the main rotor gauge was indicating 92 to 94 percent. He reduced collective pitch, ensured the throttle was full open, and began to initiate a go-around toward the west, an area of lower terrain. The helicopter continued to descend, and the right front portion of the landing gear float assembly contacted the snow. About the same time, the main rotor contacted the slope of a small, snow-covered hill, to the right of the helicopter. The helicopter then rolled onto its right side. After the accident, the pilot said he noted that the wind was blowing about 8 knots from the east. The passengers on board the helicopter reported hearing the low rotor warning horn as the helicopter was about 100 feet above the ground in a small gully area. They said there was little contrast to define the terrain. They reported the temperature as 25 degree F. The pilot said the temperature was 10 degrees F. The helicopter has a gross weight of 2,400 pounds. A postaccident review of the helicopter's loading and performance calculations revealed the helicopter was loaded to about 100 pounds below maximum gross weight. According to the manufacturer's performance charts, at 2,300 pounds, the out-of-ground effect hover ceiling at 10 degrees is about 5,300 feet, at 25 degrees, the hover ceiling is about 4,700 feet. The in-ground-effect hover ceiling (a two foot hover height) at 10 degrees is about 8,400 feet, at 25 degrees, the hover ceiling is about 7,800 feet. The State of Alaska's Aircraft Manual, Revised March 2000, Section IV, (B) 1., lists pilot qualifications. The manual indicates that the minimum experience in the accident helicopter (Robinson R-44) is 200 hours. In the NTSB Pilot/Operator report submitted by the pilot, the pilot indicated having accrued 381 hours in helicopters, with 221 hours in a Robinson R-44. Section IV, (B) 9. b), lists pilot currency requirements by stating that helicopter pilots must, within the last 90 days, have at least 10 flight hours. The pilot indicated he accured 9.4 hours in the accident helicopter in the previous 90 days, 7.1 hours in the previous 30 days, and 2.4 hours in the previous 24 hours.
The pilot's collision with terrain due to his inadequate planning of the approach, and his failure to maintain the helicopter's main rotor RPM during a go-around. Factors in the accident were a tailwind, flat lighting conditions, and snow-covered terrain.
Source: NTSB Aviation Accident Database
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