Accident Overview
On September 6, 2009, at approximately 1735 Alaska daylight time, a Robinson R44 II helicopter, registration N4186Y, sustained substantial damage during a hard landing while approaching a mountain ridge about 38 miles southeast of Central, Alaska. The helicopter was operated by Alpine Air Alaska, Inc., of Girdwood, Alaska, as a visual flight rules (VFR) on-demand charter flight under Title 14 Code of Federal Regulations Part 135. The airline transport pilot and two passengers were not injured.
Flight Details
The flight departed Fairbanks International Airport, Fairbanks, Alaska, around 1400, en route to various communication sites near Central. Visual meteorological conditions prevailed, and company flight following procedures were in effect.
Pilot Report
According to the pilot, the purpose of the flight was to transport two maintenance technicians to mountaintop radio repeater sites. Before approaching the 5,657 feet mean sea level site, he circled to assess wind conditions and planned an approach into a 10-knot headwind. During the approach to the treeless, tundra- and rock-covered landing area, the pilot encountered a strong downdraft, causing the helicopter to descend below his intended path. He initiated a go-around, but the helicopter continued descending and landed hard approximately 150 feet short and downslope of the intended touchdown point.
Damage
During touchdown, the toes of the helicopter's skids broke, and the helicopter rocked forward and aft. The right side of the tail boom sustained substantial damage.
Wind Conditions
The pilot characterized wind conditions on the ground as variable, gusting between 10 and 20 knots.
Mechanical and Operational Notes
The pilot reported no preaccident mechanical problems with the helicopter. In his written statement, he recommended relocating the landing site to an area above the ridge to minimize exposure to downdrafts and installing a functioning windsock. In April 2010, a representative from Alpine Air reported that the owner of the remote radio repeater site had installed a new windsock and was considering relocating the existing landing site.