Accident Sequence
A pilot was conducting aerial reindeer herding operations in a skid-equipped Brantly B-2B helicopter. While in a high hover, the pilot observed several left yaw movements followed by an uncommanded left yaw. He decided to perform a precautionary landing on "knee-high" tussocks in remote tundra. The pilot initiated a hovering autorotation from about 15 feet above ground level. During landing, the left skid assembly became damaged, causing the helicopter to settle forward and to the left. This resulted in all three main rotor blades impacting the tundra. The blades separated mid-span, and the helicopter sustained substantial damage to the main rotor system and fuselage.
Postaccident Findings
After the accident, the pilot spoke with a witness who reported hearing the engine produce "popping" noises followed by the engine quitting. At the time, the pilot stated he was unaware that the engine had lost power. A postaccident examination by the pilot found no preimpact mechanical malfunctions with the airframe or engine that would have precluded normal operation. Inspection of the fuel cell revealed approximately 1/8 cup of water mixed with about 5 gallons of remaining fuel.
Fuel Contamination
During the day's operations, the helicopter had been shut down for refueling several times, with no hot refueling conducted. The pilot learned from local community members assisting him that before the accident flight, fuel was transferred from a steel drum using a pump system into a plastic jug for pouring into the helicopter. A water separating filter/funnel was not used by the assistant, who mistakenly believed filtering would occur during pouring. Subsequent inspection found water in the steel drum. The pilot reported performing a preflight check of the helicopter's fuel sump before the accident flight, with no discrepancies observed.
Tundra Boards Discussion
The pilot noted that the helicopter was not equipped with tundra boards on the skids at the time of the accident. He stated that, based on his research, no commercial companies held a supplemental type certificate (STC) for tundra boards for the Brantly B-2B. He felt uncomfortable pursuing an FAA field approval to create his own boards due to lack of an engineering background. He believed tundra boards would distribute the helicopter's load on tundra, potentially preventing skid movement or sinking, and that their presence might have kept the left skid intact during the autorotation. The FAA Rotorcraft Standards Staff confirmed no approved or in-work STC existed for such devices on the Brantly B-2B.
The helicopter was not equipped with an emergency locator transmitter, nor was it required to be. The FAA Advisory Circular 20-125 (Water in Aviation Fuels, 1985) highlights the hazards of water in fuel, emphasizing the pilot's responsibility to ensure proper fueling and cautioning against refueling from drums or cans without careful inspection.