NTSB Identification: ANC08TA028
On December 20, 2007, about 0123 New Zealand daylight time, a turbine powered, wheel/ski-equipped Douglas DC-3T, C-FMKB, sustained substantial damage during an on-ground collision with snow-covered terrain during takeoff from a remote site, about 547 miles east of McMurdo Station, Antarctica. The airplane was being operated by the National Science Foundation's Antarctica Mission as a public use flight. The airplane and crew were provided under contract to the National Science Foundation by Kenn Borek Air, Ltd., Calgary, Alberta, Canada. Of the 10 people on board, the airline transport pilot and eight passengers sustained no injuries, and the first officer sustained minor injuries. Visual meteorological conditions prevailed, and company flight following procedures were in effect.
The National Science Foundation public use aircraft contract with Kenn Borek Air, Ltd., is administered by the United States Department of the Interior (DOI), Aviation Management Directorate (AMD).
During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on December 23, about 1310 Alaska standard time, the accident captain reported that the purpose of the flight was to provide aviation support services to the scientific research team. He noted that the outbound flight to a prearranged site near Mt. Paterson was uneventful. After arriving at the site, the research team installed a monitoring station, which required about 5 to 6 hours to complete. The captain said both he and the first officer remained at the airplane and waited for the research team to complete the installation. Once the research team completed their work, they returned to the airplane, and the airplane was prepared for departure.
The captain reported that his takeoff site consisted of hard packed, wind blown snow, which was atop a 5-degree down slope. He said that during the takeoff run, as the airplane neared 70 knots, he moved the airplane's control column aft in an attempt to lower the tail, and attain a flying attitude. He said that just before the airplane became airborne, the right wing lifted and left wing struck the snow-covered terrain, which pivoted the airplane 90 degrees to the left. He said that both main landing gear assemblies collapsed, and the airplane came to rest on its belly.
During a telephone conversation with the NTSB IIC on December 26, about 0945 Alaska standard time, the first officer reported that during the takeoff run, as the airplane neared 60 knots, and as the captain moved the control column aft, she felt the airplane's tailwheel contact the hard packed snow. She said she told the captain the airplane was not going to fly just before the left wing struck the snow-covered terrain. She added that as the airplane pivoted to the left, her seatbelt buckle opened, and she subsequently struck her head on the cockpit overhead console before the airplane stopped.
The first officer noted that other DC-3T captains that she had flown with used a higher takeoff airspeed, closer to 70 knots instead of 60 knots. She added that a typical takeoff rotation airspeed speed is about 73 to 75 knots for an airplane operating at a similar gross weight. The airplane sustained substantial damage to the left wing and fuselage.
The captain and first officer both reported that there were no preaccident mechanical anomalies with the airplane.
The Cockpit Voice Recorder (CVR) was removed from the airplane and sent to the NTSB vehicle recorder laboratory in Washington, DC. A Safety Board aerospace engineer reviewed the recorded data. No CVR listening group was convened, but a summary of key events of the accident flight was prepared.
According to the data contained on the CVR, about 26 seconds before impact, the captain instructed the first officer to: "Set power," and the first officer responded by saying: "Powers set." About 6 seconds later the first officer said: "Airspeed’s alive." About 12 seconds after that, the first officer said: "It’s not gunna come off," followed about 3 seconds later with: "There’s sixty [knots]." About 3 seconds afterward the first officer says: "Ah ____" (expletive), which was followed by the sound of impact.
A copy of the CVR summary is included in the public docket for this accident.
