Accident Overview
On April 12, 2015, at about 1645 Alaska daylight time, a tailwheel-equipped Cessna 170B, registration N4697C, sustained substantial damage following a total loss of engine power shortly after takeoff from an unimproved ski airstrip approximately 20 miles north of Bettles, Alaska. The certificated commercial pilot and two passengers were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed.
Pilot Report
During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge on April 13, 2015, the pilot stated that shortly after takeoff, at an altitude between 50 and 70 feet above ground level, a total loss of engine power occurred. After completing emergency procedures for an engine failure, the pilot lowered the nose to find a suitable landing area. Determining he could not reach the desired landing point, he arrested the descent and settled into an area of densely populated birch trees along a river, resulting in substantial damage to the airplane.
In a later conversation with an NTSB investigator on April 24, 2015, the pilot reported that prior to takeoff, he was unable to check the fuel tanks for contamination using the wing tank fuel drain valves because they were frozen and inoperable.
Post-Accident Examination
During a post-accident examination, the carburetor was removed from the engine, and the float bowl was found to be about half full with 100LL aviation fuel. The gascollator, electric fuel pump, and fuel lines were drained into a clean container, and no contamination was noted.
The engine, a Lycoming O-360, was removed and transported to Alaskan Aircraft Engines, Inc., in Anchorage, Alaska. On June 4, 2015, the engine was mounted to a test stand and operated under NTSB direction. It ran without anomalies and produced full factory-specified rpm. A drop of about 75 rpm was noted for the left magneto and about 100 rpm for the right magneto. A series of power adjustments from idle to full power showed no hesitation in engine operation.
Weather Information
The closest weather reporting facility is Bettles Airport, about 20 miles south of the accident site. At 1553, an aviation routine weather report (METAR) from Bettles Airport reported: wind from 150 degrees at 3 knots; scattered clouds at 3,000 feet, broken at 5,500 feet; visibility 10 statute miles; temperature 19°F; dew point 10°F; barometric pressure 29.53 inHg.