Accident Overview
On June 2, 2018, about 1025 Alaska daylight time, a Piper PA-18-150, registration N624MW, sustained substantial damage during a forced landing after a total loss of engine power. The accident occurred near Lawrence Airstrip (55AK) in Wasilla, Alaska. The airplane was operated by the private pilot under 14 Code of Federal Regulations Part 91 as a visual flight rules flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight had departed 55AK about 1023, destined for Big Lake, Alaska.
Pilot Report
According to the pilot, all engine power was lost shortly after departure. The pilot reported no sights or sounds consistent with a catastrophic engine failure; the engine ceased operation consistent with fuel starvation. The pilot stated that the left fuel tank was about half full, the right fuel tank was empty, and the fuel selector was positioned to "BOTH."
Forced Landing and Impact
During the forced landing, the pilot attempted to return to the runway but impacted a forested area of tall spruce and birch trees. The impact resulted in substantial damage to the wings and rudder.
Engine Examination
On July 11, 2018, the engine, a Lycoming O-320-A2B, was examined at Alaska Claims Services under the supervision of National Transportation Safety Board investigators. Prior to removal, the gascolator was drained and small amounts of unidentified contaminants were found. The carburetor bowl was also drained, revealing more minute contaminants.
Engine Test Run
The engine was removed from the airframe and transported to Alaska Aircraft Engines in Anchorage, Alaska. On July 17, it was attached to an engine test truck with a four-bladed wooden club propeller. The engine started within three seconds and was warmed at idle power for five minutes. It was then run at idle and maximum power for five minutes each, followed by rapid manipulations from idle to maximum continuous power. No hesitations or anomalies were observed throughout the test run.