SEA94LA143

The pilot elected to take off during high speed taxi runs after encountering control difficulties. He added power, but did not add full power. When he noted his slow airspeed, he added full power and the engine sputtered. The aircraft mushed, then stalled and impacted the terrain before power could be regained. Later testing revealed that the electric boost pump was not functioning properly and insufficient fuel flow was available at higher power settings.

On May 28, 1994, at 0813 Pacific daylight time (PDT), an experimental Wray KR-2, N786RW, impacted terrain after takeoff at Thun Field, Puyallup, Washington. The private pilot, who was the sole occupant of the aircraft, was uninjured and the aircraft sustained substantial damage. The test flight was conducted in visual meteorological conditions. There was no flight plan filed and the ELT was shut off at the site.

The pilot was conducting slow and high-speed taxi testing of the aircraft, with the intent to add power and take off if he encountered difficulties during the test runs. During a high- speed run, he had oscillations about the pitch axis, followed by the aircraft heading toward the left edge of the runway. The pilot reported that he elected to add power and take off. After takeoff he realized that he was just above stall speed at 75% power. He reported pushing in full throttle and the engine sputtered to a low idle. The pilot stated that the aircraft mushed, slowed, then broke quickly, rolling to the left before impacting the terrain.

Later testing by the owner/manufacturer of the aircraft determined that the electric boost pump was not functioning properly, and insufficient fuel flow was available at higher power settings.