Accident Overview
A pilot reported that during the takeoff roll, the airplane decelerated. He applied the brakes and then advanced the throttles to full power, after which the airplane accelerated. The aircraft cleared the end of the runway, stalled into Lake Michigan, flipped inverted, and sank. One passenger reported feeling as if someone had applied the brakes. One passenger drowned.
Pilot Actions and Aircraft Performance
The pilot used 32 inches of manifold pressure for takeoff, while the placarded value was 37.3 inches. According to the pilot operating handbook, normal takeoff speed is 91 KIAS, but the airplane was equipped with vortex generators. The pilot stated he was looking for 105 to 110 KIAS for takeoff.
Investigation Findings
No evidence was found of the pilot having a multi-engine rating. No evidence of a mechanical failure or malfunction was discovered during the investigation.
Probable Cause
The official probable cause was determined to be: The pilot's improper use of the throttle in not using full power for takeoff, the pilot's failure to use proper aborted takeoff procedures, and the inadvertent stall/mush. A factor associated with the accident was inadequate preflight/planning by the pilot.