LAX07LA184 · Brook Lancair IV-P

The pilot was about 1 hour 15 minutes into the flight, and the airplane was cruising at 26,000 feet, when the turbo prop engine lost power with white smoke coming out of the exhaust. About a minute before the pilot had observed what he termed "splats" of moisture on the windscreen. He performed an emergency descent and at 12,500 feet attempted an engine restart. The restart attempt was unsuccessful. He glided to the nearest airport, circled, and performed a power-off landing. The airplane crossed the runway threshold at 120 knots, floated, and touched down at mid field. After touchdown, the airplane continued down the runway, off the end, and into terrain and a fence. The airplane came to rest with the landing gear collapsed. Federal Aviation Administration inspectors examined the airplane, and could not identify any mechanical abnormality with the engine or fuel system. The Pilot Operating Handbook states that an engine relight was possible below 13,000 feet mean sea level, and below 160 knots of airspeed. The pilot could not recall what his airspeed was when he attempted the engine restart. The airplane was not equipped with any type of engine inlet anti-ice or deicing equipment. The pilot did state that he had been in and out of moisture while at his 26,000 feet cruising altitude, but there had been no ice buildup on his wings or windscreen. A technical representative for Lancair stated that a 3/4 blockage of the engine cowling NACA induction scoop might be enough to starve the engine of air and induce a flameout.

Verbatim NTSB analysis and probable cause from the NTSB dataset