Accident Details
On August 14, 2008, about 1400 Pacific daylight time, an experimental Kolb MK III airplane, N18EX, impacted terrain about one-quarter mile south of the runway at Richland Airport, Richland, Washington. The student pilot, who was the sole occupant, was killed. The airplane was owned and operated by the pilot and was being flown in visual meteorological conditions. The pilot intended to stay in the traffic pattern during the personal flight under 14 CFR Part 91. No flight plan was filed.
Witness Observations
Witnesses reported that about 20 minutes before the accident, the pilot flew another small experimental or ultralight airplane. During that flight, he took off from runway 01, climbed to about 200 feet above ground level (agl), leveled off, and shortly after executed a 180-degree reversal turn, placing him on a low-level downwind. He then turned onto a base leg and rolled out on a short final for landing. Witnesses characterized this as a short, tight, low-level traffic pattern. They stated the pilot flew at this airport almost daily and believed he used such patterns to reduce circuit time in his light, slow airplane.
During the accident flight, the pilot took off, climbed to about 200 feet agl, leveled off, made small power adjustments, and then entered a "steep" right turn. As the airplane passed through nearly 180 degrees of turn, its bank angle increased to almost 90 degrees, and the pilot appeared to add substantial power. Almost immediately, the airplane appeared to stall and descend steeply into the terrain.
Post-Accident Examination
The engine, mounted in a pusher position, was reportedly running strong and smooth during the descent and continued for at least 15 seconds after impact. The fuel tank was at least three-quarters full. A post-accident inspection by an FAA Airworthiness Inspector found no anomalies or malfunctions that would have contributed to an in-flight loss of control. A partial teardown of the engine showed the ignition system could produce spark, the fuel system provided adequate fuel, and the air induction system was unobstructed.
Toxicology and Autopsy
An autopsy by the Benton County Coroner determined the manner of death as "accidental" and the mechanism as "respiratory arrest secondary to central nervous system damage." Toxicology tests were negative for ethanol in blood and vitreous fluid, no CNS drugs were detected, and carbon monoxide concentration was less than five percent saturation.