NTSB Factual Report

On March 1, 2001, approximately 1550 mountain standard time, a Meshko-Zenair CH-701, N4386W, was substantially damaged when it collided with the ground during a forced landing in a field north of Platte Valley Airpark, Hudson, Colorado. The private pilot, the sole occupant in the airplane, received serious injuries. Visual meteorological conditions prevailed, and no flight plan was filed for this personal flight being conducted under Title 14 CFR Part 91. The flight had originated at Greeley-Weld County Airport, Greeley, Colorado, at approximately 1530.

According to the pilot's accident report, he had just taken off and was climbing at 80 percent power (5,000 rpm) when he noticed the exhaust gas temperature (EGT) rising "into redline 1,625 degrees F." The pilot leveled off, reduced power to 4,800 rpm, and reduced propeller pitch. The EGT stopped rising and came down slightly, but was still above redline. All other engine indications were normal. EGT continued to rise and the engine started losing power and "running rough." The airplane began losing altitude so the pilot slowed to 45 mph and selected an open field. He flared "at [the] last moment [and] hit [the] ground sharply." The nose wheel ran over a tire track in the ground and was sheared off. The strut dug into the ground and the airplane nosed over.

The pilot, who was also the builder of the airplane, suspected detonation caused the rise in EGT.

NTSB Probable Cause

the loss of engine power as a result of detonation. A contributing factor was the unsuitable terrain on which to make a forced landing.