NYC01LA220

The pilot descended from 5,500 feet to 1,500 feet, at a moderate cruise power setting, at 5,500 rpm. About 1,500 feet above the ground, the two cycle 2-cylinder engine lost all power, and the pilot performed a forced landing to a field. The pilot believed that the descent at cruise power created a lean fuel/air mixture. Examination of the engine revealed scoring on both pistons, which was directly in line with the exhaust. According to a representative from the engine manufacturer, that type of failure was indicative of a heat seizure, normally associated with an excessive exhaust gas temperature, exceeding 1200 degrees F. The representative assumed that the engine was operating in a lean condition. According to the manufacturer's engine manual, during cruise and descents, it was very important that to avoid creating a lean mixture condition with high rpm and low throttle opening. Additionally, the manual warned that the engine was subject to sudden stoppage, and conformed to no aircraft standards.

On September 3, 2001, about 1315 eastern daylight time, an amateur built Mini Max 1500R, N962JA, was substantially damaged during a forced landing near Chesapeake, Virginia. The certificated private pilot was not injured. Visual meteorological conditions prevailed for the flight that departed a private airport in Saluda, Virginia; destined for Hampton Roads Executive Airport (PVG), Chesapeake, Virginia. No flight plan was filed for the personal flight conducted under 14 CFR Part 91.

The pilot stated that he began a descent from 5,500 feet, toward PVG. During the descent, he maintained a "moderate cruise" power setting, at 5,500 rpm. About 1,500 feet above the ground, the two cycle 2-cylinder Rotax engine lost all power, and the pilot performed a forced landing to a field. During the landing, the airplane struck small trees and sustained substantial damage to the right wing.

The pilot added that the engine experienced a "cold seizure." He believed that the descent at cruise power created a lean fuel/air mixture and subsequent lack of lubrication.

A Federal Aviation Administration inspector examined the airplane. The inspector observed that both pistons exhibited scoring. Photographs of the damaged pistons and cylinders were forwarded to a representative from the engine manufacturer.

According to the manufacturer representative, the failure was directly in line with the exhaust, which was more indicative of a heat seizure, rather than a cold seizure. The representative further stated that a heat seizure was normally associated with excessive exhaust gas temperature, exceeding 1200 degrees F. He assumed that the engine was operating in a lean condition.

An excerpt from the manufacturer's make and model engine manual revealed:

"During cruise and descending it is very important not to create a lean condition with high rpm and low throttle opening. The less fresh charge the engine gets, the more hot residual gas remains in the cylinder. This raises the temperatures to a critical level. For this reason, you may also experience higher exhaust gas and cylinder head temperatures at reduced throttle openings."

Another excerpt from the manual revealed:

"Danger! This engine, by its design, is subject to sudden stoppage! Engine stoppage can result in crash landings. Such crash landings can lead to serious bodily injury or death.

Never fly the aircraft equipped with this engine at locations, airspeeds, altitudes, or other circumstances from which a successful no-power landing cannot be made, after sudden engine stoppage.

Warning! Although these engine types have undergone considerable durability testing, this engine is not a certified aircraft engine. It has not received any individual safety or durability testing and conforms to no aircraft standards. It is for use in experimental and ultralight uncertified aircraft and vehicles only, in which an engine failure will not compromise safety.

User assumes all risk of use and acknowledges by his use the he knows this engine is subject to sudden stoppage."