CHI08LA125

The flight was a short instructional flight in an experimental amateur-homebuilt airplane with a flight instructor with no flight time in the airplane, flying from the right seat. The flight was making a turn to base when the right seat instructor pilot reduced the power and the engine lost power. A forced landing was executed and the aircraft was substantially damaged upon impact with the ground. Inspection revealed no pre-accident anomalies with the engine. The right seat instructor pilot's recommendations were not to reduce power on a two stroke engine. The right seat instructor pilot also believed the left seat student pilot, with all the time in the aircraft, should have told him not to reduce power on the two stroke engine.

On May 4, 2008, at 1400 eastern daylight time, an experimental amateur-built Airaile, S-12 XL; N9148Y, crashed during a forced landing after losing power while turning to base leg for runway 35 at the Lexington County Airport, in Pelion, South Carolina. The instructor pilot in the right seat reported serious injuries and no injuries to the student pilot in the left seat. Visual meteorological conditions prevailed and the 14 CFR Part 91 instructional flight was not operating on a flight plan. The flight had departed about 5 minutes prior to the accident.

The right seat instructor pilot reported in the recommendations section of the pilot report that you should never reduce the power on a two-stroke engine. The right seat instructor also said that the left seat student pilot, who had all the time in the airplane, should have instructed him not to do the power reduction. Post accident inspection of the engine did not disclose any pre-accident anomalies with the engine. A Federal Aviation Inspector reported that the rear cylinder of this model engine will seize if the engine is throttled back in flight.