On October 26, 1997, at 1233 hours Pacific standard time, a Revolution Mini-500 experimental helicopter, N7234Y, was destroyed and the commercial pilot seriously injured when it impacted terrain following takeoff at Daugherty Field, Long Beach, California. The aircraft had completed one circuit of the helicopter traffic pattern and landed on Helo Pad 3. It was then cleared for a second circuit of the helicopter traffic pattern. The pilot stated that on the second takeoff, the engine quit abruptly at an altitude of 250-300 feet agl. He then attempted an autorotation, but could get only 80 percent rotor rpm which was insufficient to prevent a hard touchdown. (The pilot stated in his report that he felt this was due to a recent change in the main rotor low pitch stop from -1.8 deg. to -0.5 deg. which had been recommended by a factory representative.) The pilot also stated that he was aware of a phenomenon called "cold-freeze" (engine seizure without over temp) that had happened several times with the Rotax engine. He felt that a possible engine seizure, combined with the change in the rotor low pitch stop, were contributing factors to the accident rather than fuel starvation or mechanical malfunction of the helicopter.