On December 16, 2002, at 0903 mountain standard time, an experimental Anderson Rotorway Exec 162F helicopter, N30545, rolled over during a hard landing following a loss of engine power on final approach to Deer Valley Airport (DVT), Phoenix, Arizona. The owner was operating the helicopter under the provisions of 14 CFR Part 91. The instructor and the student/owner were not injured; the helicopter sustained substantial damage. The local area instructional flight departed DVT at 0902. Day visual meteorological conditions prevailed, and no flight plan had been filed. The Federal Aviation Administration (FAA) accident coordinator interviewed the instructor and student. During a normal takeoff, approximately 300 feet above ground level (agl), a sudden loss of engine power occurred, but power was quickly regained. The helicopter continued to climb and about 500 feet agl, another power loss and recovery occurred. The instructor then executed a normal approach to land. As he increased power during the landing flare, a loud "growling" noise was heard followed by a reduction of rotor rpm and power. The helicopter made ground contact in a flat attitude but with forward speed. The tail of the helicopter moved upward, which resulted in the nose and main rotor blades contacting the ground. The helicopter rolled over and came to rest on its left side. The owner held a private pilot certificate with a single engine land airplane rating and was a student pilot in helicopters. The instructor held a flight instructor certificate for helicopters. A post accident engine examination was performed at Rotorway International in Chandler, Arizona, under the supervision of the FAA. The number 1 cylinder exhibited damage to the top of the piston and the inside of the cylinder head. The exhaust valve stem was broken. The number 1 piston had pieces broken off the periphery, which allowed oil to pass through to the top of the cylinder and foul the spark plugs. Repeated requests were made to the flight instructor and owner to complete Safety Board Form 6120.1/2, but no responses were received.