20020730017239A

(-23) On 07-30-02 at approximately 0915 hours PDT, Mr. Andreas gschwari, a commercial-flight instructor pilot, was acting as pilot in command at the controls of a Robinson R-22 helicopter, giving flight instructor instruction to Mr. John sturdevant, a commercial-instrument helicopter pilot. A helicopter quick stop maneuver was initiated at approximately thirty feet above ground level in an apparent down wind situation. Due to a loss of rotor and engine RPM, the helicopter began to settle toward the ground. The helicopter made hard ground contact on a hill top and went airborne again. The second ground contact on the succeeding hill side was very hard resulting in the severing of the tail boom by the main rotor system, bringin the helicopter to a stop on its left side ninety degrees to the direction of travel. The instructor was not injured. The student received a bruise on the top of his left foot. There were no other injuries. The helicopter was substantially damaged but not destroyed as there was no fire. (.19) on July 30, 2002, at 0930 pacific daylight time, a Robinson R22 beta, N4074T, collided with the ground and rolled over while practicing quick st op maneuvers near fresno, California. The helicopter sustained substantial damage. The commercial licensed flight instructor and a dual primary student were not injured. The helicopter was operated by mazzei flying service under the provisions of 14 CFR part 91 of the federal aviation regulations. The local area instructional flight departed from the fresno air terminal, fresno, at 0900, and no flight plan was filed. Visual meteorological conditions prevailed. In a telephone interview, the flight instructor reported that they were practicing quick stop maneuvers. While in the flare, he applied collective and the low main rotor speed warning came on. Before he could recover the rotor RPM, the helicopter hit the ground and rolled over on it's left side. He stated that he did not perceive any mechanical malfunctions or failures.