19980919025519A

Helicopter took off, climbed to about 500 feet AGL, and desceded steeply into a soybean field. (-23)based on witness statements; shortly after takeoff from cps at an altitude of approximately 150-200 feet, engine noise stopped, the aircraft's nose dipped, the pilot attempted to autorotate. The aircraft impacted the ground with excessive force critically injuring pilot and causing destruction of the aircraft. (.4) a witness watched the helicopter as it climbed out after takeoff. The witness said that the helicopter was higher than the telephone lines which ran northeast of the airport. 'He was level and climbing, going away from me when all of a sudden, the sound (engine sound) went quiet, followed by a pop. It was not a loud pop.' The helicopter began a shallow descent. At about 30 to 40 feet above the field, the helicopter 'leveled out,' but 'kept coming down.' The witness said he saw the helicopter 'hit' and then 'cartwheel.' Examination of the helicopter's engine revealed scoring marks on the power-takeoff cylinder (front cylinder) piston, and impact marks in the head. Small metallic particles were embedded in the piston head. The power-takeoff cylinder wall showed scuff marks, and the cylinder head showed impact marks. The two power-takeoff spark plugs showed no gap at the electrodes, and impact marks. No other anomalies were revealed.