Accident Overview
On July 14, 2012, at 1750 central daylight time, a Robinson Helicopter Company model R44 II, registration N556MM, was substantially damaged when it impacted a ground-support vehicle while landing near Red Oak, Iowa. The commercial pilot was not injured. The helicopter was registered to and operated by Johnson Helicopter Services LLC under 14 Code of Federal Regulations Part 137, conducting a local aerial-application flight without a flight plan. Day visual meteorological conditions prevailed for the flight, which originated from an agricultural field near Red Oak about 1745.
Pilot Report
The pilot reported that after takeoff, he was unable to activate the motorized spray system upon arriving at the field to be sprayed. He returned to the departure location to troubleshoot the inoperative system. While maneuvering the helicopter to land next to a ground-support vehicle, the main rotor system impacted a landing platform installed on top of the vehicle. Following the impact, the pilot noted a vibration throughout the helicopter and elevated cyclic stick pressures. The main rotor system, tail boom, and fuselage were damaged during the accident sequence. The pilot stated that there were no preimpact mechanical malfunctions or failures that would have precluded normal operation of the helicopter.
Weather Information
The closest weather observing station, Red Oak Municipal Airport (KRDK), located about 5 miles south of the accident site, reported at 1755: calm wind, visibility 10 miles, temperature 33 degrees Celsius, dew point 22 degrees Celsius, altimeter setting 29.97 inches of mercury. The sky condition was not reported.