Accident Details
A pilot reported an accident while landing a helicopter on a trailer used for transport after completing a forest spray application. According to the pilot, he placed the landing skids on the trailer and lowered the collective to the full down position. The helicopter then abruptly tilted aft on the skid heels, prompting the pilot to apply up collective. The helicopter began rotating to the right, and the pilot was unable to counter the rotation using the left anti-torque pedal. As the helicopter completed a 180-degree right rotation, the pilot closed the throttle. The helicopter subsequently contacted the side of the trailer and came to a full stop with the engine no longer running. The pilot then shut off the battery master switch and disconnected the battery to prevent potential ignition of fuel.
Contributing Factors
The pilot reported that the trailer was parked on an uneven surface with the up side at the tail of the helicopter. He believed that the slope, combined with his abrupt movement of the collective, caused the tail rotor to come into contact with the trailer deck. The pilot also stated that the accident could have been avoided if the trailer had been on level terrain and if he had waited to lower the collective until after establishing positive and complete full landing skid gear contact with the trailer surface.
Mechanical Status
The pilot reported no mechanical failures or malfunctions with the helicopter at the time of the accident.
Pilot Comments
In his report, the pilot emphasized that the uneven parking surface and his control inputs were key to the sequence of events. He noted that the tail rotor strike occurred as the helicopter rotated, and that a level trailer and delayed collective lowering might have prevented the accident.