What happened
On June 17, 2016, an Airbus AS3pend350 operated by the US Department of Homeland Security was undergoing an engine run-up sequence in McAllen, Texas. The helicopter was positioned on a movable pad attached to a tug.
During the procedure, the pilot noticed that the right rear door was not properly secured. To reach the door, the pilot unhooked his shoulder harness. While attempting to secure the door, the pilot applied the right tail rotor pedal by mistake. This input caused the N4035W to spin to the right multiple times. During the rotation, the aircraft moved off the movable pad and struck the tug before coming to rest upright on the ground. There were no injuries resulting from the accident.
The investigation
The investigation confirmed that the helicopter sustained substantial damage to its vertical stabilizer. The pilot reported that there were no mechanical failures or malfunctions involving the engine or airframe prior to the impact that would have prevented normal operation.