Incident Overview
A pilot conducting an aerial application flight was on his third pass when he momentarily glanced at his global positioning system (GPS). During that brief distraction, the left spray boom struck the ground. The pilot reported that the spray boom then wiggled back and forth before folding back into the tail boom.
Sequence of Events
After the spray boom contacted the ground, the helicopter began to spin to the right. The pilot initiated an autorotation to manage the descent. The helicopter landed hard but remained upright following the touchdown.
Extent of Damage
Examination of the helicopter revealed that the spray boom, tail rotor, and tail rotor gear box had completely separated from the airframe. Additionally, the fuselage and main rotor blades sustained damage. The operator reported that no mechanical deficiencies were present prior to the accident.
Pilot Actions
The pilot stated that he glanced at the GPS just before the spray boom struck the ground. He further described the spray boom's movement after impact and his subsequent decision to enter autorotation as the helicopter spun.