The pilot, who was in training to add a helicopter rating to his pilot certificate, said he had just departed for a solo flight. He accelerated the helicopter to cruise flight and noticed an “unusual vibration.” He performed an immediate precautionary landing straight ahead. During the touchdown sequence, one of the helicopter’s landing skids hit a tree branch, and the helicopter rolled onto its side. The helicopter’s main rotor impacted the tail boom, which separated from the fuselage. Several days after the accident, the pilot flew with his flight instructor in a different helicopter and attempted to replicate the vibration. As a result of this flight, the pilot believes that, during the accident flight, he encountered a tailwind and that there was nothing wrong with the helicopter.