Incident Overview
A helicopter was conducting straight-in autorotations with power recoveries during a training flight. The flight instructor and student were practicing the maneuver, with the student acting as the primary manipulator of the controls for the first four approaches. The student had been initiating the flare too high, prompting the instructor to suggest performing the next approach together with both individuals on the controls.
Sequence of Events
During the flare portion of the subsequent autorotation, the helicopter's stinger struck the runway surface. Following this, the tail rotor contacted the ground, causing the helicopter to yaw 360 degrees to the right. The aircraft came to rest approximately 100 feet from the initial point of impact, at which point the tail rotor again struck the runway. The impact of the main rotor severed the tail boom.
Instructor's Account
The instructor reported his belief that the student had misinterpreted the instructions. The instructor had intended for the student to make control inputs to initiate the flare, with the instructor merely following through on the controls to guide the student to flare at a lower altitude than on previous attempts. However, the student understood the instruction to mean that the instructor would be making the primary control inputs. The instructor stated that the accident could have been prevented through better communication between student and instructor, specifically regarding who is responsible for initiating control inputs during all phases of flight, especially critical phases.