Primary finding
Probable cause
The instructor pilot's inadvertent excessive descent rate, and his delay of remedial action during the demonstration of a 180 degree autorotation.
Investigator assessment
Analysis narrative
While demonstrating a 180 degree autorotation to landing, the instructor pilot inadvertently allowed the helicopter to attain an excessive rate of descent. Although he added power and initiated a go-around, he had waited too long to begin the go-around, and he was unable to keep the helicopter from impacting the end of the runway and bouncing back into the air. After hover-taxiing to parking, the instructor inspected the helicopter, whereupon it was determined it had sustained substantial damage.
Source record
Factual narrative
While demonstrating a 180 degree autorotation to landing, the instructor pilot inadvertently allowed the helicopter to attain an excessive rate of descent. Although he added power and initiated a go-around, he had waited too long to begin the go-around, and he was unable to keep the helicopter from impacting the end of the runway and bouncing back into the air. After hover-taxiing to parking, the instructor inspected the helicopter, whereupon it was determined it had sustained substantial damage.