What happened
The flight was conducted primarily for training purposes, with the specific objective of practicing autorotations. During one of these practice maneuvers, the student pilot developed an excessive sink rate. The flight instructor was slow to intervene and correct the situation. Consequently, the helicopter executed a run-on landing into a field characterized by uneven terrain.
Post-flight examination conducted the morning after the incident revealed substantial damage to the helicopter. At the time of the accident, the wind was from 280 degrees at 15 knots, gusting to 21 knots.
The investigation
A post-flight examination was performed on the morning following the incident. This inspection identified substantial damage to the helicopter structure and systems.
Findings
The primary factor in this incident was the student's development of an excessive sink rate during the autorotation practice. The flight instructor's delayed reaction contributed to the inability to prevent the run-on landing. The uneven terrain of the landing area exacerbated the impact. The flight instructor later recommended that autorotational training be conducted to a runway or improved surface to mitigate such risks.