Eurocopter AS 350 B2 N406EM accident near Hugo, Oklahoma

Probable cause

The pilot’s inadequate collective control inputs while performing a hovering autorotation, which resulted in a hard landing. Contributing to the accident was the check airman's delayed remedial action.

NTSB analysis

A check airman was giving the pilot-in-command (PIC) an annual check ride with night vision goggles in the emergency medical service helicopter. After a satisfactory slope landing, the PIC repositioned the helicopter to a flat area and performed a hovering autorotation, which resulted in a hard landing. The check airman then demonstrated a second hovering autorotation, and the PIC performed another hovering autorotation that was satisfactory. The check airman continued the annual check ride. After the flight, during a post-flight examination, substantial damage was discovered to the tail boom and the aft portion of the fuselage. The damage was consistent with a hard landing, presumably incurred during the first hovering autorotation in which the helicopter landed hard. In a statement provided to the NTSB, the check airman said that he should have guarded the collective more to limit the amount of control input during the practice autorotation maneuvers.

Text from the NTSB. Open the NTSB docket for CEN12CA269 for the full record.