Eurocopter AS350 N894NA accident near Ruidoso, New Mexico

Probable cause

The pilot's failure to maintain the proper descent rate during landing. Contributing to the accident were the pilot’s failure to conduct preflight performance calculations, which resulted in his operating the helicopter in high-density altitude conditions, and his lack of experience in high-altitude, mountainous flying.

NTSB analysis

The helicopter pilot was conducting an emergency medical services flight. He reported that, while en route to a ski resort to pick up a patient, he decided to conduct an eastbound reconnaissance over the landing site to scan for obstacles. He saw two cables in front and below the helicopter 's flightpath and initiated a go-around. He added power to clear the cables, and once the tail cleared the cables, he lowered the collective due to a slight drop in the main rotor speed. As he continued the go-around, he initiated a 180º left turn to attempt an approach to the landing site. During the westward approach and while the helicopter was about 20 ft above ground level, he raised the collective to reduce the descent rate, and the main rotor speed subsequently decayed. He felt that, due to the "faster than normal" descent rate, he would not be able to cushion the landing. Before touchdown, a medical crewmember spotted an elevated steel barrier cable below the helicopter, and the pilot made a 90º left turn to avoid a tail rotor strike. The helicopter subsequently touched down hard, bounced, rotated about 180º counterclockwise over the barrier cable, slid down an embankment, and came to rest upright.

The helicopter sustained substantial damage to the fuselage and vertical stabilizer.

The director of operations reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.

The pilot reported that, during his preflight preparation, he did not calculate the hover-in-ground-effect value, the hover out-of-ground-effect value, or the density altitude for the designated landing site. He added that the accident flight was his second flight in a high-altitude, mountainous environment and that most of his flight hours were accumulated at sea level. He was not aware that the ski resort provided an approach, landing, and takeoff procedure. He added that he should have completed the go-around and circled back around to land.

A Federal Aviation Administration inspector reported that, at the time of the accident, the density altitude for the landing site at 9,793 ft was over 12,000 ft.

Text from the NTSB. Open the NTSB docket for GAA18CA571 for the full record.