What happened
On September 29, 2018, a Eurocopter AS3pend350 (registration N894NA) was en route to a ski resort in Ruidoso, New Mexico, to pick up a patient. While conducting an eastbound reconnaissance of the landing site, the pilot identified two cables in the flight path and initiated a go-around. To clear the cables, the pilot added power; however, after the tail cleared the obstacles, the pilot lowered the collective due to a slight drop in main rotor speed.
As the pilot attempted a 180-degree left turn to approach the landing site from the west, the aircraft was approximately 20 feet above the ground. When the pilot raised the collective to reduce the descent rate, the main rotor speed decayed. The pilot noted a descent rate that was faster than normal, making it difficult to cushion the landing. During the final moments before touchdown, a medical crew member identified an elevated steel barrier cable below the aircraft. The pilot executed an additional 90-degree left turn to avoid a tail rotor strike.
The helicopter touched down hard, bounced, and rotated approximately 180 degrees counterclockwise over the barrier cable. The aircraft then slid down an embankment before coming to rest upright. There were no injuries resulting from the accident, but the helicopter sustained substantial damage to the vertical stabilizer and fuselage.
Findings
An investigation into the flight revealed several contributing factors regarding performance and preparation:
- The pilot did not calculate the density altitude, hover in ground effect (HIGE), or hover out of ground effect (HOGE) values for the landing site during preflight.
- At the time of the accident, the landing site elevation was 9,793 feet, with a density altitude exceeding 12,000 feet.
- The pilot had limited experience in high-altitude, mountainous environments, as most of his flight hours were accumulated at sea level in Texas.
- The pilot was unaware that the ski resort had established specific approach, landing, and takeoff procedures.
- The operator was unaware that dedicated procedures existed for helicopter medical evacuations.
- The crew lacked sufficient crew resource management (CRM) skills and procedures, and there was no performance or destination briefing conducted prior to the flight.
- There were no mechanical failures or malfunctions identified that would have prevented normal operation.