The Importance Of Hover Checks

This past week the National Transportation Safety Board (NTSB) published a report about the July 3, 2015 crash of an Airbus AS350B3e conducting Helicopter Air Ambulance (HAA) operations in Colorado. As seen in video at the base helipad, the aircraft yaws left while skids are on the ground and then continues to yaw left as the helicopter becomes airborne and goes out of camera view. The helicopter reappears as it crashes behind the site, and a post-crash fire develops almost instantly. What happened? What actions could the pilot have taken?