Cases involving individuals who have been injured in crashes and collisions involving helicopters. A Helicopter Accident is an occurrence associated with the operation of an aircraft which takes place between the time any person boards the helicopter with the intention of flight and all such persons have disembarked, in which a person is fatally or seriously injured, the aircraft sustains damage or structural failure and/or the aircraft is missing or is completely inaccessible.
Keystone is an unincorporated community in central Keith County, Nebraska, United States. It lies along local roads near the North Platte River, northeast of the city of Ogallala, the county seat of Keith County. Its elevation is 3,100 feet (945 m). Although Keystone is unincorporated, it has a post office, with the ZIP code of 69144.