The conditions favoring strong lee waves suitable for soaring are : The rotor turbulence may be harmful for other small aircraft such as balloons , hang gliders and paragliders . It can even be a hazard for large aircraft ; the phenomenon is believed responsible for many aviation accidents and incidents , including the in-flight breakup of BOAC Flight 911 , a Boeing 707 , near Mt. Fuji , Japan in 1966 , and the in-flight separation of an engine on an Evergreen International Airlines Boeing 747 cargo jet near Anchorage , Alaska in 1993
BOAC Flight 911
BOAC Flight 911
Lee wave