On March 5, 1966, BOAC Flight 911, a Boeing 707, was on a scheduled passenger service from Tokyo International Airport to Hong Kong when it faced a catastrophic failure in the air. The aircraft, after taking off, encountered severe clear-air turbulence that led to structural damage and ultimately a mid-air breakup. The flight was airborne for just a few minutes when the crew lost control, and the plane plummeted towards Mount Fuji in Japan's Honshu region. All 124 on board, including passengers and crew, perished in this tragic incident.

Clear-air turbulence is often unpredictable, occurring without any visible cues such as thunderstorms or clouds, making it particularly dangerous. Following the incident, investigations revealed that this type of turbulence could not have been avoided, as there were no reports or warnings present that could have alerted flight crews to the impending danger. The remoteness of the crash site on Mount Fuji further complicated recovery efforts, leading to delays in gathering information about the flight's final moments.

The investigation into the crash was extensive and involved multiple aviation authorities, highlighting the challenges of flight safety during the 1960s. The incident resulted in raised awareness regarding turbulence and led to changes in how weather information was communicated to pilots, improving safety protocols for future flights.