As part of one of the world's biggest-ever aviation disasters, a passenger's camera revealed something shocking.
On 5 March 1966, British Overseas Airways Corporation flight 911, known as Speedbird 911, took off from Tokyo Haneda Airport with no problems, bound for Hong Kong.
Shortly after though, the aircraft fell out of the sky and killed all 113 passengers and 11 crew on board when it crashed in the Japanese forest.
Why did BOAC flight 911 crash?
The six-year-old Boeing 707 passenger jet was rocked violently by intense turbulence when it approached the region's iconic Mount Fuji, with the plane flying at speeds between 370mph and 425mph while approaching 16,000ft.
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It then suddenly left trails of white vapour before instantly dropping in attitude, as parts of the plane broke away.
In aviation history, it is one of the few recorded cases of turbulence that was so strong, that it managed to destroy the structure of a Boeing aircraft.
For airplane experts, the fuselage snapped in two at an altitude at 6.500ft, as the wreckage fell in the Earth in a horrific plunge to their deaths.
Falling at the forests around Mount Fuji, the plane exploded into a spectacular fireball, with wreckage being found in parts in a 10-mile area around the crash, with photos from the Japanese military revealing how scary the drop was.
The final crash report stated: "The probable cause of the accident is that the aircraft suddenly encountered abnormally severe turbulence over Gotemba City which imposed a gust load considerably in excess of the design limit."
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Despite all of this being quite chilling, what was found onboard the plane actually turned out to be a lot more horrifying.
What does the passenger footage show?
One passenger filmed the flight using an 8mm camera, and though the footage has never been made public, it contained recordings of the airport in Tokyo and views of the mountain range with Mount Fuji from above.
But investigators found that two frames were missing from the film, as footage cut back to the back of seats and the plane floor before crashing.
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According to experts, it requires a force of 7.5g for the camera to skip frames like this.
That might not mean much to you but that's about seven and a half times the force of the Earth's gravity, with G forces over 6 considered fatal over prolonged periods of time.
The missing frames signal a violent and sudden end to the lives of all of those onboard, even before the plane crashed back on land.
A 1967 edition of Flight International magazine wrote after the official crash report was released, that: "Evidence from the wreckage and from an 8mm colour film exposed by a passenger suggest that the aircraft disintegrated in a very short period of time.
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"The film sequences showed pictures of Tokyo Airport, of the Tanzawa mountains and Lake Yamanaka, followed by two empty frames, then by what appeared to be pictures of passenger seats and/or a carpet before coming suddenly to an end.
"Tests showed that a peak load of 7.5g was needed to make the film-feeding malfunction so as to skip frames in this way."
This was just one of four fatal aircraft disasters in Japan in 1966, just one day after the last.
These incidents shook public confidence in the Japanese aviation industry, leading to a sharp drop in domestic flights and airlines being forced to adapt going forwards.
Featured Image Credit: Japanese Military