On March 5, 1966, as the crew of BOAC Flight 911 slightly descended to 16,000 feet to give their 113 passengers a once-in-a-lifetime view of Mount Fuji, extreme clear air turbulence suddenly ripped the Boeing 707 apart in midair. None of the 124 people on board survived what is still one of the most harrowing crashes today. Meticulously evaluating the terrifying circumstances of the crash, investigators discovered the unknown and underappreciated dangers of a phenomenon we now know as mountain wave. 

BOAC Offers Around-the-World Flights During the 1960s and 1970s

British Overseas Airways Corporation (BOAC) was the British state-owned airline created in 1939 when Imperial Airways and British Airways merged. A 1971 Act of Parliament merged BOAC and British European Airways (BEA), forming today's British Airways. For most of its history its main rival was Pan Am and was Britain’s main airline outside of Europe.

While transcontinental flights did exist at the time in 1966, they did not exist in the way that we understand them today. In 1966, direct flights between faraway cities were usually not available; instead, many jetliners went on long international flight routes and made numerous stops along the way to refuel and offboard and onboard passengers. This method of travel was a model more like a sea or rail route than what we all know today to be the modern airline flight. 

And one of these such emblematic long route flights was BOAC Flight 911, a multi-day, around-the-world flight that started at Heathrow Airport in London and ended in Hong Kong, China, while making several stops around the globe including Montreal, San Francisco, Honolulu, and Tokyo. 

BOAC operated Flight 911 using a four-engine, narrow body Boeing 707, part of the first generation of Boeing’s jet airliners. The 707 was the first passenger jetliner to be put into widespread use by airlines around the world, including Pan Am, and is often credited with kicking off the Jet Age of passenger air travel. It dominated passenger air transport in the 1960s and remained common through the 1970s on domestic, transcontinental, and transatlantic flights, as well as cargo and military applications. And most of all, it established Boeing as a dominant airliner manufacturer.

Most Passengers Onboard BOAC Flight 911 Won a Seat on the Flight 

And on March 5, 1966, Flight 911 is preparing to takeoff from Haneda International Airport in Tokyo headed to its final stop in Hong Kong. The captain of Flight 911 is 45-year-old Bernard Dobson of Dorset, England, who is a veteran of WWII and has been with BOAC for nearly 20 years and had captained 707s since 1960. Joining Captain Dobson are 10 other crew. 

In addition to the crew are 113 passengers aboard Flight 911. Eighty-nine Americans are among them, and 75 of those individuals are employees or the spouses of employees of a Minneapolis, Minnesota company called Thermo King, which manufactured thermostats for automobiles. These lucky employees and their spouses were traveling on a two-week tour of Japan and Southeast Asia, sponsored by the company as a reward for good sales performances. They were seven days into their trip. 

At 1:50 p.m. local time, fully fueled and ready to go, BOAC Flight 911 pushed back from the gate at Haneda for the last leg of its journey to Hong Kong. And already we have something grim to report. You see, Flight 911 is officially one day behind its schedule. And here’s why. 

Canadian Pacific Airlines 402 Crashes 24 Hours Before BOAC Flight 911 Takes Off

The day before, Flight 911 had been forced to divert to Itazuke Air Base in Fukuoka rather than be allowed to land at its intended destination in Tokyo. Weather conditions on March 4th over that part of Japan had been rather poor with heavy fog obscuring the airport. Fortunately, conditions improved by the next day (March 5th) and in fact, the day was perfect for flying: a bright day with clear skies. A low-pressure system that had brought the bad weather to Tokyo moved off over the Pacific Ocean. 

At the same time, there is another weather phenomenon happening: high winds. Air naturally flows from areas of high pressure to areas of low pressure, creating what we know as wind — and the winds that blew over Japan on this morning were quite strong, particularly at high altitudes. The blast of cool, dry air resulted in beautifully clear weather with near perfect visibility, a welcome contrast to the previous night. After 12 noon that day, Flight 911 had arrived at its intended destination of Haneda Airport, one day behind schedule. 

While Flight 911 had safely diverted to avoid any peril caused by the weather, not all flights were as fortunate. In fact, some other flights attempted to land that night at the airport despite the bad weather. And that decision led to disaster.

Canadian Pacific Airlines Flight 402, a Douglas DC-8 arriving from Hong Kong on the first leg of a flight to Vancouver, had been holding over the airport for some time. Just as the captain considered diverting to Taiwan, air traffic control informed the crew that conditions had improved above the legal minimums. While approaching the airport around 8 p.m. in darkness and fog, the DC-8 descended below the glide slope and struck the runway approach lighting system. The plane continued forward, plowing into a seawall before crashing onto the runway in flames. In the impact and subsequent fire, 64 of the 72 people on board were killed. 

By the time that BOAC Flight 911 is taxiing down the runway preparing for takeoff the next day, it passes by the still smoldering remains of Flight 402. In fact, video footage exists that shows Flight 911 taxiing past the wreckage on the airport runway, linked in episode links. 

It must have been surreal for the passengers of Flight 911 to see the charred bones of Flight 402 where 64 people had just burned to death less than 24 hours before. It's hard not to imagine some of the passengers on BOAC Flight 911 looking out the windows as their plane taxied down the runway, seeing the wreckage, and thanking their lucky stars they weren't on that flight. Several of the Thermo King passengers had even sent messages back home or made last-minute calls reassuring their loved ones they hadn't been on that flight. 

It is also important to note that 1966 was a particularly bad year for Japanese aviation. Just one month prior, on the night of February 4th, All Nippon Airlines Flight 60 had abruptly crashed into Tokyo Bay while approaching Haneda Airport. All 133 passengers on board that 727 were killed in what was at the time the world's worst single plane aviation disaster, and the cause for the plane taking a sudden dive into the bay was never determined. 

But despite any disturbances anyone onboard might have felt as the plane taxied past the wreckage of Flight 407, it likely mattered no more as soon as Flight 911 accelerated down the runway and lifted off at 1:58 p.m. 

BOAC Flight 911 Pilots Get Closer to Mt. Fuji Giving Passengers a Better View 

One of the main reasons why passengers booked a seat on Flight 911 was to see the amazing sites as the plane flew overhead. One of the American passengers had a window seat and was one of the lucky few to have movie camera – and as we’d expect, it was rolling. The silent film included shots of the airport terminal before boarding, then the cameraperson started shooting again as the plane climbed out of Tokyo, taking in sweeping vistas of the mountains looming in the distance. 

In the cockpit, the pilots leveled out at about 17,000 feet (or 5200 m), in the direction of Mount Fuji, and then began a short descent toward 16,000 feet (or 4800 m) to do something we have heard pilots do on so many other sightseeing flights we’ve covered on Take to the Sky – they wanted to give their passengers the best view of Mount Fuji as possible. 

A character that looms large in this story is the volcanic mountain itself, so let’s talk about Mount Fuji. The mountain rises to a height of over 12,000 feet (3700 m) in just a few kilometers, making it one of the world’s steepest and most symmetrical peaks. As the tallest mountain in Japan, its height and its isolation from other mountains meant that it jutted up into the stream of wind blowing over the islands from west to east. As we mentioned, this day brought bright blue skies but also very high winds across that area of Japan. In fact, meteorologists at a weather station on the summit of the volcano clocked sustained wind speeds that day more than 110 kph (or 68 mph). 

Beneath each crest of the wind's current there is sometimes a rotating air mass, and these "rotors," are small but intense whirlwinds shaped like a tornado lying on its side. In clear, dry weather, just like the day of our story, this chain of rotors is utterly invisible and can be encountered without warning. This phenomenon is now known as mountain wave. In 1958, in the first research project to document the mountain wind waves, a research plane was destroyed in a severe rotor. The pilot bailed out and survived. Very little else had been studied or was known at the time about mountain wave. 

All the planes that flew near Mt. Fuji on March 5th reported heavy turbulence, but that was nothing out of the ordinary and certainly nothing that could endanger a jetliner the size of a 707. And as the pilots of Flight 911 descended gradually toward 16,000 feet, to ensure their customers got the best view possible, the pilots were likely prepared to encounter invisible clear air turbulence. But what awaited them was something far more vicious than anything a jet had flown into before. And the pilots as well as the aircraft stood zero chance of escape. 

BOAC Flight 911 Blasted with Mountain Wave, Causing Inflight Breakup

An enormous gust of wind blasted the plane, bringing with it a gravitational load of more than +7.5Gs, which is on par with the force and power of a rocket ship reentering Earth’s atmosphere. The shock of this load would have sent any passengers inside the plane who were not buckled down flying into the ceiling and floors as they plane buffeted in extreme ways – and would have probably killed them on impact. But that was only the beginning. The power of this gust was so enormous that the plane’s structural integrity gave could not hold out. 

As the gust enveloped the fuselage, it first ripped off the plane’s tailfin, and as the tailfin broke away, it smashed against the left horizontal stabilizer. These parts are essential to a pilot being able to control a plane – the tailfin holds the stabilizers to the plane and the horizontal stabilizer prevents an up-and-down motion of the nose. The left stabilizer then also broke away, causing the plane to pitch steeply upward for a fraction of a second. The sudden pitch-up of the plane put such a stress on all four engine pylons, which are the links that connect the engines to each part of the wing, that the engines completely and instantly broke apart from the wings. And when the engines broke away, the force split the plane’s cabin apart, from the tip of the cockpit all the way through to the first several rows of passenger seats. It’s like taking a stick and breaking it against your leg – it snapped apart. And in the blazing, clear blue sky, witnesses saw people falling out of the bisected plane, accompanied by a rush of clothes and other items that streamed out from the passengers’ luggage or off their falling bodies. 

Witnesses on the ground also caught sight of the plane falling as its structure was ravaged by the forces imposed upon it – many onlookers saw trailing white vapors as fuel spirted from the plane and falling debris. The airliner began to plunge from the sky in a flat spin, falling like a leaf as it spun around over and over. People on the ground snapped photographs of the jet corkscrewing downward from 16,000 feet, capturing its final death spiral. 

No firsthand accounts remain of what passengers experienced, but we do understand the effects of g-forces on the body. According to SOFREP.com, at 7Gs, your body is immediately in pain. Not only does your body feel like it is being smothered by really heavy weights, but every inch of your body feels as if it is under a vise. The pain is at an overbearing level and all the blood vessels and capillaries in your skin would begin to burst under the massive strain.

Your face begins to droop as if your cheeks are being stretched down to your shoulders. And all these physical effects would happen just three to four seconds in, but the more force you sustain, the worse it gets. 

Your body wants to quit and pass out as all the blood is now draining from your head. It’s nearly impossible to breathe. Your pulse skyrockets as your heart attempts to keep blood pumping to the brain. Color drains from the visual world and it is like watching a black and white movie. But this is not a movie – this would have been the last minutes of peoples’ live. 

After everything goes black and white, the tunnel vision begins. A dark circle encroaches your vision, starting in the periphery, and slowly constricting what you can see. The circle begins to shrink further and further until everything is black. The only consolation is that most people would have passed out rather quickly. 

Minutes after it first begin tearing apart, the scattered wreckage of BOAC Flight 911 finally crashed on the slopes of Mount Fuji, destroying what remained of the plane and killing all 124 people in the process. 

There are official accounts of the causes of death of many passengers mentioned in official wires sent back to families in the US from Tokyo following the crash: blunt force trauma to multiple body parts. This is evidence that many of them might have been unconscious but certainly not already dead as they plummeted to earth. 

Japanese Investigators Examine Onboard Camera Footage of Crashed BOAC Flight 911 Plane

When rescuers arrive, they discover a massive crash scene, with a debris field that stretched more than 16 kilometers long (3.7 miles), trailing from the town of Gotemba all the way to the resting place of the main fuselage. The cockpit was found nearby, having been consumed by fire upon impact. This proved to be a major setback to the investigation, because in the earliest models of the 707, the flight data recorder was in the cockpit, and the fire had rendered it unreadable. And to make matters worse, at that time, jets were not required to carry a cockpit voice recorder, and so none was installed on Flight 911.

As news of the crash made its way around the world, the people of Japan, America, and Britain wanted answers. Not only was this the second fatal crash near Tokyo in 24 hours, but it was also the fourth fatal crash near Tokyo in the past 30 days. So far, investigators had not determined the cause of any of these accidents, and at first it seemed like BOAC Flight 911 might meet the same fate. And remember, the majority of passengers are American, so the United States also has a vested interest in finding out how so many of its citizens perished in this awful crash. And, at the time of the crash, there was a lot of speculation ranging from a missile to inflight fire. 

Investigators are certainly challenged by not having any flight data recorders, so they use the evidence that is available to them. And where they begin with that evidence is in an unexpected place and by using a method rarely seen in crash investigations: reviewing the video footage shot by the passenger on board the doomed plane. Because the fuselage didn’t catch fire, the film survived the impact and was able to be developed. 

To this day, only investigators have seen this footage. But according to a post on Reddit and very early news accounts just days following the crash, the film allegedly showed the mountain and countryside at the beginning of the flight and into the initial ascent. Then, something jars the camera and skips over the next two frames, and then it shows pictures of the seatback and floor carpeting. The video camera, which was recording at the moment of the upset, malfunctioned, and skipped two frames under the massive G-load, then briefly captured blurred images of the cabin interior before it abruptly stopped filming. 

Tests on the camera showed that to get the camera to skip two frames, it had to be subjected to a load of at least 7.5Gs. This amount of force was easily enough to rip the tailfin off a big jet airliner. And based on its position in the wreckage trail, the tailfin was the first part to come off. From there, following the distribution of the debris, some understanding of the sequence of the breakup could be developed. 

Investigators Explore Mountain Wave as Possible Cause of BOAC 911 Crash

Though investigators now confirm that something suddenly and violently brought the plane down and caused a midair breakup, investigators needed to understand why. And that answer came from a lucky break in the form of a close call that another aircraft had near Mount Fuji that same day.

On the day of the crash, a US Navy Skyhawk participating in search and rescue efforts for Flight 911 flew into the exact same mountain wave that brought down the 707. Despite encountering wild load fluctuations ranging from -4 to +9Gs, the pilot managed to regain control and survived to tell the tale. 

Using this account as evidence of clear air turbulence, Japanese investigators set up a scale model of the terrain around Mount Fuji and ran wind tunnel tests to determine what kind of turbulence might have existed on the lee side of the volcano. They found that strong winds blowing over the cone created an area of unstable air extending up to 20km (or 12 miles) in the wake of the mountain, as well as upward from the summit to an altitude of 16,000 feet. 

An airplane of the size of a 707 can easily handle a 100-kph (or 62 mph) horizontal wind because it is not much different from the normal aerodynamic forces experienced in flight. But a vertical wind of equivalent strength is extremely rare, and a plane designed to withstand horizontal wind loads may not be able to withstand those same loads from a different direction.  What this means is that a 100-kph vertical gust could easily tear an airplane apart. And that is how fast the winds were blowing at the time that Flight 911 was headed toward the mountain. 

It became clear to investigators that from the moment the plane encountered the mountain wave, disaster was inevitable. It seemed that a classic Japanese proverb spoke truth about the fate of the plane: “When the sky is blue, Fuji is angry.” The pilots never stood a chance. 

Here is the heartbreaking legacy of not understanding something before it happens: had the crew stuck to their filed flight plan and remained at 17,000 feet instead of trying to take their passengers sightseeing, they never would have strayed close enough to Mount Fuji to be impacted by the rotors. 

The Legacy of BOAC 911 Crash

Flight 911 was only one of many crashes that occurred due to sightseeing detours. Previous to this crash, we discussed episode 7, the Grand Canyon Midair Collision of 1956, which was borne out of the same good intentions of veering from a flight path to show passengers a great view. But by the start of the 1970s, both safety concerns and the need to balance sightseeing with profit put an end to any sightseeing that was not on a plane’s direct flight path. 

At the time, mountain wave phenomenon was not well understood. It was difficult to accurately model the complex airflow patterns and find the real strength of the turbulence created by different mountains and wind directions. But for airline pilots, BOAC Flight 911 provided a simple lesson: when the wind is blowing, stay away from high mountains. 

Though understanding the effects of mountain wave is the true legacy of Flight 911, the investigative conclusions were not as straightforward. According to blog accounts for this story, the Japanese investigation made no safety recommendations relating to mountain waves or clear air turbulence, apparently writing off the encounter as an act of god. The only recommendations made in its final report concerned fatigue cracks found in the plane’s tail, a discovery which proved unrelated to the disaster. A copy of the final accident report with recommendations could not be located by the date of this recording. 

Thanks to this terrible disaster, pilots better understand mountain wave and meteorologists can issue SIGMETs related to high winds surrounding mountains so that pilots can take evasive actions and avoid the mountains. Mountain waves will mostly today only bring down small planes, but the phenomenon was thought to have caused a crash of United Airlines Flight 585 in 1991 outside of Colorado Spring, Colorado in the US. Early reports following the crash said that rotors near the base of the mountains were to blame, though the final report said whether that caused the rudder hard over, which is what ultimately caused the fatal crash. No other major commercial crash on record has been definitively brought down by mountain wave since Flight 911. 

Sixty-three Children Orphaned From BOAC 911 Crash 

There were 124 people onboard Flight 911, and the ripple effects of the disaster would last for a generation. Sixty-three children were orphaned because of the deaths of so many parents. 

And here is just one of the families’ stories. According to an archived newspaper article from 1966, Karol and Elsie Kawa had called Elsie’s sister to reassure her sister they were not aboard the Canadian airliner which crashed earlier in the day at Tokyo International Airport, killing 64 persons. Elsie’s sister was caring for their children, ranging in age from 8 to 13. 

Then the Kawas boarded BOAC Flight 911 just thirty minutes after that phone call. Several hours later, the phone rang again. It was officials informing them of the second crash, this time of Flight 911. Else knew immediately what had just happened: the Kawas won that trip from the Thermo King Corporation of Minneapolis which sponsored the tour. The Kawas’ three children were among those 63 children orphaned from the crash. 

A memorial has been erected near the crash site in a quiet section of forest. Based on the pictures, if you came upon it, you would not likely know what it was for, as no explanation of the crash nor names of the victims appear. The monument stands in quiet contrast to the violent deaths suffered by all on board. 

James Bond Movie Team Changed Flight Last Minute from BOAC Flight 911

An odd piece of pop culture trivia is also attached to this crash. There were some would-be passengers who luckily, at the last minute, cancelled their tickets for this flight. They were movie producers Albert R. Broccoli and Harry Saltzman, production designer Ken Adam, director Lewis Gilbert, and cinematographer Freddie Young. The five men decided last minute to attend a live Ninja demonstration, and as they were location scouting for a film, thought it was important enough to see as it might be a good location for the film. And ironically, the film was the James Bond film, “You Only Live Twice.” 

And THAT is the story of British Overseas Airways Corporation Flight 911.