The mystery of the crashes of the first jetliner—the Comet

 

 

The de Havilland Comet 106 was the first jet airliner to go into production and passenger service. Appearing shortly after World War II ended, it quickly became popular for its quiet and smooth flights. De Havilland hoped this Comet and larger future models would put Great Britain in the lead of international air travel. It would boost Britain’s place in the modern world, British morale, and Britain’s precarious financial situation.

However, after several months a Comet 106 crashed without apparent cause. Several months later, Comet flight 781 took off from Rome for London in January of 1954. Fishermen off the Italian coast heard an explosion overhead, then wreckage and bodies fell out of the sky. The bodies showed no sign of trauma and facial expressions gave no indication that they had warning of a problem. Because the sea was shallow, the Royal Navy salvaged the wreckage. It consisted of many smaller pieces of the aircraft’s body that gave no evidence of what caused the cabin to shatter.

Arnold Hall, a leading researcher of the British aviation industry, was given the job to gather the team and design ways to solve the causes of the crashes. The major effort was to build a box large enough to hold a Comet’s body, fill the area around the body with water, and increase the pressure inside the body as done when climbing to cruising altitude where air is thin so the body must withstand stress, then return the pressure inside the body to normal ground level. The wings were flexed as normal in flight. The process duplicated the pressures on the body of a flight from take-off to cruising to landing, while slow-motion cameras filmed the body. After several hundred “flights” a crack appeared at the edge of a window and spread, breaking the body into the small pieces found off Italy. Being submerged in water slowed the explosion. Metal fatigue and the way the body was designed and built had caused the Comet crashes.

Boeing used “rip-stop” construction—even a gash straight into the fuselage would not cause the same catastrophic decompression that had shattered the de Havilland Comet. The proof of the pudding was an Aloha Boeing 737 in 1988 lost part of the body top, as did a Southwest Boeing 737 in 2011, both flying at cruising altitude. Both landed safely with only one death.