The Comet, the 707, and the disaster that shaped the Jet Age

In 1952, Britain won the race to put the world's first jet airliner into service by a comfortable margin, but it turned out to be a hollow victory. Disasters, delays, and an unlikely rival from across the Atlantic upended British ambitions and reshaped the early years of the Jet Age.

On Saturday, May 2, 1952, the world's first jetliner service began commercial operations when a British Overseas Airways Corporation (BOAC) De Havilland Comet passenger jet, registration G-ALYP, took off from the tarmac of London Airport on the first leg of the journey to Johannesburg, South Africa.

Onboard the aircraft were a crew of six, 36 passengers, and 30 bags of mail, all set for a 6,724-mile (10,821-km) journey requiring five stops to complete. Crowds of onlookers and newsreel cameras showed up to see the new aircraft in action. This wasn't a piston-engined passenger liner like the Lockheed Constellation, this was a jetliner that took off with a roar as the four Ghost engines embedded in its wings powered up and thrust it 35,000 ft (10,000 m) into the air at a phenomenal rate of climb for a commercial flight.

Once airborne, the Comet headed south at 460 mph (740 km/h), or 100 mph faster than the fastest propeller-driven airliner. Inside the pressurized cabin, the passengers traveled in relative luxury, with large windows, reclining "slumber seats," and a proper galley serving hot meals and cocktails. It even felt more relaxed, because the jets did away with the noise and vibration piston engines could never escape.

In all, the Comet seemed like a real victory for postwar Britain.

In 1939, the American twin-engine Douglas DC-3 carried 90 percent of the world’s airline passengers and US aircraft manufacturers seemed certain to dominate the passenger plane market as they shifted from wartime to commercial production. However, Britain had some of the best aeronautical engineers in the world and the ace up its sleeve having, independently of Germany, invented the jet engine. If this advantage could be exploited, then Britain could steal a march on the Americans and break their near-monopoly by way of a technological quantum leap.

With the support of the Ministry of Supply, De Havilland, the only British company capable of the task, set about designing and building a jet airliner in the last years of the 1940s. This wasn't just a matter of slapping a jet engine into a prop plane and hoping for the best. De Havilland's engineers were moving into unknown territory as they developed both the engines and the aircraft they would fit in at the same time.

The project required all sorts of innovations, such as a pressurized hull because the craft had to fly at high altitude to be efficient. The aerodynamics meant swept wings. New avionics, control systems, safety features, alloys, plastics, and other materials had to be invented. On top of all this, the aircraft, now called the Comet, was an entirely new class and that meant some of the most extensive certification testing ever required.

The result was an aircraft smaller than many airliners already in service, which carried fewer passengers. But it had a much faster cruising speed of 460 mph and a range of 1,500 miles (2,400 km). It could also turn a profit when only loaded to 43 percent capacity, and could fly from London to Tokyo in only 36 hours instead of 86.

In other words, it suddenly made the world a lot smaller.

Though it flew mainly with BOAC, the Comet was extremely popular and carried over 30,000 passengers during its first year of operation. It seemed like De Havilland would soon have more orders than it knew what to do with from airlines around the world and Britain's balance of payments would push toward the black as exports of Comets and their service contracts soared.

Then disaster struck.

Three Comets crashed in 1952 and 1953, but these were due to broken landing gear, a slight design flaw, and bad weather – nothing out of the ordinary for any plane, especially a new one. This changed on January 10, 1954, when G-ALYP took off from Rome and seemed to fall apart in midair, crashing into the Mediterranean off the coast of Elba.

The Ministry of Civil Aviation briefly grounded the Comet fleet and began an investigation, and the Royal Navy started a salvage operation. A few months later things got even worse. On April 8, 1954, another Comet, G-ALYY, which was en route from Rome to Cairo and then on to Johannesburg, fell apart in the same way.

All the Comets were grounded again and a massive investigation was mounted as to the cause of the crash. What could be recovered from the craft was reassembled by the Royal Aircraft Establishment (RAE) and a duplicate Comet was subjected to stress tests using jacks to simulate vibrations and a giant water tank for hull pressure tests.

The engineers found the designers didn't have a good enough understanding of the kind of metal fatigue the jet airframe underwent. As the aircraft flew to high altitudes and back to the ground, the pressurizing and depressurizing placed repeated stress on the hull, and the hull framings weren't strong enough. As a result, cracks formed at key areas, such as a radio antenna fitting and a cargo door, and after about 1,000 pressure cycles the hull gave way and the jetliner exploded like a bomb.

As a side note, one myth that arose was that the Comets crashed because they had square windows instead of round. While high stress was found at the window corners, these were not the source of the hull failure.

The upshot of this was that the first-generation Comets were pulled from service. Because the basic design was judged to be perfectly sound, modifications were made and Comet variants 2, 3, and 4 went into production.

Unfortunately, it was too little too late. De Havilland lost over four years because of the accidents and the public lost confidence in the Comet. Sales plummeted. Only 70 Comets went into service, with another 16 built for the RAF, some of which became the famous Nimrod marine patrol aircraft that flew until 2011.

Boeing takes off

Meanwhile, in the United States, an unlikely contender entered the contest to build a jetliner.

Seattle-based Boeing was a successful company, but it was known mainly as a builder of military aircraft like the B-29 Superfortress bomber, not passenger planes. The smart money was on Douglas and Lockheed, with Boeing's 377 Stratocruiser hitting the market like a lead balloon.

In 1954, Boeing rolled out the 367-80 "Dash 80" quadjet prototype aircraft it was marketing as a military transport and tanker. Equipped with the same Pratt & Whitney JT3C turbojet engines that were used on the B-52 Stratofortress, the Boeing engineers realized that they had a lot of power on their hands. It was enough to warrant designing a passenger version of the Dash 80 with a wider hull that would seat six passengers abreast and could reach a speed of 550 mph (885 km/h). It was also tough enough to do a barrel roll, which a Boeing test pilot executed over Lake Washington in August 1955 with the Dash 80 prototype.

Clearly brimming with confidence, Boeing bet more money than the company was worth on this new jetliner.

The end product was the first of Boeing's 700 series, the Boeing 707, which made its first production flight on December 20, 1957. It had a wingspan of 131 ft (40 m), a cruising speed of 600 mph (970 km/h), a range of 3,000 miles (4,800 km), and could carry 181 passengers, putting it in an entirely different league to the struggling Comet.

The strongest competitor to the 707 was the Douglas DC-8. Douglas was well established with the airlines and was confident enough to wait for the development of new jet engines before designing its new, larger airliner. But Boeing stole a march by redesigning the 707 for greater payload and range, as well as being open to clients who wanted their own variations, like long-range models for Qantas Airways of Australia and larger engine variants for Braniff’s high-altitude South American routes over the Andes. The company even spent US$15 million on noise suppressors and thrust reversers to make the plane friendlier to airports.

With the Comet disasters in mind, Boeing even subjected the 707 to a very public “guillotine test” where a 707 fuselage was hit with five giant blades. The only damage was that the hull leaked air – no cracking or exploding.

All this paid off on October 13, 1955 when Pan Am ordered 20 of the 707s for its fleet, along with 25 Douglas DC-8s. Boeing then got Pan Am to buy another 50 by offering to make the 707 a half-inch wider. Then BOAC put in an order for the 707 as a successor to the Comet and orders came in from TWA, Qantas, and other airlines. Very soon the 707 boomed in popularity to the point where it outsold the DC-8. Airports and air traffic systems were soon upgraded to accommodate it.

By 1978, over a thousand 707s were built for the civilian market, while 800 were built for the military by 1990.

With the success of the 707, air travel entered a new age of glamorous, wealthy Jet Setters having breakfast in New York and dinner in Rome. Airlines now had the right measure of speed, comfort and even opulence, emphasizing cabin service and making air travel a status symbol for the elite that would continue into the age of the Concorde.

Boeing claimed the prize that had been dashed from the grip of De Havilland but, ironically, the Comet is what made the 707 possible. Not only did it introduce many passenger air travel technologies and set the pattern for cabin service, it also encountered the disasters, and the lessons they taught, first.

As to the 707, it became a victim of its own success. It triggered a boom in air travel that swept aside the North American railways and the great Atlantic passenger ships, but it caused such a rise in passenger demand that it was soon seen as too small for the job, so it had to give way to another Boeing plane, the 747 Jumbo Jet, as the Jet Setters gave way to the economy class flyers, and cabin service gave way to box lunches.