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Comet's Tale

A half century ago, the first jet airliner delighted passengers with swift, smooth flights until a fatal structural flaw doomed its glory

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The throng of spectators, including famed airplane designer Sir Geoffrsey de Havilland, heard the earsplitting shriek before they saw the sleek, bullet-shaped aircraft burst out of the mist and hurtle down the runway at LondonAirport. The Comet 1 airliner roared into the air— and into history—on 20,000 pounds of thrust from its four De Havilland Ghost jet engines. For the first time ever, a jet-propelled aircraft was carrying passengers over a scheduled commercial route.

It was Saturday, May 2, 1952. On board were 36 passengers, six crew members and 30 bags of mail. At the Comet’s controls, British Overseas Airways Capt. Michael Majendie headed the jet toward Rome, the first of five stops on the 6,724-mile journey to Johannesburg, South Africa. The plane smoothly accelerated to a cruising altitude of 35,000 feet and a speed of 460 miles per hour, more than 100 miles per hour faster than the fastest propeller-driven airliner. Suddenly, the world was a smaller place.

Less than 24 hours later, thousands more onlookers ringed Johannesburg’s PalmieterfonteinAirport as the Comet 1—registration G-ALYP, dubbed “Yoke Peter,” from the phonetic alphabet then in use in Britain (George-Able- Love-Yoke-Peter)—streaked into view. Capt. R. C. Alabaster, now 84, who flew the last three legs of the flight from Khartoum, remembers the scene vividly. “Oddly enough, as we circled the airport we could see all these cars and people blocking the roads, and we thought it just must be busy. It wasn’t until after we landed that we learned they had come to see us.”

Comet flight engineer Alan Johnson, now 83, who had flown many test flights, says, “This trip was the hardest because we had to make sure we got into Jo’burg on time and out the next day. By then I was quite used to crowds wherever we flew.”

Though aubrey cookman, an editor at popular Mechanics magazine, found the plane noisier than he had expected, he told reporters that his only regret was that the United States wouldn’t have anything like the Comet for several years. He was right: the British were far ahead of the United States in the development of passenger jets.

The revolutionary planes could be traced to World War II, when a group of visionaries, led by Lord Brabazon of Tara (often called the father of British aviation), convened to study Great Britain’s postwar position in commercial aviation. The committee was haunted by the knowledge that by 1939, the American twin-engine Douglas DC-3 was carrying a staggering 90 percent of the world’s airline passengers. America ruled the skies and looked poised to continue to do so. In the war years, the much bigger and faster Douglas DC-4 and the Lockheed Constellation 649 took to the air, ready to jump into commercial service as soon as the war ended.

Brabazon’s group knew that the noise and vibration of propeller-driven planes were significant fatigue factors for passengers on long-distance flights, as four behemoth 18- cylinder engines responded to thousands of gasoline-fueled explosions per minute. Such engines required complex supercharging— forced compression of air into the cylinders— to cruise efficiently at high altitudes, above bumpy and hazardous weather. Though the big piston engines werecrafted with skill and precision, they simply could not be made to run smoothly, nor could they be easily made more powerful than they already were.

The committee was also aware that jet engines, invented independently before the war by both English and German experimenters, were virtually vibration-free. Furthermore, jets were at home at high speeds and high altitude. If the British could parlay their lead in jet-engine technology into a new airliner, they might be able to break America’s choke hold on commercial airline sales.

By war’s end, only one British manufacturer—De Havilland— had built a jet engine and designed a plane for it. With the blessing of Britain’s Ministry of Supply and working under a cloak of secrecy, Sir Geoffrey accepted the challenge of creating a commercial jet airliner.

A major problem for the designers was fuel consumption, which was at least three times greater for jets than for piston engines, especially at low altitudes. Kerosene was the fuel, and 1945-vintage turbojet engines consumed it three to four times as fast at 10,000 feet as at 30,000. Sir Geoffrey reasoned that a plane could fly more efficiently at 35,000 feet, where the air was thinner and less power would be required for propulsion.

Such high-flying planes, though, would need a pressurized cabin to allow passengers to breathe without oxygen masks. Pressurization would mean that as the airliner climbed to its cruising altitude nearly seven miles above the earth, the cabin would have to be pumped with air until its interior pressure exceeded the pressure outside the fuselage by about five pounds per square inch. As the plane descended to land, cabin pressure would have to be bled off again. Each cycle would put enormous stress on the plane’s structure; the tubular cabin would stretch slightly when pressurized, then contract as pressure was released.

Just three years after full-fledged design work commenced, De Havilland chief test pilot John Cunningham lifted the Comet off the ground for the first time and pronounced the plane “Very promising. Very quick.” Joining him as test pilots were Michael Majendie and Ernest Rodley, now 87, who became the world’s first certified commercial jet pilot. “I was able to get down to the Ministry of Aviation in London to get my license endorsed first,” says Rodley. “That’s the only reason I’ve achieved fame.” Of Majendie, an expert in flight planning, he says, “He was the brains, and I was the experience. Together we made quite a little team.”

The British Overseas Airways Corporation ordered eight of the airliners, and as word spread, other airlines came knocking on De Havilland’s door. Only one U.S. carrier, Pan Am, placed an order, for three larger, longer-range Comet 3s, which were still on the drawing board. For the most part, the American airline industry—then highly profitable with its existing propeller-driven fleets—had little interest in spending huge amounts of money for untried, fuel-guzzling jets.

In only its first year, the Comet flew 104.6 million miles, carrying 28,000 passengers. Then, on October 26, 1952, a Comet leaving Rome ran off the runway and skidded to a halt with a broken landing gear. The 35 passengers and eight crew members survived. Five months later, a Canadian Pacific Comet bound from London to Sydney crashed on takeoff at Karachi, Pakistan, and burned, killing all 11 passengers and the crew. An investigation revealed a flaw in wing configuration. Revised pilot instructions and a change in the wings’ leading edges solved the problem.

Then, two months later, a year to the day after the inaugural flight, a BOAC Comet with 43 passengers and crew disintegrated at 10,000 feet after leaving Calcutta in a heavy thunderstorm. Eight months after that, on January 10, 1954, something went terribly wrong at 26,000 feet on a BOAC flight a few minutes out of Rome. “I heard a roar, very high,” police quoted one eyewitness as telling them. “Then there was a series of blasts. The next thing I saw was a streak of smoke plunging perpendicularly into the sea.” The plane, the inaugural Yoke Peter, carried 29 passengers and a crew of six.

The next day, BOAC grounded all Comet flights. “Initially, we didn’t think it could be mechanical breakup,” says Captain Alabaster. “We had every confidence in the airplane.” Adds Ernest Rodley: “It was a perfect airplane as far as we were concerned. We were absolutely puzzled by the problems.” The Ministry of Civil Aviation launched the largest aircraft accident investigation ever undertaken at the time, and the British Admiralty started a salvage operation— no easy task, given that the plane had gone down in 500 feet of water.

Within a month, the navy had brought up a big section of Yoke Peter’s tail, along with skin from the fuselage and miscellaneous other parts. The wreckage was taken to the Royal Aircraft Establishment at Farnborough, England, for scrutiny by scientists and engineers. After investigators concluded that “there appeared to be no justification for placing special restrictions on the Comet aircraft,” the planes began flying again. Public confidence remained high; every seat on the first resumed flight was filled. But on April 8, even as Yoke Peter’s remains were still being assembled at Farnborough, a South African Airways Comet on a flight from Rome to Cairo lost radio contact at 35,500 feet and fell into the Mediterranean. Fourteen passengers and seven crew members were lost. Comets were immediately grounded for the second time in three months.

Prime Minister Winston Churchill now intervened. “The cost of solving the Comet mystery must be reckoned in neither money nor manpower,” he declared. At stake were no less than the credibility of the British aircraft industry and the viability of jet aircraft worldwide.

Yoke Peter’s reassembled pieces pointed to metal fatigue. But why? Pressurization was the leading suspect. Says Captain Rodley, who took part in the inquiry: “No one had taken into consideration the pressurizing cycles on the fuselage for a given time span, which were faster than the equivalent cycles in the slower, propeller-driven airplanes.” To gauge the effect of these cycles, an entire Comet fuselage was placed in a giant water tank, and its sealed interior filled with water. To simulate cabin-pressure changes in an aircraft climbing to 35,000 feet and then descending again, interior pressure was increased and decreased at three-minute intervals. Around-the-clock testing aged the Comet nearly 40 times faster than actual service.

In the meantime, autopsy reports from the Italian pathologist who examined the bodies of victims of one of the crashes indicated they had died “by violent movement and explosive decompression.” Evidence pointed to the catastrophic failure of the fuselage. The final clue, revealing the weakness in the Comet’s structure, turned up on June 24 in the tank at Farnborough, where the immersed test Comet had been subjected to the equivalent of 9,000 flying hours. Instruments showed a sudden drop in cabin pressure, indicating that something had happened in the tank.

When the drains were opened and the water flooded out, scientists stared in grim amazement. Repeated pressurization had caused the fuselage to split. One fracture started in the corner of a window atop the aircraft where radio aerials were housed and continued for eight feet, passing directly through a window frame in its path. Closer examination showed discoloration and crystallization, telltale evidence of metal fatigue. At high altitude, after many pressurization cycles, the Comets’ fuselages simply lost their ability to contain high air pressure, and the planes exploded with bomblike force.

After the investigation, the Comet 1’s future was sealed. It never carried another passenger. Neither did its wouldbe successors, Comets 2 and 3. Comet 4 was four years in production, and by the time it went into service it had been overtaken by developments in the United States. Fewer than 70 were ever built for airline service.

On July 15, 1954, test pilot Tex Johnston lifted the creamand- buff Boeing 367-80 (the famous “Dash-80,” now in the collection of the Smithsonian’s National Air and SpaceMuseum) off the runway at Renton, Washington. It was the first flight of what would become a new jet airliner, the Boeing 707, with more than three times the passenger capacity of the Comet 1. It would enter service in 1958, at the same time as the much smaller Comet 4. In all, eight hundred and fifty-five 707s would roll off Boeing’s assembly lines. The United States had entered the jet age, where it would maintain its dominance into the 21st century.

Still, Boeing had not gotten there first. That honor went to De Havilland and the Comet, which had made a shrinking world even smaller, changing forever the way its people traveled the globe.

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