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
- By Robert G. Pushkar
- Smithsonian magazine, June 2002, Subscribe
(Page 3 of 3)
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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Comments (2)
I knew Alan Johnson personally and right up to the day he passed away he was adamant that the fusalage failed where it did because of the ADF installation in the cabin roof immediately above window four. There was no ADF in the original design and he was certain that cutting the hole to fit this equipment was what led to the failures.
He is still sorely missed, a true gentleman if ever there was one.
Posted by Ian Brand on November 17,2010 | 11:34 AM
Did the Comet 4 have major problems on the inaugeral flight from London to Sydney? Was this the only Comet to fly London to Sydney?
Posted by Kevin McDonald on May 23,2008 | 05:41 AM