Seattle Times: Twin Towers Engineered To Withstand 707 Jet Collision – Chief Engineer John Skilling

Twin Towers Engineered To Withstand Jet Collision

Feb 27, 1993

Eric Nalder

Engineers had to consider every peril they could imagine when they designed the World Trade Center three decades ago because, at the time, the twin towers were of unprecedented size for structures made of steel and glass.

“We looked at every possible thing we could think of that could happen to the buildings, even to the extent of an airplane hitting the side,” said John Skilling, head structural engineer. “However, back in those days people didn’t think about terrorists very much.”

Skilling, based in Seattle, is among the world’s top structural engineers. He is responsible for much of Seattle’s downtown skyline and for several of the world’s tallest structures, including the Trade Center.

Concerned because of a case where an airplane hit the Empire State Building, Skilling’s people did an analysis that showed the towers would withstand the impact of a Boeing 707.

“Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire. A lot of people would be killed,” he said. “The building structure would still be there.”

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