"It's more likely that lightning would cause a fire or punch a hole through the aircraft structure, " he said.

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All things being equal, which they rarely are, the higher the cyclical stress level on an aircraft structure, the fewer the number of reversals it can withstand before breaking.

ECONOMIST: Aircraft fatigue

What makes aircraft fatigue such an dark art is that, unlike standard tests done in a laboratory, an aircraft's structure has to endure a complex, mostly random, set of static as well as cyclical stresses when in service.

ECONOMIST: Aircraft fatigue

Training doesn't just involve teaching someone how to structure an aircraft loan, write nifty software or even hew to company policies.

FORBES: To Train Or Not To Train?

Still assuming a much smaller, light aircraft had hit the structure, the group emerged from the tower and were directed by policemen to keep moving.

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The low-slung structure, surrounded by a black iron fence, was once an aircraft parts factory.

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