your liying with your numbers. your comparing the 707-320B with the recent boeing models. but the wtc was designed to take a 707-020 hit. the 707-020 weighed 222,000 lbs full and 103,145 lbs empty a hell of a lesser weight than the 707-320B which came in at 333,600 lbs full and 146,400 empty. so your comparative calculations are crap.