The federal report, released last month, concluded the buildings could have remained standing if not for the enormous fires that broke out after they were struck by the hijacked airplanes. The report, sponsored by the Federal Emergency Management Agency and the American Society of Civil Engineers, supports statements made on the recent NOVA special Why the Towers Fell.
But Moscatelli contends that the report's conclusions and similar expert opinions err by focusing solely on force. "You must also compare the torque, which is a physical measure of 'twist' produced by the planes with that due to the wind load the towers were designed to withstand," Moscatelli says. "Comparing the static weights of the buildings and planes is wrong. The planes were moving, and that clearly changes the problem. The buildings did not have to bear the weight of the planes; they had to stop the planes."
Moscatelli calculated that the torque applied by the planes' impact -- 7.7 million ft. tons -- actually exceeded the amount the towers were designed to resist due to wind load -- 7.4 million ft. tons. "So they could have immediately collapsed, if not for the fact that neither object is a rigid body and that the towers flexed quite a bit upon impact with the planes," he says. "If they had not at least bent temporarily, they would have been in danger of instantly toppling."
Moscatelli also determined that the 11,000 tons of force required by the towers to resist the wind barely exceeded the 7,000 tons of force required to stop the planes. "In fact, the stopping force for the plane scales as the square of its velocity, so if the plane was traveling at 564 mph these forces would be equal," he says. "This is probably why the terrorist pilots flew at such an uncommonly high speed for that aircraft, at that altitude, for that particular maneuver. They flew as if they wanted to knock them down, and I think we cannot conclude that they were so far off from doing just that."