Originally posted by OrionStars
I am going to take the word of professional pilots, Boeing engineers, and aerospace experts over opinions of laypersons. I do that because I did study the laws and principles of aerodynamics, plus, applied those principles to real life situations - my own experiences, plus, what I can readily ascertain is and is not possible, in consideration of all factors and conditions involved - case by case.

This question of whether an amateur could have flown Flight 77 into the Pentagon was also posed to a colleague who previously worked on flight control software for Boeing airliners. Brian F. (he asked that his last name be withheld) explained, "The flight control system used on a 757 can certainly overcome any ground effect. ... That piece of software is intended to be used during low speed landings. A high speed dash at low altitude like [Flight 77] made at the Pentagon is definitely not recommended procedure ... and I don't think it's something anyone specifically designs into the software for any commercial aircraft I can think of. But the flight code is designed to be robust and keep the plane as safe as possible even in unexpected conditions like that. I'm sure the software could handle that kind of flight pattern so long as the pilot had at least basic flight training skills and didn't overcompensate too much."

Brian also consulted with a pair of commercial airline pilots who decided to try this kind of approach in a flight training simulator. Although the pilots were not sure the simulator models such scenarios with complete accuracy, they reported no significant difficulties in flying a 757 within an altitude of tens of feet at speeds between 350 and 550 mph (565 to 885 km/h) across smooth terrain. The only issue they encountered was constant warnings from the simulator about flying too fast and too low. These warnings were expected since the manufacturer does not recommend and FAA regulations prohibit flying a commercial aircraft the way Flight 77 was flown. These restrictions do not mean it is impossible for a plane to fly at those conditions but that it is extremely hazardous to do so, and safety was obviously not a concern to the terrorists on September 11. An aircraft flying at those high speeds at low altitude would also likely experience shaking due to the loads acting on it, but commercial aircraft are designed with at least a 50% safety margin to survive such extremes.

One of the pilots summarized his experiences by stating, "This whole ground effect argument is ridiculous. People need to realize that crashing a plane into a building as massive as the Pentagon is remarkably easy and takes no skill at all. Landing one on a runway safely even under the best conditions? Now that's the hard part!" While he may have been exaggerating a bit for effect, he does raise a valid point that flying skillfully and safely is much more difficult than flying as recklessly as the terrorists did on September 11.