The corkscrew maneuver being too tight + followed directly by flying level close to the ground, these maneuvers were far beyond the ability of the pilot, and even beyond the ability of experienced pilots of a plane like that. What really makes it impossible though, is that it was going impossibly fast for that low altitude. AA77, a Boeing 757, would not be able to fly like that and stay in one piece. The same goes for the planes we all saw that hit the towers. They would have broken up much further back from their targets at the speed and altitude they were going, i.e. the wings would have come off. Boeing 757 can only reach comparable speed while flying level at a high altitude, in thinner atmosphere.