>> one of the wings, which has a winglet on it, actually sliced through the 737 wing. there was a lot of flight control systems that are damaged. it rendered the airplane incapacitated and uncontrollable, and as the 737 went out of control, of course, the aerodynamic forces actually caused it to start to break up in flight. >> everyone on board the legacy knows something bad has happened, but they don't know they've collided with another aircraft. they don't even know their plane is damaged, until joe sharkie looks out his window. >> i open my window shutter and look out, this is a sight i'll simply never forget. because i'm looking at the wing and part of it is missing. and it's a jagged bit of metal. >> they need on the ground and they need on the ground in a hurry. they need the first available airport. >> coming up, 35 heart-stopping