>> right then and there i knew that this was going to be the worst day of my life as a firefighter. >> go to the world trade center. >> immediately i knew this wasn't an accident. >> oh, my god. that looked like a direct impact. >> chief pfeifer made the first official report. >> we have a number of floors on fire. it looked like the plane was aiming towards the building. third alarm. we'll have the staging area. bessie and west street. >> everyone he was passing was looking up. it was like the world just stopped. >> we're getting a look at the world trade center. we have something that has happened here, a plane and a lot of smoke from one of the towers. whatever has occurred has just occurred within minutes and we're trying to determine exactly what that is.