there's a lot of information about the fphysics. i can't imagine it would give us any clues about why this happened or how it specifically happened. >> so when we see the pieces being put back together in warehouses like twa flight 800 as remarkable as it looks it yields scant information about what happened before the actual crash. >> it would give the approximate cause. was it fire? there'd be evidence of fire. was it an explosion of some kind? rapid decompression, you might find evidence of that because of fractured lines. it would give you that kind of information as far as what might have happened prior to the accident, but it really wouldn't tell you who or why. >> or why. something that you mentioned to me just before we popped up on the air after this break, the cockpit voice recorders only record two hours. and that's something that the union, the pilots union, negotiated. they didn't want anymore of two hours of recordings for privacy. in this scenario what we know about this flight having possibly flown for seven hours.