the discovery of the debris raises many questions and we look at some of them now with van gurley, a retired naval oceanographer whose company, metron, helped investigators eventually find air france flight 447 after it crashed in the ocean off the coast of south america. and, miles o'brien, our science correspondent and a pilot himself who closely watches the world of aviation. gentlemen, welcome to you both. miles, i'm going to start with you. how definitive, then, is it that this plane piece comes from that boeing 777? >> judy, i'd put it in the high 90 percentile. this is absolutely, definitely a piece of a triple-7. threes only one triple-7 missing in the world, much less the indian ocean, and there the piece is. so what remains to be done is dot the i's, cross the t's, get the serial numbers. every part of a plane has a serial number and a long pedigree attached to it. it's a lot of paperwork and is going to take a little bit of time to say absolutely definitively. >> woodruff: i know you have been watching the story since the news broke last night. looking at what we know so f