JUDY WOODRUFF: 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?

MILES O'BRIEN: Judy, I would put it in the high 90 percentile. This is absolutely, definitely a piece of a 777. There's only one 777 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 on an airplane has a serial number and a long pedigree attached to it. It's a lot of paperwork, so it will take a little bit of time to say absolutely, definitively.

JUDY WOODRUFF: So, looking at this — I know you have been watching this story since the news broke last night. Looking at what we know so far, what does it tell you?

MILES O'BRIEN: Well, it's interesting. The way it — the damage pattern presents itself is interesting. A lot of people have been saying, well, perhaps it fell off as the aircraft struck the water.

But I have been talking to some experts who have looked at it and said two things that are interesting. The leading edge is not very damaged at all, and the trailing edge, if you look at it, almost looks like it's been torn like a piece of paper. That would indicate stress damage.

In other words, it could have been fluttering, and that would suggest that it tore off in flight. So perhaps this aircraft was diving in a spiral at a very high rate of speed, and pieces of it were falling off.

JUDY WOODRUFF: So, that's still speculation at this point?

MILES O'BRIEN: It is, but the damage pattern supports that.

JUDY WOODRUFF: Van Gurley, based on what you know from looking for plane parts, knowing about ocean currents, what do we know? What does this tell you, I mean, what was known about where this plane possibly went down and the fact that this may be a part all the way over close to Madagascar?

VAN GURLEY, Former Navy Oceanographer: So, Judy, this begins to answer some of the big W-questions that have been plaguing this since the beginning.

First, what happened to this flight? If this, in fact, is traced back to the Malaysian Air 370 aircraft, this says definitively the plane crashed at sea and it provides the ability for those families to get the closure they have been looking for since this began.

The second question it answered is, where would it have crashed? Now, everybody would love, and I would love to be able to say that we will be able to use some scientific method and say, because we found it here, it must have been here. The science doesn't really support that type of accuracy.

But what it does tell us, if we look at the ocean currents in the Indian Ocean, is that, if this is, in fact, from MH370, that the plane most likely went down — that the plane definitely went down in the Indian Ocean and most likely in the eastern to southeastern Indian Ocean.

And so that begins to sort of draw circles and narrow down some of the wilder speculation that's been out there for the last year-and-a-half.

JUDY WOODRUFF: And what about the barnacles they have shown that are on this so-called flaperon, this part of the wing?

VAN GURLEY: Right.

So, that is very strong evidence that this part has been at sea for quite a while, and it's not something that was lost off a transport ship last week and just happened to run up, wash up on this beach. For that type of marine growth to accumulate means that the piece has been floating out at sea for a while.

I think the marine biologists, if they get a chance to look at it, can start looking at how much growth is there and then provide a better estimate of how long it must have been at sea for that to have happened.

JUDY WOODRUFF: Miles, what are the questions you and others who look at aviation and aviation safety have going forward? I mean, how much does this narrow our understanding of what could have happened?

MILES O'BRIEN: Well, you can learn a lot from the pieces, the wreckage. It can tell a real story for us.What exactly happened? Did it break up in flight? Was there a fire? Was there some sort of explosion?

The pieces can actually tell you this kind of information. Ultimately, however, the only answers are at the bottom of the sea. And, hopefully, this will help people at least have the confidence to know they're looking in the right part of the world, that, on that circle that Van was referring to on the map, there is some degree of confidence that they're looking in that precise place in a — within plus or minus a few miles, whereas there was all this concern that perhaps, after that last communication with the satellite, it might have glided on for some several dozens or even close to 100 miles, making the search much less accurate.

So, I think this helps make the search more accurate and ultimately might get us to some answers.

JUDY WOODRUFF: And, Van Gurley, what about in terms of parts of the plane that will float, parts that would sink? What do we know about that?

VAN GURLEY: So, again, depending on how the aircraft is constructed, if there's air voids and pockets, foam inserts, those types of things, then the plane — the parts would tend to stay on the surface for a longer period of time.

So, one of the things that I think I already have read in the reporting that has already started up is, if you find one piece, are there more somewhere in that part of the ocean? Every part moves differently in the ocean currents and the winds. It's a very complex pattern, so it's not to say we will find more things on the same beach, but it's a high indication that the earlier projections that — if things were going to wash up, you kind of wanted to look around Madagascar, around the islands like Reunion and down off the west coast of the southern part of Africa.

So I think a continued search for those regions, looking for more pieces, parts might help to backtrack and make that — refine that, that Miles was talking about, to sort of help narrow the search area, but it is still going to be a very long process.

JUDY WOODRUFF: And so, just quickly, Miles, the next things that have to happen are what, broadening the search in that area?

MILES O'BRIEN: Exactly. Keep plowing through the ocean along that circle that was drawn by that satellite, Inmarsat satellite, that gave them a basic idea, a big swathe of ocean, to be sure, but this helps them have that confidence. And then let's hope we can find some more debris.

JUDY WOODRUFF: Miles O'Brien, Van Gurley, it's early, at least at this phase of the story. We thank you both.

VAN GURLEY: Well, thank you.

MILES O'BRIEN: You're welcome.