ARI SHAPIRO, HOST:
Investigators are using a robotic submarine to search the floor of the Mediterranean Sea for the EgyptAir flight that crashed last week. David Gallo is an expert in deep-sea searches. He worked on the hunt for the Titanic among many others and joins us now. Thanks for being with us.
DAVID GALLO: My pleasure, Ari.
SHAPIRO: I mean, you've got this vast murky expanse of water, and you've found a little debris floating at the top of it. How do you begin to figure out where the remains of an airplane are at the bottom of the sea?
GALLO: Yeah, the first thing to do is to know where X marks the spot, where the impact was for the plane on the sea surface. And the objects floating on the surface of the sea - over time they start to drift away from that spot, and the trick is to backtrack. And that becomes the center of a haystack that within which you want to find the needle.
SHAPIRO: And so then what? You drop a plumb-line straight down from what you think the X marks the spot place is and see what's down there?
GALLO: Yeah, that's about it. I mean, you want to make that the center of the haystack and then come up with a plan for how do you begin to work at whatever water depth it is, if a ocean floor is rugged or if it's flat, if it's covered with sediments? Is it hard rock? Are there a lot of currents? So you've got to decide on the technology. You've got to decide on the crew, the team, the talent. And then you got to come up with a game plan.
But the thing about this is in this kind of water depth up to 2 miles plus, you're really talking about mounting a full-scale deep ocean expedition, and that's not a trivial event.
SHAPIRO: What does that entail?
GALLO: Robots, sonars, cameras, navigation, you know, none of the things that we're familiar with up here under the sun like GPS, we don't have that at the bottom of the sea. So we have to bring our own navigation system, our own power.
There's no sunlight at all so you can't see your hand in front of your face. And the search is typically done with a combination of sound, sonar and then camera work to do the detailed things.
SHAPIRO: Given what you described, it sounds like the chances of there actually finding this wreckage is not great.
GALLO: Well, you know, Ari, it's there. OK so that's number one. So it's just a matter of being in the right place, right time with the right tools and talent. It's not easy, it's not routine, but there are teams like the Woods Hole team, and certainly the team that we used to find AirFrance.
SHAPIRO: This is Woods Hole Oceanographic Institute on Cape Cod you mean.
GALLO: Yes, that's right. You know, a team like that - it's not a surprise to them of the kinds of things that the currents, the darkness, the depth, the pressure, the seafloor terrain so that it won't be so surprising. So they're familiar with doing that kind of work.
But, you know, Ari, I have to say it's incredibly frustrating that here we are, a couple of years past Malaysian Air 370, and we're still going through the scramble of trying to find a way to retrieve recorders with information on them that could have been streamed live from the airplane while it was still flying.
SHAPIRO: What kind of a change in technology would you like to see so that this doesn't happen in the future?
GALLO: Well, I think the the most important thing, Ari, is that we learn to track aircraft no matter where they are on the planet, especially over water. And to do that, they need to be able to stream their location - latitude, longitude - with GPS back to a land base.
I mean, the idea that we have to mount a full-scale ocean expedition to find out what happened to that aircraft - it's really the wrong side of the equation to be on. It's a very difficult thing. So streaming capability would be, to me, a real big step forward.
SHAPIRO: That's David Gallo of the Lamont-Doherty Earth Observatory at Columbia University. Thank you for joining us.
GALLO: Happy to help. Transcript provided by NPR, Copyright NPR.