those pieces the data from the voice recorder and particularly the data recorder. that is going to tell us what happened. no doubt. >> david gallo, how complex, given that the water is relatively shallow, the depths of the area of malaysia flight 370 has been looked for, how complex is the underwater part of this operation? >> well it could be depending on the currents which i'm told are fairly mild but i'm not, i'm told they are. and the visibility especially with divers in the water, that could be complicated too. with shallow water, a lot more sediment from the surrounding land masses and the currents are higher. visibility might be less. not a cake walk but a bit easier than the deep water stuff. >> david, i mean, setting up underwater chambers. what does that entail? >> it's about maintaining the environment which the aircraft is in. especially with the voice