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Transcript: Interview with sonar specialist in the search for MH370

We are out here on Fugro Discovery running calibration and acceptance tests on the sonar systems for the MH370 search. We have two main sonar systems that we're trying to use to locate the aeroplane. We have an Edgetech side scan sonar system which has two transducers tilted down at an angle on either side of the vehicle and that sends sonar signals out and looks out to either side of the vehicle at a certain distance. We also have the Kongsberg multibeam system which is filling the gap the side scan creates directly below the vehicle.

We're looking for targets that we have dropped on the flat, featureless seabed that are about two metres in diameter. We chose a flat, featureless seabed because we are trying to find incredibly small targets and we want to know that we can actually detect those targets and not some other false detection from another object on the bottom.

So what we've done is we've run a series of tests at varying distances from these targets to try to determine how far from the targets we can actually be and still detect them, which means that we can maximise the area that we cover in a survey line, and that will speed up the survey as much as possible in hopes that we will locate the plane as quick as possible.

So with a side scan sonar, what you're going to see is you're actually going to see the water column, which will be no data and then you'll see the actual bottom of the seabed show up, that's called the first bottom return and then from there it goes out and you can see about 1,000 metres to either side of the vehicle and you can still detect the targets. Because of the nature of side scan sonar there is a gap below the towfish that we need to cover and that's what we're using the multibeam system for. So what you'll see in the multibeam is you'll see an actual target that would be directly below the towfish. So what we are trying to do is cover as much area as we can as quick as possible so that we can locate the plane quickly.