different than crashing on land? >> depending on your impact velocity, depending on the impact angle, the effects could be the same on water and land. >> aviation investigator anthony brickhouse takes me through a field of aircraft wreckage used at the university. the lesson learned here, the difficulty of finding a sonar signal of flight 370's wreckage depends on what was happening in the final seconds of flight. at less than 45 degrees we're more likely to see large pieces of aircraft? >> yes, at something less than 45 degrees or around 45 degrees with the typical velocity that an aircraft would be let's say landing at there would be a chance the plane could be relatively intact after it hit the water. >> under this scenario, the 777 could be moving as slowly as 70 miles an hour on impact. at a shallow angle it could be