The aircraft is flying in direction X, the axis. Most debris is found in a path along direction X. Some debris is found along direction Y, say at X + 60 degrees, as if a missile had struck to create the off-axis debris.
With a quick look I can’t find any backup, but remember seeing this along with a chart back at the time.
OK this is all new to me and very interesting so please forgive the questions. So if an airplane is hit at point X then I assume that would be where the off-axis debris is generated? But the plane broke up at point Y and hit the water at point Z, both of which could be miles away from the point of impact considering the speed the plane is traveling at. So wouldn't that make if difficult if not impossible to locate the off-axis debris?