Surely the search team are now looking for further debris in a 100 mile radius of the island? If there was indeed a controlled impact into the water, it is very likely that there would have been many buoyant items afloat (both a/c parts and from potential evacuation). There has got to be a strong chance that some these items have made their way to a similar area???
If nothing further is found, lets be honest, there is still a very slim chance of finding the remainder of the fuselage - 18 months is such a long time!
Lets hope something productive comes from this crucial find!
God bless