Hi there
from what we have gathered in the last few episodes it seems that Widmore is blaming Ben for the fake crash and that Ben is blaming Widmore for the cover up/fake crash - WHO is actually telling the truth only time will tell...
But what we do know is that both are prepared to do just about anything to achieve their means and BOTH have motives for faking the crash. In Ben's case it is so that the island is kept hidden from the world and in Widmore's case also so that the island can be kept hidden from the world so that he can find it and exploit it himeslf. Both are looking guilty BUT this episode we saw Tom give proof that Widmore orchestrated the fake crash and quite clearly he has the means to do so.
I still don't trust Ben, those documents Tom had could well be fake themselves in order to manipulate Michael - and was poor Michael manipulated or what.
I still have an open mind as to who actually faked the crash.