The facts have been put forward many times on this and other threads on this subject.
Some facts have, but so has many non facts, such as
But he had received sufficient training for overflight
and
how it is possible to hit that mountain, and be in legal flight conditions is difficult to perceive
Refer to the discussion by
compressor stall as to what constitutes visibility when referring to VFR limits. And an education regarding what whiteout is will greatly benefit.