Lots of theories as to why this would happen and what could have prevented it BUT ... we used to show a video during recurrent CFIT training of a 47 Classic (two pilots AND A FLIGHT ENGINEER) who misheard, and accepted, a clearance on a Non Precision approach to 400feet (instead of "cleared 2400 feet") and sat, fat, dumb and happy through EIGHT GPWS "Pull up" calls with no reaction and the last recorded remark before impact was ... "Oh ****". Combined crew flying hours totalled many thousands.
So ... any more helpful ideas as to how to prevent people doing what people have always done and will continue to do?
There is one which hasn't yet been mentioned and which will NEVER happen - institute an Aircraft Commander - an experienced type-qualified pilot on the jump seat who has no part in the physical flying of the aircraft but who is in overall command. NOTHING concentrates the mind in Flight Safety terms, as regards self-preservation, more than being responsible but NOT having control.
