But they went against policy and the basics for descent below MSA/LSALT. How can that not be the fault of the crew?
morno, there is absolutely no argument about that, the question is why they did it. The reason they did is because that was the SOP adopted. McMurdo controllers stated that no flight ever made its descent from the LSALT in accordance with the laid down SOP, they always came up McMurdo Sound at low altitude, at times below 1,500.
The McMurdo controllers mentioned the difficulties they would have had in monitoring the aircraft on its descent due to the radar limitations (1.5° pencil beam and only calibrated to a 20° elevation - max available being 30°) and the fact that the eastern end of the approach sector was located over head the radar site, and therefore invisible, the controllers also had no information about the approach procedure, or the area in which it was to take place, so the controllers couldn't monitor events, as one controller said, the procedure was "absurd".
The VMC descent procedure was introduced on the penultimate flight where radar monitoring was not required. The controllers had not received the flight plan of the fatal flight and said that they would have disagreed with overflight of Erebus, probably because they had knowledge of ten metre diameter boulders being thrown up to the height of the 16,000 LSALT, and other smaller debris higher. The entire reason the RNC route runs where it does.
It was an operation run by folk who were completely out of their depth, an accident was inevitable, unfortunately as is often the case, good people paid with their lives, "Tombstone Mentality" requires an accident before lessons are learnt.