@prospector - If Judge Greene had asked for testimony from the US military, RAAF and RNZAF pilots who went to McMurdo, then he'd have quickly discovered that while it was a relatively unknown thing on the line, it was a very regular occurrence down there.
Air New Zealand and CAA did liase with those operators, and that is why the approved let down area was as stated, and the minimum altitude was at 6,000ft. It may have been a regular occurence down there, but until Vette used it as an explanation as to why an aircraft flying VMC, with terrain obviously visible abeam and astern, could fly a perfectly serviceable aircraft into a mountain that everybody knew was there, it was called whiteout, Vette termed the phrase sector whiteout.