justified his descent by saying he was invited down by the controller at McMurdo, from 6,000ft minimum to 1,500ft
Gets back to compliance with SOP's, which he obviously didn't do. Both the CAD and airline, who both knew what was going on, are just as much complicit as the crews who were busting SOP's. The controller invited him down? Since when do you think that excuse would stand up to a fastidious management pilot or regulator as reason to bust SOP's?
With reference to the gin clear days, you can suffer whiteout in those conditions as well.
You could go down to 500 feet in DC10, quite safely
You can go down to zero feet in any aircraft quite safely, and with passengers on board, they manage it most times, not always, when landing. The fire fighters can have their problems with terrain clearance as well.
.Report,
https://www.safecom.gov/searchone_new.asp?ID=23587
Not unlike whiteout in some respects.
that video looks to me like a nasty example of ‘hidden ridge’, a known illusion where terrain in the foreground has a similar appearance to that in the background and ‘disappears’ until it starts to bloom rapidly at short range