The two lessons referred to in your third paragraph had already been learned well before 1979. Inertial navigation systems had been around for nearly 10 years. This was not the first occasion where a programming error had occurred, hence the well-established rule that the AINS was not to be used for landings or other descents below the Minimum Sate Altitude. That is confirmed by Vette in his book and confirmed by Collins when he declared he was VMC. But he wasn't - and he knew it. Sector whiteout didn't have to be covered at the briefing for him to know about it. The fact that Amundson got to the South Pole first wasn't covered at the briefing either, but I'm sure Captain Collins was aware of that fact. He clearly knew about sector whiteout: (1) He said so on the CVR tape; (2) He spent 5 years with the RNZAF at Wigram on the Canterbury Plains, right next to the Southern Alps; (3) He and F/O Lucas visited Operation Deep Freeze shortly before their flight; (4) The phenomena was common knowledge amongst pilots, even those who did not fly in snow-covered regions. He was, therefore, not VMC below the cloud layer, however many times he might have said he was. So everything ended up resting on the AINS, which turned out, on this occasion and on other occasions, to be wrong - but on this occasion the aircraft was below MSA. The error in the AINS was obviously not the captain's fault, but the altitude clearly was. He flouted a well-established rule and the co-pilot did nothing to stop it. When the captain started into that figure-of-eight descent, why didn't the co-pilot say something like: "Ah, we haven't got the radar fix yet"? You can't blame F/O Lucas, who was seated down the back, who heard the announcement about the radar, and who would have assumed, when the descent started, that the position had been confirmed by radar.