And then the mandatory requirements are spelled out, as has been stated many times in this thread, not one of which was complied with. If even one had been complied with the disaster would have been avoided.
Prospector, you are quite correct in saying that none of the requirements were met. As pointed out by
grummanavenger, one flight diverted, but all the other flights didn't comply with requirements either, which were (Bolding mine),
1.17.28 On 10 August 1977 Air New Zealand letter HO:B:22 requested authority to conduct five flights overflying Antarctica in the McMurdo area undertaking to operate these flights to the specification earlier submitted with the following exceptions:
“a. A proposal to permit descent to 6000 feet QNH in VMC or by the approved NDB procedure in IMC provided that:
1. Cloud base to be 7000 feet or better.
2. Visibility reported to be 20 kms or better.
3. ASR is available and used to monitor flight below flight level 160.
4. No snow showers in the area.
Flight in the McMurdo area below flight level 160 will be restricted to an arc corresponding to a bearing of 120° Grid through 360° G to 270G from the NDB within 20 nm in order to keep well clear of the Mr Erebus region.
many of us here believe Collins performed poorly - in a way that cannot be explained away by precedents, commercial pressure, optical illusions, or to use megan's catch phrase - "normalisation of deviance"
PapaHotel6, as with all of us you are entitled to believe what you wish, my "normalisation of deviance" comes principally from the failure of all but one of the previous flights to comply with the requirements I state above, and the airline knowing what was going on not doing anything about it.