However, as it was a requirement to be under radar monitoring and in the laid down area that was well clear of Mt Erebus
Not correct, it was not required to be radar monitored, it was to be co-ordinated with radar control as they may have had other traffic in the area. Monitored and co-ordinated are two vastly different things.
In any event, the controller said
We were not aware at the time of the sector within which the Air New Zealand DC1O flights were said to be required to fly. This required sector as now identified to me by representatives of the Royal Commission would in my opinion have been absurd. Any radar controls contemplated by those planning such flights for purposes of assisting in descent manoeuvres would have been virtually impossible since Ice Tower radar does not function above 30 degrees and since without vertical aiming radar or an Azimuth Beam on the TACAN, there could be no adequate ground based control should it have been required. I re-emphasize that to the best of my knowledge, Operation DEEP FREEZE was unaware of any officially approved Civil Aviation Division (CAD) or Air New Zealand flight plan or descent approach. However, had such a flight plan or descent approach been provided for DEEP FREEZE consideration and had DEEP FREEZE agreed to provide radar let—down· assistance, I would have regarded such a plan as extremely ill-advised for the reasons stated.