I'd like to develop a thought I expressed in my recent post #721.
Pilotage is largely a matter of feature recognition. Conventional IFR nav is very different. These scenic flights were a highly unusual mix of conventional IFR nav and highly unusual low level mountain flying in a wide-bodied air transport aircraft. They subscended the transition from conventional instrument-borne nav to purely visual pilotage under IFR to an extraordinary degree.
Marine (maritime, not the grunting variety) pilots, from whom we take our name in aviation, are pilots who have a highly detailed knowledge of both the waters and the land-forms within their area of expertise. They have a highly developed and well tested ability to recognise position from even momentary and fragmented glimpses of a landform in crappy vis. That's why they earn the big bucks (and the bagfulls of free booze & baccie).
What was required of the pilots of these scenic flights, once they descended below the formal MSA, was the navigational skill which we call pilotage. Pilotage in such a locale as McMurdo requires local knowledge, a knowledge of which the five flight crew members were entirely bereft.
On their briefing day, a little under three weeks before the crash, the two crews were given a sim session, specific to their planned flight(s). The purpose of the sim session was to refresh their awareness of the technicalities of Polar Grid Nav, with specific reference to the very substantial differences between Grid bearings/headings and those of True or Magnetic North and a detailed refresher on the operation and interpretation of the INS in that regime.
In those days the visuals on even the most sophisticated sims, such the the one for the Diesel10 in the 1970s, did not model hypsographic data and could not possibly be used for showing the 3D visual appearances of remote islands in any weather.
There were/are two islands proximal to the programmed track towards Ross Island. One to the left, then one to the right.
Mulgrew would have recognised the landform of either or both of those islands. He'd seen both before, just like a marine pilot of his own competence.
I muse that if he had been present on the flight deck, doing his commentary thing on the PA, when Scott Island passed by the left wing, and then when Beaufort island passed by on the other side, which he was not, his commentary might have jangled with the SA model in the minds of the two pilots. In that scenario, which sadly was not the case, then perhaps Captain Collins might have saved the day.
Just a thought. Albeit one which may be coloured by more modern concepts of CRM than were widespread outside United Airlines in the 1970s.