No problem Walter
Assumption that WX radar could have be used identify the proximity of geography, and by implication then serve as some means of terrain identification and avoidance, was just one of a number misconceptions by many .... "at the time".
Although the system (and remember it's the 1970's version of this equipment being referred to in this particular case and not later/current versions of it) features a Mapping Mode that could (in many cases) paint "a vague" impression of terrain .... it apparently couldn't be relied upon to do so with absolute precision (one would have to know what was actually there in order to interpret returns for what they were) and which is why its manufacturer/BENDEX recommended it "SHOULD NOT" be used for either terrain identification or avoidance.
In fact many misconceptions/falacies became apparent during the course of RCOI.
Some of these were "clear misunderstandings" .... whilst others might have been planted in order to try'n distract certain lines of inquiry.
Another misconception is that which suggested USN/USAF ATC radar at McMurdo should have been able to see the DC-10 on radar .... and by implication McMurdo ATC then able to advise the aircraft of its close proximity to the high ground of Ross Island. The difficulty with this falacy though is radar's effectively "line of sight" (as is radio communication too) .... and there'd likely have been a large radar blind spot below the summit of, and extending behind, the mountain (radar shadow effect) for some distance north of Ross Island. During its orbiting descent, down to 1,500 FT, the aircraft would likely have flown into, and out of, this blind spot "a number of times" .... and in doing so would likely have intermittently appeared, and disappeared from, ATC radar.
The other factor here is "this portion" of the flight was also being conducted in accordance with "VMC protocols".
For the same reasons as above .... radio transmissions would also likely have been intermittently interrupted whilst the aircraft entered, and exited, this same area of radar shadow below the summit of, and behind, the mountain too.
In fact everything seems to have been fine in regard to both radar co-ordination and radio communications throughout the orbiting descent .... until the aircraft neared the 1,500 FT altitude it'd been invited down to. Then .... and as is evident from the CVR transcript (in so far as what's recorded was actually decipherable .... since some of what was recorded was indecipherable and is still hotly contested even today .... and the CVR tape has apparently disappeared since the RCOI) .... radio communications seem to have been intermittently interrupted too (this was originally dismissed as being the result of solar flare activity) .... once again at around those stages of the descent where the aircraft was likely below the summit of, and behind, the mountain.
Shortly before the aircraft collided with the mountain the CVR does reveal one of the crew querying .... "Where's Erebus In relation to us" ? .... to which the captain responds .... "Left about 20/25 miles" .... which is a very clear indicator that they'd no reason to believe their AINS was navigating them anywhere other than down the center of McMurdo Sound and towards their end navigation way point (which unbeknown to anyone at the time was the only one that was "in error") .... precisely as they'd been previously briefed and expected would be the case.
In reality though .... they're actually, and unwittingly, being flown by their AINS into Lewis Bay (due to this same "unknown" navigational way point error) .... directly in front of the mountain .... and which couldn't be seen (nor did they have any reason to suspect it was there anyway) due to the manner in which inherent polar visual illusions came into effect at the time.
The existence of such polar visual illusions has long since been proven both practically and scientifically (although it's always been appreciated within polar aviation communities) and now forms part of civil aviation training around the world as a direct result of this particular accident.
At the time McMurdo ATC were reporting a 40 mile visibility and with no snow showers .... at their locality.
Shortly before the aircrafts collision with the mountain the crew noted they were some 26 miles north of McMurdo .... but at this point .... it's also evident they still couldn't sight anything of the McMurdo area and that they'd been expecting "to have been able to visually identify" given both their remaining distance to run, believed location, and the reported meteorological conditions at the time. This was likely because they were unwittingly staring straight into a blank/snow-covered mountainside that was masked by the since proven visual polar illusion/s (sector white out) without their being even remotely aware of the fact.
The bulk of this moutain also geographically separated them from McMurdo too.
The CVR does reveal the captain at this point stating .... "Actually those conditions don't look very good at all do they" .... to which the F/O responded in agreement .... "No they don't".
Then moments later the captain add's .... "We're almost 26 miles north - We'll have to climb out of this".
In short, and flying VMC, the crew appear to have become apprehensive based on what they "could" see ahead of them versus what they "expected to be able to see", but, "couldn't then see" by that time of their approach given their believed location/close proximity to McMurdo and the reported meteorological conditions.
A discussion then took place between the captain and F/O as to whether or not they should climb away to the left, or right, and it's at this very moment the GWPS is automatically activated .... prompting the captain to calmly/immediately call for "GO'ROUND POWER" .... only it's all over for everyone less than 6 seconds later.
Nobody ever saw the mountain .... either visually or aided by the WX radar.
And nobody appears to have seen the aircraft on ATC radar either .... and even if they had seen it then they likely wouldn't have interfered with the flight anyway given their knowledge that it was both a sight-seeing flight and being flown in accordance with VMC protocols.
The mystery to many among less knowledgeable at the time was .... How could all this be ?
At the best of times "most of the population" at large don't now much about aviation or the manner in which large modern aircraft are flown and navigated. Some hypothesis advanced following, if not prompted by, the CI's report (he was accustomed to investigating light aircraft accidents and not those involving large civil aircraft), but somewhat to the satisfaction of certain other parties at the time (remember the airline was an SOE and the then PM it's major shareholder too), then fuelled some irresponsible media commentary which erroneously influenced, if not confused, many. In fact some of this commentary became "SO REDICULOUS" that it conveyed impressions that ANZ crews might be little more than private pilots flying CESSNA type aircraft rather than highly professional airmen flying highly advance, sophisticated, and modern jetliners of the period.
Uneasiness with this situation (on many fronts) and public demand eventually "forced" the government to convene the RCOI .... for which The Hon.Justice Peter MAHON was appointed (by the then government) to precide over as the RC .... sitting alone at the bench. As I mentioned within may last posting .... MAHON saw through most of the falsehood and deception that was submitted within evidence before him during the course of these hearings and he declared this fact within his report albeit without naming names. The government of the day was "SHOCKED" .... and unsuccessfully attempted to have some of the judges conclusions dismissed (by the Privy Council) due to these not being consistent with both CI's report or the verdict it/the government favoured/expected.
In short .... the government had appointed MAHON as its RC, and in doing so, it'd more-or-less expected he'd simply "rubber stamp" the CI's report .... a fact which even MAHON himself assumed would become the likely scenario when he afterward stated .... "I expected the evidence to support what the CI had to say" .... only he/MAHON, during the course of the RCOI, began to uncover "a whole other side" to the Erebus disaster and one which, as a judge of the High Court of NZ, and by the terms of his engagement as the RC, he simply couldn't close his eyes too.
The occurrence of Erebus Disaster shocked NZ .... but .... what it exposed both corporatively and politically too .... shocked NZ even more.
MAHON was a judge of "real honour" among "Their Honours" (why else was he appointed as the RC) and within the highest court "of NZ" .... and his findings during the Erebus inquiry will forever define/remember him for this.
Following release of the RC's report the PM of the day then exploited the NZ media to attack MAHON in regard to a number of details concerning evidentiary conclusions within his report. MAHON then felt he'd no option other than to resign from the bench in order to able to address/confront the PM's allegations also via the media (typically a High Court judge can't ever engage in public debate in regard to any of his own findings) in attempt defend his own reputation .... and which he successfully did albeit to the shock of the (then) PM and at his own professional if not personal cost too.
At its worst .... the Erebus Disaster demonstrated how NZ can play the often deceptive air accident blame game as well as anyone else has in the world and in the past .... albeit to the countries perceived "loss of innocence".
At best .... justice could at least be seen to have "almost" been done in the sense that the RC's report actually exonerated the aircrew .... but .... this virdict is then diminished by the fact the CI's/governments own report still supersedes that of the RCOI/the MAHON report and which given the recent "public apology" by the NZ government is something that really needs to change/"be changed" .... in order to finally/once'n'for all bring about a "formally recognised" exoneration of the aircrew.
"YES" .... I do harbour fairly strong sentiment/s in regard to the Erebus disaster simply because, for me, it was a case of .... "There but for the grace of God go I"
.... as one, or 2, here are already aware.
I might just "leave it here" now .... just see how we go
MRC
AKL/NZ