Prospector , ampan & pakeha boy
I think you all need to appreciate that there is a difference between
cause and
blame .
Taildragger67 made the point perfectly clear back in # 224 with reference to the AA191 crash. You can say that crew in that instance
caused the crash by reducing speed. You can’t
blame them for the crash, as they did precisely what they had been trained to do.
There are striking similarities to this Erebus disaster.
You can say the crew
caused the accident. They flew a perfectly serviceable aircraft into the side of a mountain. Nobody disputes that fact.
However you can’t
blame them for hitting something they could not see. Every step along the way the crew performed in an impeccably professional and competent manner.
( OK . Minor exaggeration. If it was a check flight and I wanted to be nitpicky – “you were a bit late setting the QNH on descent – discussed. Overall session VG apart from the very last bit where you hit the mountain.” 
)- It was entirely reasonable for them to descend as they did
- It complied with their briefing
- They had ATC approval, although as Brian Abraham points out (#268) not legally required, but good airmanship and part of their briefed requirement.
- They did not require a position fix before descending VMC
- (As Brian Abraham points out in (#279 ) the very nature of a VMC descent is that it does not require prior position fixing.) It seems you have already concluded that unless you can invalidate that fact – your argument is screwed.
ampan:
They should have IDed Beaufort Island,
Circular reasoning.
If they recognized they were over Beaufort Island they would have realized they were on a track to Mt Erebus, but they could only have recognize Beaufort Island if they knew they were on a track to Mt Erebus.
Mahon explains this better than I can
One of the criticisms levelled at the aircrew of Flight TE901 had been their failure to identify Beaufort Island. During the orbiting sequences it had been plainly visible and it showed up very clearly in the passengers' photographs. It was certainly many miles to the west of the flight track plotted on the map, when it should have been many miles to the east. The island was clearly marked on Captain Collins' atlas and also, no doubt, on the map which he had procured on his own initiative for the purposes of the flight.
Before I went to Antarctica I must admit that I could see no answer to the allegation that the aircrew should have seen that they were on the wrong side of Beaufort Island. Of all the criticisms advanced so assiduously by the management against the aircrew, this alone had seemed valid. But, as so often happens, there is nothing like visiting the scene and making your own observations.
It was when I first saw Beaufort Island from the air on our approach to Lewis Bay that I realised why it had not occurred to the aircrew of the DC10 that they were looking at Beaufort Island. There it was, about twelve miles to our right. But then I looked further away to the right, towards the mountains of Victoria Land, and I knew that the flight track on Collins' map showed a flight path which would be nearly thirty miles to the right of the flight path of our Hercules. I visualised Collins flying in what he thought was the centre of McMurdo Sound, and looking at an island which he would have seen was unmarked on his map. From his point of view the island he was looking at was therefore nearly thirty miles to the west of Beaufort Island. The display on the HSI panel verified that his aircraft was flying exactly on course, therefore Beaufort Island was far away to his left. It could not be anywhere else. What Collins and Cassin were looking at, in their minds, was an anonymous island lying some distance off the coast of Victoria Land.
I could see now why there had been no fault on the part of the aircrew in failing to detect the identity of Beaufort Island.
On the atlas and on the maps, Beaufort Island is marked as a distinctive black dot on a green background. But there are no green areas in Antarctica. What we actually saw from the Hercules, as I have said, was a rock outcrop protruding through the ice, the outcrop being almost totally covered by snow. It was quite a different visual situation, as I could see, from an aircraft flying over blue sea with every island, covered with bush or trees, easily discernible at long range. Those who had criticised the failure of the aircrew to identify Beaufort Island seemed to me to be people who did not understand the vast white immensity of the terrain. But, in particular, they clearly had not mentally placed themselves in the centre of McMurdo Sound and then asked themselves what they would think if they saw this snowy outcrop over to their right and knew, by reference to their map, that Beaufort Island was miles away to their left, and was probably another snowy mound in the bleak white landscape. Neither pilot had mentioned the island, either before, during or after the orbiting sequences, and when I surveyed this white landscape myself l could see why.
So much for the Beaufort Island theory and the simple unimaginative attribution of fault to the aircrew for not identifying that feature
He goes on to analyse the movements of Peter Mulgrew, the commentator who had been there several times previously and could have been expected to identify Beaufort island. Unfortunately, he was never in a position to see Beaufort Island and break a link in the chain of events leading to the tragedy.
One point seems to be arising in this discussion. Mess with Peter Mahon’s intellect and his analysis of events and you will come off second best.
Prospector
Do you actually bother to read any replies to your postings?
You say
As for the VMC descent, nowhere in the company or CAA requirements for descent is VMC descent an option, it is clearly understood that any descent was to be inside the parameters as laid down and printed many times on this thread, not one of these requirements were met.
Go back to # 267
a)On 8 November 1979, Captain RT Johnson issued a revised descent restrictions memo removing the requirement for ASR to be available and used for descent below FL160 (item 3 of the original memo exhibit 1/8).
There was now no company requirement for radar monitoring if the descent was VMC.
And also where you say
Requirement 4. was
Descent to be coordinated with local radar as they may have other traffic in the area.
Having a bit of a tunnel vision problem here are we?
Just go up 5 lines in that memo and you will find “Delete all reference in briefing 23/10/79. Note that the only let-down procedure available is
VMC below FL 160 …. etc.
However the whole descent memo became
totally irrelevant when the company briefing specifically authorized the crew
to descend to any altitude approved by the United States Navy Air Traffic Controller.
When you say
My interpretation of this requirement would be first of all the flight would have had to have been identified on radar, and position clearly established, before McMurdo radar could maintain separation between them and any other traffic.
Jeez, first you say they have the sole responsibility for terrain and traffic separation (#245), now you require them to be radar identified so ATC can separate them from traffic. Make up your mind!
Note for future reference:
1.They did not require radar identification
2.They did not require a position fix before making a VMC descent You keep flogging the proposition that they made an unauthorized descent. Full marks for persistence, but that argument is patently wrong, and you get shot down every time. They did not make an unauthorized descent. Period.
You have been asked before to brush up on how to reach a valid conclusion via a logical argument
Please do so. Read SR71’s posts for some good examples.
Yes, I know ad hominem attacks are not good debating tactics, and I’ll lose points, but bugger it.
(edited once again for crap spelling and grammar which I only notice after posting)