Erebus 25 years on

[Fantome]

It's a big leap of faith to use this to explain away a CFIT event which took the lives of 257 people.

. .just a little quibble questioning the need to dramatise . To tell us yet again that this was a big one. Implying that a smaller one numerically would be somehow different to explain away. . . . refer if you like to my #824 about the perils or the positives of straight or crooked thinking. . .

[jack red]

good post compressor stall and definitely food for thought.

[ampan]

True. So much for Mahon and Vette's "false horizon" nonsense.

[compressor stall]

Another side tale

There's another old whiteout story from the days of yore. I can't remember who told me, but it was back in the days of the dogs, before my time.

Some guys and their dogs had sledded out to one of the remote huts and harnessed their dogs. Out one particular window was a view of the endless white snow sheet. The next cloudy morning they were perplexed by the appearance of a mountain in the distance, where there was none. This alone is not unusual, I have seen mountains from far over the horizon that are refracted in the lower atmosphere to become visible, and another rare phenomenon sometimes even has them reflected upside down, but I digress.

Curious at the appearance of this mountain, the intrepid folk ventured outside and nothing was visible in the distance.

Back inside they ventured and they could see it.

Back outside they went, and walked behind the hut. Low and behold a husky had done its business about a metre from the window on a small sastrugi (small snow ridge).

The whiteout effect is so powerful, and the brain so easily deceived even to those who spend time in it, that they mistook a dog turd at waist height one metre away for a mountain range 100 miles away.

[megan]

PapaHotel6

Vette's theory is highly speculative. It's a big leap of faith to use this to explain away a CFIT

Of course any theory is an assumption not verifiable by fact, since there are no observers, or evidence such as film. All you can deduce is probability. If some one were to claim suicide, would that stand as a reasonably probable explanation? Has happened previously (767, 737), in my book a ridiculous proposition of course, but how does one go about proving in absolute terms that it wasn't?

Suggest you have a reread of the opinions of Captain Briska USN Chief Opthalmologist & Flight Surgeon, Captain Grinsburg expert on illusory phenomena Ph.D Cambridge, Mr. Green Psychologist specialist in flight skills and visual illusion who is a consultant to the RAF, Mr. Shannon Vice President Operations Bradley Air Services who was experienced in Antartica operations.

Can you come up with an alternative suggestion/s to the theories propounded by the above gentlemen?

[jack red]

True. So much for Mahon and Vette's "false horizon" nonsense.

that's what I thought to until I read compressor stall's next post about another side tale.

[PapaHotel6]

Megan said:

Of course any theory is an assumption not verifiable by fact, since there are no observers, or evidence such as film. All you can deduce is probability.

Correct, but you don't seem to extend that same latitude towards people who disagree with you.

With respect to the "false horizon" theory - it's just one (unqualified) man's idea. Look at Vettes' video. He calls his work "scientific", but there is nothing about his ramblings that are 'scientific" at all - insofar as science requires establishment of validity. He can't even say the word "Antarctica" properly.

Some people have no problem believing this wild theory, yet the suggestion that the crew might not have been VFR for example, while descending from high altitude with cloud all around them and blanketing the area which the flight was to go, is dismissed as wild speculation. It's a curious double standard.

Can you come up with an alternative suggestion/s to the theories propounded by the above gentlemen?

Yes. Not VFR at 2000', the crew descended further to 1500' (why else would they have). At 1500' they found themselves flying in a ping pong ball. There was no clear surface/horizon definition. It was hard to tell the difference between cloud and ice, as Collins himself had predicted. And they flew the aircraft into the ground.

[megan]

Correct, but you don't seem to extend that same latitude towards people who disagree with you.

They are not disagreeing with me, they are disagreeing with the evidence as presented by Chippindale or Mahon, which is all I quote.

With respect to the "false horizon" theory - it's just one (unqualified) man's idea.

I'll accept that, but what have you got to rebut what the experts I mention in the previous post had to say?

At 1500' they found themselves flying in a ping pong ball. There was no clear surface/horizon definition

You are quite right, there was no clear surface/horizon definition AHEAD. Twelve seconds prior to impact (.86 miles by my calc) the co-pilot said it was clear to the right. Why would he be saying "clear"?

[Whiskery]

I direct this scenario to compressor stall and maybe megan, as you two appear to be the only ones in recent posts to have a qualified handle on the subject of whiteout. Apologies to others who have spoken about it.

Would it be reasonable to assume if they were flying over McMurdo Sound they would not have encountered this visibility problem of whiteout? So if they thought they were where they should have been, what were they expecting to see and what did they actually see? Visibility seemed OK from the CVR, forecast weather and passenger photos so maybe it was the route change that fooled them. They were not where they expected to be and because of whiteout, they did not see what they expected to see. Is that fair or not?

You might say one may really have to consult with the crew to find out what happened. I know that is not possible so I'm not surprised this accident is so fiercely argued about.

[PapaHotel6]

Can I just clarify - we are not debating the presence of whiteout in this incident. That the crew encountered uniform white lighting with loss of surface definition, while not a "fact", seems overwhelmingly likely and doesn't seem to be seriously contested by anyone. What we are debating is whether or not these conditions would necessarily have tricked them into believing they were in good VMC at 1500'. Correct?

[Chronic Snoozer]

I have a foot in both camps. I largely agree with the faults identified by Mahon concerning organisational factors, however with qualification. Chippendale was succinct. I don't think I can fault their two coexistent causes of the accident being those detailed in paras 393 and 3.37 of their respective reports. Mahon overreached in other areas, Chippendale didn't quite go far enough, IMHO.

But given that the forecaster said at McMurdo

1.7.4 'We have low overcast in the area at about 2000 feet and right now we have some light snow but our visibility is still about 40 miles.

Why would the captain decide to descend and establish below that weather given what he knows about whiteout and that he would be navigating visually without any ground aids, knowing that under his flight rules he could not operate below MSA purely by reference to the INS?

Mahon's report also contains this assertion; para 28

'To the left, clearly visible under low cloud, was the thin strip of black rock indicating the shoreline of Cape Tennyson about 13 miles away. To the right, also clearly visible under cloud, was the strip of black rock and the lower slopes of Cape Bird, indicating its shoreline about 10 miles away. It therefore followed that as the aircraft had approached Mt. Erebus it was flying in skies in which there was perfectly clear visibility for at least 23 miles'.

It appears he simply added the distance L & R to reach the conclusion that there was 23 miles of visibility. Notwithstanding that, although the visibility is claimed left and right it refers to ground features and vertical visibility is often better than the horizontal visibility so I'm not sure the inferred visibility was as good as stated and if it was then this calculation is questionable.

I've no doubt the whiteout phenomenon prevented anyone on the flight deck seeing the mountain which they did not expect to see. But I also tend to agree with Mahon that they were not uncertain of their position. They were exactly where they 'thought' they were, hence no alarm.

I've learnt a great deal reading this thread. Thank you for the ongoing discussion, it has opened my eyes on a great number of issues.

[megan]

given what he knows about whiteout

We have no idea what he may have known about whiteout. The crews weren't briefed on it, as pointed out by Chippindale. ampan deems the fact that he flew around Wigram and made a trip to McMurdo made him full bottle. As compressor stall points out, theory doesn't cut it, you have to see it to fully understand.

Even making prospectors beloved airline descent wouldn't remove the possibility of a crew experiencing full blown whiteout, as Chippindale points out.

Once again, must comment on the airline ethos vis–à–vis "Normalisation of Deviance". Americans reported observing flights operating in and out of cloud while reporting they were VMC. As I have said previously, the airline on these flights was an accident looking for a place to happen.

[ampan]

megan #1068: Why did First Officer Cassin say it was clear to the right? Because he thought it was. He was wrong, It wasn't clear to the right - refer Mt Bird.


megan #1072: Captain Collins and F/O Lucas went to the Christchurch end of Operation Deep Freeze, not the McMurdo end.


If "you have to see it to fully understand", what difference would it have made to have covered the issue in the briefing? The point is that despite it not being covered in the briefing, the captain knew of the problem. hence the locking of the aircraft back onto the nav track. Did any of the other VMC pilots do that? Not one. They were comfortable relying on their eyes. Captain Collins was not, because it was "very difficult to tell the difference between the cloud and the ice."

[PapaHotel6]

In the end it doesn't matter what Collins did or didn't know about what we are referring to as "whiteout". You don't even need to be a pilot to know that cloud can completely hide snow covered terrain; and Collins knew this too - as he demonstrated in his statement above. Yet he put himself in the precise situation he was cautioning himself about only minutes before.

[Whiskery]

the airline on these flights was an accident looking for a place to happen.

That is a good point megan. Someone pointed out earlier, all the other flights came back safely in spite of allegations of low flying and cloud in the area. The only difference this time was a very late track change which was not relayed to the crew. The whole thing is very sad really.

[prospector]

The only difference this time was a very late track change which was not relayed to the crew. .

I would disagree with that, the only difference was that the weather was well below that required for sight seeing around McMurdo and Scott bases.

There was an alternative, passengers had been advised that this was always a possibility if weather precluded the McMurdo Scott Base tour.

[ampan]

Ditto


“The only difference this time was a very late track changewhich was not relayed to the crew.”


The waypoint was not where Captain Collins thought it was, but that had been the situation for two years: Previous crews were told that the waypoint was at McMurdo Station when in fact, it was 27 miles west. So it cannot be said that misinformation about the waypoint (and therefore the nav track) was the difference. All those who came back over the previous two years were also misinformed, albeit in a different way.


The first material difference was that the previous crews who went low on the basis that they were VMC had blue skies and were, in fact, VMC. They could see where they were going. They were not pretending.


The second material difference is that the previous crews did not use the AINS to go below MSA, firstly because it was not allowed, and secondly, because they were not pretending to be VMC. They could see where they were going.


The cloud issue never came up with previous crews, because the only time the McMurdo Station area was covered in cloud, the crew diverted to the South Magnetic Pole.

[PapaHotel6]

Ditto for me too.

Whatever we say about "normalization of deviance", Collins on this flight took that deviance to a whole new level. There was no comparable descent in the history of Air NZ's Antarctic flights.

Which brings me onto my next point. *If* we accept that in this case there was institutional pressure on the pilots, creating over time a situation of normalization of deviance, surely all that does is puts said deviance into context, and help us understand why it occurred. It doesn't make said deviance right, or acceptable practice, or remove responsibility.

[megan]

The first material difference was that the previous crews who went low on the basis that they were VMC had blue skies and were, in fact, VMC. They could see where they were going. They were not pretending.

how do you know they had blue skies and were in fact VMC? Evidence is that crews were observed operating in and out of cloud, though telling McMurdo they were VMC. What is your definition of VMC?

Collins on this flight took that deviance to a whole new level. There was no comparable descent in the history of Air NZ's Antarctic flights

An extremely bold statement. We have no idea what previous flights did, other than extremely few complied with SOP. Some certainly didn't comply with VMC rules. The fact that they arrived home is not testament to what did, or what didn't, transpire in the conduct of those flights. We know that some certainly didn't operate VMC, though claiming they were

Previous crews were told that the waypoint was at McMurdo Station when in fact, it was 27 miles west. So it cannot be said that misinformation about the waypoint (and therefore the nav track) was the difference. All those who came back over the previous two years were also misinformed, albeit in a different way.

All that does is heighten the fact that that none of those crews had any idea where the waypoint resided. The question to be asked if the crews were aware of the waypoint location, why did none ask why is it called McMurdo, when in fact it was not. And what about the missing leg from the false McMurdo to the real McMurdo for the company cloudbreak. Collins didn't ask either, even though he had plotted the false McMurdo.

It doesn't make said deviance right, or acceptable practice, or remove responsibility..

Well said PH, the responsibility lay at all levels of the airline, and the regulator. They were all children out for a frolic not knowing what they were doing.

[PapaHotel6]

how do you know they had blue skies and were in fact VMC?

I guess we don't - but they said they were, and there was apparently photographic evidence. Make of that what you will.

Evidence is that crews were observed operating in and out of cloud, though telling McMurdo they were VMC.

Reference please?

We know that some certainly didn't operate VMC, though claiming they were

You don't know this at all (what is it bout the Mahon camp that makes them feel they have carte blanche to decide what is "known"??)

The fact that they arrived home is not testament to what did, or what didn't, transpire in the conduct of those flights.

Tell that to every person on TE901 who wasn't lucky enough to be on one of those flights instead of 28 Nov' 79.

All that does is heighten the fact that that none of those crews had any idea where the waypoint resided.

Which is not a major issue, because at the end of the day it doesn't really matter where a high altitude waypoint is. As is evidenced by the fact that there was no outcry after Capt. Simpson's flight.