Paul Holmes and Erebus

[ampan]

The difference between the actual track and the nav track was, presumably, caused by the drift in the AINS.

If you move the actual track over to the previous nav track (ie, the yellow line), with the same amount of AINS drift, then the aircraft gets very close to Mt Bird, which is 1766 meters or 5790 feet. That's fine when he's at 10000 feet heading back to the north, but when he turns back towards the south and descends to 1500 feet, Mt Bird, which he thinks is to his left, would become important. Yet even after the F/O says it's clear to the right, he decides to go left, at an altitude of 1500 feet towards a 5790 foot mountain.

I think it was a case of "I think I'm here, but I might be there."

[DozyWannabe]

Originally Posted by ampan

What was AirNZ to gain by pinning it on the crew?

Originally Posted by Brian Abraham

Absolution.

Maybe, but just as importantly, if it ever became common public knowledge that the co-ordinates were changed without the crew's knowledge (it was in Chippindale's report, but as more of a footnote than anything else - the press certainly didn't report it as a contributory cause), then it would only be a matter of time before the lid was lifted on their lackadaisical organisational and communications habits - not only something that Morrie Davis could not survive politically, but would also leave Rob Muldoon with egg on his face.

Which, as it turns out, was precisely what happened at the Mahon inquiry and became the reason for the political backbiting and desperation on the part of Muldoon and his old boys' network to try to get it overturned.

This is why I'm inclined to be more favourable to the NZALPA/Mahon version of events - ANZ did everything they could to prevent any deviation from their side of the story from seeing the light of day because the management knew it would be their careers on the line. The NZALPA delegation (and Vette in particular) were willing to risk their careers and decades-long friendships in order for the truth about the accident to come out - the aviation industry is rarely forgiving of whistleblowers, even if they turn out to be right. Indeed - after the Mahon report was published Vette himself was reinstated as an ANZ Captain, but he never regained his seniority. In my opinion it says a lot for the man that he considered it a price worth paying.

Originally Posted by ampan

If you move the actual track over to the previous nav track (ie, the yellow line), with the same amount of AINS drift, then the aircraft gets very close to Mt Bird, which is 1766 meters or 5790 feet. That's fine when he's at 10000 feet heading back to the north, but when he turns back towards the south and descends to 1500 feet, Mt Bird, which he thinks is to his left, would become important. Yet even after the F/O says it's clear to the right, he decides to go left, at an altitude of 1500 feet towards a 5790 foot mountain.

I'm eyeballing with an image editor here, and the resolution is not high enough to tell for certain, but even with an equivalent eastward drift, it looks like they'd have made it if they'd turned left (Mt. Bird is only 5790ft at the peak and they'd have been over the lower western slopes - remember that he was about to command a *climbing* left turn with TOGA power). Not shown on that graphic are the Cape Bernacchi cliffs to the crew's right, which would have also been problematic if the drift had been westward rather than eastward. I'm convinced that Collins' left turn was because he could see the cliffs on his side but not Cassin's, and if what we're told about him as a pilot is correct then he felt he should take the responsibility wherever the chips should fall.

[ampan]

Go around power was only ordered after the GPWS sounded.

PS - Vette wasn't reinstated, because he was never suspended in the first place - and he didn't lose any seniority. He simply quit.

[prospector]

Dozywannabe,

" That we don't know exactly what the radar situation was in the four minutes or so immediately prior to impact

"


Whilst you are studying that illustration of tracks and relative positions, would you please advise how you believe any radar return was possible???

[DozyWannabe]

@ampan - See the interview with Vette in Impact Erebus Part 7 - he did come back to ANZ, but not to the same position he vacated.

@prospector - right where it says "VHF contact" for starters. If the controllers saw it there they should have warned them. Your whole attitude to this case is like one of those teachers who say things like "I suppose if Wilson told you to jump off a cliff and Simpson said it was safe you'd do it yourself? You broke the rules so it's your fault."

Except in this case Wilson was the company-appointed briefing pilot who told them that the rule could be broken and Simpson was the pilot who attended the same briefing and did in fact come home safely. The crew had every right to trust that they would be too if they followed instructions which - as I said - they did *to the letter*.

[prospector]

Doztwannabe,

Come now, does that answer my question??, VHF contact was well before 4 minutres prior to impact.

@prospector - right where it says "VHF contact" for starters. If the controllers saw it there they should have warned them

That return was only for a very short time span, the controller may not have even been looking at the screen, after all that was the only inbound flight and the Captain had requested, and been given a VMC descent. It would not be incumbent on the controller to say anything, let alone question a Captain whether he knew he was VMC or not.

Your whole attitude to this case is like one of those teachers who say things like "I suppose if Wilson told you to jump off a cliff and Simpson said it was safe you'd do it yourself? You broke the rules so it's your fault."

No not really, more like forty years flying and now, still alive, enjoying retirement. And your strong opinions backing Mahon are based on what aviation experience??

There are many reasons why I believe Mahon was wrong, but just an example or two. It has been stated that many pilots used the weather radar installed in the DC10 in mapping mode down at the ice and they all got a good return from Ross Island. This did not fit Mahons theories so he ruled it out.
No where can I find any reference as to whether Flt 901 was even using the weather radar in mapping mode to get a confirmation of their position.

He believed CAA could alter the MSA because these were sight seeing flights, obviously no appreciation of why MSA's are imposed.

[henry crun]

DozyWannabe: You say "right where it says "VHF contact" for starters. If the controllers saw it there they should have warned them."
Just because there was VHF contact does not mean there was radar contact; there are a number of reasons for that.

Can you give me one good reason why the radar controller, IF he had observed a brief paint, would not have advised the pilot of what he had seen ?

On a separate subject, I note you never replied to the questions I asked in post #131.

[ampan]

Capt Simpson: "And then on the day of the flight after inserting all the waypoints for our flight into the navigation computers, I then selected pertinent ones, and related them to the charts namely the Auckland Islands, Ballenys, Hallett, and my McMurdo position, Cape Campbell, just to make sure that the latitudes and longitudes on my flight plan were in fact going to take us to those points." (The Erebus Papers p682)

If Capt Collins had done the same thing for just one of those waypoints, the accident would not have happened.

[DozyWannabe]

Originally Posted by prospector

Come now, does that answer my question??, VHF contact was well before 4 minutres prior to impact.

I've been thinking about that - do we know that the erased 4 minutes were the 4 minutes right before impact? I'd have to look it up.

That return was only for a very short time span, the controller may not have even been looking at the seceen, after all that was the only inbound flight and the Captain had requested, and been given a VMC descent. It would not be incumbent on the controller to say anything, let alone question a Captain whether he knew he was VMC or not.

Maybe, but given that the call for VMC was incumbent upon a radar ID before the controller cleared it the sensible thing to do would be to keep tabs on them for as long as possible. I'm pretty sure there was at least one other flight in the vicinity at some point though because the pilot was interviewed by the news team that went down there IIRC.

Still - it wasn't that busy. What else did the radar guys have to do but keep an eye on things?

No not really, more like forty years flying and now, still alive, enjoying retirement. And your strong opinions backing Mahon are based on what aviation experience??

Consider yourself fortunate then - there are plenty of good pilots no longer with us through either a momentary slip-up or even through no fault of their own, just bad luck. Was your experience purely military/GA/training or did you fly the line at some point?

I'm happy to admit that I'm no professional aviator, my experience being limited to my Air Cadet days and getting the odd go in a light aircraft. However I've been an aviation enthusiast and self-taught safety freak since you could count the years I'd been around on two hands - I blame watching "A Fall From Grace" on the BBC when I was eight.

My opinions, which tend towards Mahon's side of the argument - but do not discount anything out of hand as a rule - come less from the aviation side of things, and more from the systems analysis theory I learned as a Software Engineering undergraduate. From my own learning I cottoned on to the fact that accident analysis lines up very closely with the things I learned, and that what applies in systems failure analysis as regards technology can also apply to human-dependent systems, like the one used in ANZ's nav/ops/flight crew communications. I went into some very long and dull detail about "organisational entropy" a few posts back, and if you didn't read it I'd be very pleased if you would and let me know what you think.

As I've said, Chippindale's technical investigation was for the most part pretty good if you judge by the standards of accident investigation in the '70s. However, if his report became the one defining document of the event then a lot of things we now know because of the Mahon report would in all likelihood have been learned the hard way later, probably with greater loss of life. The reason for this is because it was artificially constrained to the piloting aspect, leaving the organisational problems as a footnote. My personal opinion is that this was because he was prevented from digging too much deeper because the conclusions he set out to prove were exactly what his employer and the national flag carrier wanted. As an undoubtedly competent engineering pilot in his military days, it's only natural that his investigation would take that path, but his lack of experience in line operations meant that some of his conclusions were based on incomplete information.

In short, Chippindale came very close to nailing the "what" and "how", but his interpretation of "why" left something to be desired. Because Mahon had to learn the ropes of aviation accident investigation, but was already quite well-versed in picking apart tangled corporate issues thanks to his legal career, he was able to set events within a much broader context. As I've learned from nearly 10 years on this forum, commercial aviation is rarely the "tight ship" it presents to the world, and was even less so 30-odd years ago. What Mahon and his team uncovered was the result of industry-wide growing pains. The jet age and the advent of widebodies presaged an explosion in air travel, but the regulations binding it and the regulatory bodies tasked with making sure the line was toed were stretched beyond their capacity to deal effectively with it - the airlines themselves were clearly improvising to some extent and were fostering among their crews an idea that things were better taken care of than they actually were.

Chippindale's position (and yours) seems to be that the crews should have known better off their own back and that the military habit of taking ultimate responsibility for everything should have been the norm for commercial operations too, but the fact is that it wasn't, in fact it never could be simply because of the size and complexity of the operations concerned. So in line ops a pilot *has* to trust the other departments implicitly to some extent, or the whole operation would grind to a halt. In this case they performed all the necessary checks - in fact went further in some ways - and stuck to what they had been told at the briefing believing that it would keep them safe. Mahon's opinion (and mine) is that they had every right to be entitled to do so.

Originally Posted by henry crun

Can you give me one good reason why the radar controller, IF he had observed a brief paint, would not have advised the pilot of what he had seen ?

Not a good reason, but he simply might not have been paying close attention to where it was

On a separate subject, I note you never replied to the questions I asked in post #131.

I'll go back and check - if I didn't answer it usually means I didn't have one at the time.

Originally Posted by ampan

If Capt Collins had done the same thing for just one of those waypoints, the accident would not have happened.

What if he did? What if he did just that but (again - reasonably, because he had not been notified of any change) used his notebook rather than the printout? The irony is that because of no concrete evidence either way, by misplacing or destroying the contents of the notebook ANZ made sure that even those sympathetic to their argument must accept the possibility.

[prospector]

Dozywannabe,

I can appreciate where you are coming from, and your interpretations, but
statements like

Maybe, but given that the call for VMC was incumbent upon a radar ID before the controller cleared it

is simply not correct. By requesting VMC descent there was no requirement to be identified, the controller would likely have advised of any other traffic in the area, but the Captain was declaring he was happy to maintain his own terrain and traffic separation

[ampan]

"Very hard to tell the difference between the cloud and the ice"

According to Vette, Capt Collins got his wings in 1954 and left the RNZAF in 1958, while stationed at Wigram, Christchurch. In 1956 the RNZAF organised an Antarctic flight to support Hillary's expedition, which presumably departed from Wigram. Even if Collins wasn't on that trip, the RNZAF base that he was attached to would have accumulated some institutional knowledge of sector whiteout. Further, there is no reason why the same thing can't occur in the Southern Alps, not far from Wigram.

The point is that Collins may well have known about sector whiteout, hence the comment he made at 18000 feet. This makes his spur-of-the-moment decision to go down through that hole and fly VMC, thereby putting himself between the cloud and the ice, even more careless. The letters VMC do not sit easily with "very hard to tell the difference between the cloud and the ice".

[prospector]

Even if Collins wasn't on that trip, the RNZAF base that he was attached to would have accumulated some institutional knowledge of sector whiteout

I am quite sure that could be said of whiteout in the general term, but as Judge Greene said in his summing up when Gordon Vette gave his evidence in Washington expanding on his sector whiteout theory

Since Capt Vette was apparently the first person to have presented to experts in perceptual phsycology and to the world at large the theory of sector whiteout with respect to an aircraft in level flight the phenomenom was entirely unknown prior to the crash of FLT 901.

[Flt.Lt Zed]

Collins was a navigator. Mahon proved that he was a very good navigator. But he missed many subtle clues that would have made him a very good pilot.
Blame 50:50.

[DozyWannabe]

Originally Posted by ampan

The letters VMC do not sit easily with "very hard to tell the difference between the cloud and the ice".

The problem with that out-of-context clipping from the CVR is that it disregards the two unintelligible words immediately afterwards, as well as the unintelligible words in the previous sentence. Quoted from your post:

0018:11 – Captain: “Clouds come down a bit * * * may not be able to * * McMurdo. Very hard to tell the difference between the cloud and the ice * *”

It's true that your way of reading it is potentially valid, but equally as valid to my mind is the fact that at 16,000ft McMurdo Sound (and yes, McMurdo Station) would be obscured by the overcast below - and at 6,000ft they'd be right in the middle of the cloud and wouldn't be able to see anything (including Erebus). So at that point the only chance they had to follow their original flight plan would be to descend below the overcast, which they could only do with permission from Mac Central. Remember that sector whiteout is caused by refracted sunlight bouncing off the ice and the overcast - not the clouds themselves, which he is directly referring to.

So - on the understanding that this is a wild guess, but nevertheless a valid interpretation - it could be "Clouds come down a bit over Ross Island may not be able to visual ID McMurdo. Very hard to tell the difference between the cloud and the ice at 6,000".

@prospector - If Judge Greene had asked for testimony from the US military, RAAF and RNZAF pilots who went to McMurdo, then he'd have quickly discovered that while it was a relatively unknown thing on the line, it was a very regular occurrence down there.

[prospector]

@prospector - If Judge Greene had asked for testimony from the US military, RAAF and RNZAF pilots who went to McMurdo, then he'd have quickly discovered that while it was a relatively unknown thing on the line, it was a very regular occurrence down there.

Air New Zealand and CAA did liase with those operators, and that is why the approved let down area was as stated, and the minimum altitude was at 6,000ft. It may have been a regular occurence down there, but until Vette used it as an explanation as to why an aircraft flying VMC, with terrain obviously visible abeam and astern, could fly a perfectly serviceable aircraft into a mountain that everybody knew was there, it was called whiteout, Vette termed the phrase sector whiteout.

[DozyWannabe]

Vette may have brought it into common parlance, but the term existed in scientific circles before he began his investigation. The problem with your rigid interpretation of NZCA's rule is that it was knowingly flouted by ANZ on a regular basis and a dispensation to break it was given verbally at the very briefing attended by the crew.

To say they broke the CAA regulation in itself may arguably be technically correct, but in real-world terms the fact that they were given a dispensation to break it by a senior airline official means - to my mind - that the responsibility lies higher up the chain than the PIC on that occasion.

In the end the original finding of "pilot error" was based on certain assumptions that ranged from the dubious (that the briefed track went straight over Erebus) to the dead wrong (that they were in cloud when they crashed). Evidence that had as much potential to vindicate that conclusion as it did to scupper it was misplaced or destroyed - why?

[chris lz]

Basic principles

For pilots:

I still don't feel, despite the incredibly informative discussion, that I've completely graduated from Erebus 101. In previous posts I've made the assumption AINS is not as reliable as ground based navigation aids; and therefore is inadequate as a substitute for the purpose of a descent below MSA . Would all the pilots here agree with this? I believe the operative assumption of most pilots is "yes, it's not as reliable." If so, could one of you kindly spell it out in detail for us bystanders. Why specifically is it more dangerous? Is it the "drift" factor, the need to enter coordinates, or something else?

Thank You

[DozyWannabe]

@chris_lz:

I'll leave the technical discussion of procedure to the pilots, but the INS track was not used for the descent below MSA, which was offered by Mac Station under "radar vectors" and taken up under VMC rules by the crew. The INS track was re-engaged once they were at the assigned alititude, but this was probably only done to provide a guideline position as they re-checked their position visually (having checked and cross-checked on the descent to the best of their ability). Unfortunately the sector whiteout combined with their position gave them the impression that they were somewhere other than where they actually were - and the AINS track based on the changed co-ordinates meant that their backup plan (without their knowledge) had also been foiled.

[chris lz]

Originally Posted by DozyWannabe

the INS track was not used for the descent below MSA, which was offered by Mac Station under "radar vectors" and taken up under VMC rules by the crew.

Yes, I'm quite aware of that. But what I would ask you, and others who take the "Vette position" is, in the absence of AINS, do you really think the crew would have had the confidence they did?

Hypothetical: the crew is in a simulator with no information provided by AINS, but are told they are nearing the Antarctic coastline somewhere within a 50 mile radius of the general McMurdo Sound area. They are shown the same view out of the cockpit that existed that day as they approach the area of Ross Island. Would they be able to establish a "positive fix" in this situation?


Real flight Hypothetical: the AINS malfunctions and stops working some 100 miles out from the area, before any land has become visible. If they arrive over the same location as where their actual real life descent began, would they still be entitiled to a "positive fix."?

Do you see what I'm getting at?

[prospector]

Dozeywannabe,

You have made your position adequately clear, please do not keep making statements like

.

The INS track was re-engaged once they were at the assigned alititude,

It is, like a lot of your statements, completely without foundation.

You do not get an assigned altitude during a VMC descent, and you would never get assigned any altitude below MSA before you were identified by radar. And as has been proven beyond doubt, they were not on radar. Your theory of radar tapes being destroyed is farcical. It was physically impossible for the radar to get a line of sight return when they were behind Erebus and Ross Island.

But I thank you, I can now see why Mahon has so many adherents.
====================================================

Do you see what I'm getting at?

I can certainly see what you are getting at. Such a situation could develop, that is one of the reasons why the descent requirements were spelt out in such detail.

The positive fix was positively wrong.