Paul Holmes and Erebus
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Originally Posted by prospector
The positive fix was positively wrong.
Thanks
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One should know the error rate of AINS, but it is a variable that cannot be checked until a ground based aid at a known fixed point is interrogated.
A ground based radar will have a system whereby its integrity can be ascertained with certainty, and will be regularly calibrated. The actual radar at McMurdo was normally only used for approaches. the maximum elevation was from memory only 30 degrees. If it was to be used as a surveillance radar it involved a considerable amount of adjusting.
In saying this I admit my exposure to AINS was limited to a couple of demonstrations of its capabilities whilst in the jump seat of a DC10 on a couple of long haul runs. Only the elite fleets were supplied with such state of the art equipment at that time.
It was the visual positive fix that was wrong., thus illustrating why the descent requirements were as they were.
A ground based radar will have a system whereby its integrity can be ascertained with certainty, and will be regularly calibrated. The actual radar at McMurdo was normally only used for approaches. the maximum elevation was from memory only 30 degrees. If it was to be used as a surveillance radar it involved a considerable amount of adjusting.
In saying this I admit my exposure to AINS was limited to a couple of demonstrations of its capabilities whilst in the jump seat of a DC10 on a couple of long haul runs. Only the elite fleets were supplied with such state of the art equipment at that time.
It was the visual positive fix that was wrong., thus illustrating why the descent requirements were as they were.
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DozyWannabe: You are right, it is not a good reason, it is a very bad reason and does not stand up to even a superficial examination.
It implies the radar controller did not know the position of the high ground in the area.
It implies the radar controller did not know the position of the high ground in the area.
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Originally Posted by prospector
One should know the error rate of AINS, but it is a variable that cannot be checked until a ground based aid at a known fixed point is interrogated.
1) AINS is inherently less trustworthy than ground aids
2) The primary reason is because ground aids are calibrated regularly.
3) Therefore, AINS should not be used a substitute for such ground aids.
I'm just trying to be extra careful here because it is these subtleties upon which many assumptions hinge.
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chris lz,
I would say so. It was developed for long range navigation, and was certainly trustworthy enough for that task. But I have never heard of an AINS approach to land procedure.
That would be fair comment Normally if there is any problem with the aid it will stop transmitting its identity code and cannot then be used.
Not for a let down below route MSA, especially not after a long time without any ground based aids to confirm its reading, and any doubt as to a visual positive fix.
1) AINS is inherently less trustworthy than ground aids
2) The primary reason is because ground aids are calibrated regularly.
3) Therefore, AINS should not be used a substitute for such ground aids
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.
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 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.
Totally.
In this case they performed all the necessary checks
Here is a question that might help you understand my viewpoint;
When the aircraft requested and recieved a descent VMC, who was responsible for separating it from terrain?
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@chris_lz:
I'll try to answer, but I think we're getting several hypotheticals away from relevant...
The answer to your first question depends entirely on how they navigated down there in the first place without INS (and given that the trips relied on INS to some extent to get them in the ballpark because the previous onboard navaids were not accurate enough it makes it extremely hypothetical as a situation). The only way I could see them doing it would be if they had a fully-qualified and dedicated navigator onboard, which would place the onus on the crew in any case. The computerised flight plans were sold as a safety measure as well as a cost-saving measure, but if you don't do it right then it means responsibility for navigation errors travels further up the chain than it did in the past (something that the regulations at the time did not recognise).
As far as your second question goes, I think they'd have turned back as soon as they positively identified an AINS fault.
@henry crun - Doesn't mean it didn't happen that way.
@framer - I phrased it badly (late night, sloppy thinking). I should have said it is *one* of the reasons. One of many others is that the crew had every right to do what they did on the basis of what they had been told by their superiors and nav section. The misidentification was partly down to rotten luck, which you can't do much about - but it was also partly down to very sloppy communication and organisation on the part of ANZ, which something could very much be done about. The pilots made a misidentification visually, but Vette's research proved that this was understandable and in my opinion (along with many others) this negates any idea that they should carry any blame. But there should have been safeguards - two of which were the radar station and the INS track. The failure to effectively communicate the change in planned track to the radar station or the crew lies squarely in ANZ's court. Had they done either or both of those things then in all probability the accident would never have happened.
That said, you may call it emotional - but it's valid in terms of verbal and conceptual reasoning as well. If ANZ had as much faith in the "pilot error" finding based on strict adherence to rules in the way that prospector, ampan and yourself seem to, then why behave in a manner that made it look like they had something to hide? It doesn't make sense.
Remember that Chippindale (and indeed Collins') RNZAF experience was more like 50-60 years ago, when military ops were a very different beast indeed (even airline crews carried full-time navigators back then!).
We've been over this before, but just because the rules state that the pilot is responsible for navigation under VMC rules, it does not automatically follow that the pilot should be blamed for an accident if one or more outside factors for which they are not prepared are the root cause of said misidentification. Hypothetically, if the flight was navigated DR from Auckland and they wound up in the wrong place after going VMC, then yes, some blame would be attached to the crew - but in this case the VMC starting point was supplied by a third party and it was not the starting point the crew expected, because they third party failed to inform either the crew or the radar station that approved the let-down that the starting point had changed.
I'll try to answer, but I think we're getting several hypotheticals away from relevant...
The answer to your first question depends entirely on how they navigated down there in the first place without INS (and given that the trips relied on INS to some extent to get them in the ballpark because the previous onboard navaids were not accurate enough it makes it extremely hypothetical as a situation). The only way I could see them doing it would be if they had a fully-qualified and dedicated navigator onboard, which would place the onus on the crew in any case. The computerised flight plans were sold as a safety measure as well as a cost-saving measure, but if you don't do it right then it means responsibility for navigation errors travels further up the chain than it did in the past (something that the regulations at the time did not recognise).
As far as your second question goes, I think they'd have turned back as soon as they positively identified an AINS fault.
@henry crun - Doesn't mean it didn't happen that way.
@framer - I phrased it badly (late night, sloppy thinking). I should have said it is *one* of the reasons. One of many others is that the crew had every right to do what they did on the basis of what they had been told by their superiors and nav section. The misidentification was partly down to rotten luck, which you can't do much about - but it was also partly down to very sloppy communication and organisation on the part of ANZ, which something could very much be done about. The pilots made a misidentification visually, but Vette's research proved that this was understandable and in my opinion (along with many others) this negates any idea that they should carry any blame. But there should have been safeguards - two of which were the radar station and the INS track. The failure to effectively communicate the change in planned track to the radar station or the crew lies squarely in ANZ's court. Had they done either or both of those things then in all probability the accident would never have happened.
That said, you may call it emotional - but it's valid in terms of verbal and conceptual reasoning as well. If ANZ had as much faith in the "pilot error" finding based on strict adherence to rules in the way that prospector, ampan and yourself seem to, then why behave in a manner that made it look like they had something to hide? It doesn't make sense.
Remember that Chippindale (and indeed Collins') RNZAF experience was more like 50-60 years ago, when military ops were a very different beast indeed (even airline crews carried full-time navigators back then!).
We've been over this before, but just because the rules state that the pilot is responsible for navigation under VMC rules, it does not automatically follow that the pilot should be blamed for an accident if one or more outside factors for which they are not prepared are the root cause of said misidentification. Hypothetically, if the flight was navigated DR from Auckland and they wound up in the wrong place after going VMC, then yes, some blame would be attached to the crew - but in this case the VMC starting point was supplied by a third party and it was not the starting point the crew expected, because they third party failed to inform either the crew or the radar station that approved the let-down that the starting point had changed.
Last edited by DozyWannabe; 14th Dec 2011 at 15:01.
We've been over this before, but just because the rules state that the pilot is responsible for navigation under VMC rules, it does not automatically follow that the pilot should be blamed for an accident if one or more outside factors for which they are not prepared are the root cause of said misidentification.
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There wouldn't even be an argument if those in your camp didn't want complete absolution of responsibility for the crew...
...who flew a servicable heavy jet at 1500ft, 250kts, below MSA, in a foreign environment, while navigating visually ... after the met service had told them that the cloud was broken at 2000ft and there were snow showers in the area.
Complete absolution is too much. It would be a very dangerous day for airline travel the day that the P in C didn't hold some responsibility for doing that.
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AirNZ didn't tell him to fly down that hole. He made that decision all by himself, on a whim.
He started the day by not noticing that the 166E he punched in (or read out) was not the 164E he had plotted the night before. He didn't check the waypoint on the way down, probably assuming blue skies. When he didn't get those conditions and was going to go somewhere else, he was offered the radar letdown, and accepted. So that was the plan: Stay above MSA until the ground radar has confirmed the aircraft's position, then descend. With that plan, the position of the waypoint was not critical. If he had stuck to the plan, the aircraft would have flown over the summit of Erebus, whereupon the VMC radio would have burst into life. But then, about 40 miles out, he spots the sea ice through a hole in the cloud, and very shortly thereafter, he's orbiting down through it. So he dumped a good plan, with hardly any discussion with the rest of the crew, and replaced it with a very bad one, namely, his VMC/AINS plan. VMC below the cloud could not be assured, nor could the position of the waypoint, which was now critical. At that point, things on the flightdeck would have become very busy, hence the sounds of paper-shuffling and the references to high ground. This was probably why they did not notice that Beaufort Island was not where it was supposed to be, despite going past it three times.
He started the day by not noticing that the 166E he punched in (or read out) was not the 164E he had plotted the night before. He didn't check the waypoint on the way down, probably assuming blue skies. When he didn't get those conditions and was going to go somewhere else, he was offered the radar letdown, and accepted. So that was the plan: Stay above MSA until the ground radar has confirmed the aircraft's position, then descend. With that plan, the position of the waypoint was not critical. If he had stuck to the plan, the aircraft would have flown over the summit of Erebus, whereupon the VMC radio would have burst into life. But then, about 40 miles out, he spots the sea ice through a hole in the cloud, and very shortly thereafter, he's orbiting down through it. So he dumped a good plan, with hardly any discussion with the rest of the crew, and replaced it with a very bad one, namely, his VMC/AINS plan. VMC below the cloud could not be assured, nor could the position of the waypoint, which was now critical. At that point, things on the flightdeck would have become very busy, hence the sounds of paper-shuffling and the references to high ground. This was probably why they did not notice that Beaufort Island was not where it was supposed to be, despite going past it three times.
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DozyWannabe: If I correctly understand what you are saying, a VMC descent required radar identification.
In that case, knowing that they were not identified, why did they descend ?
In that case, knowing that they were not identified, why did they descend ?
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One point that no one has yet brought up.
One of the reasons, apart to avoid whiteout, that the MDA (minimum descent altitude) was set at 6,000ft was to avoid any problem with bird strike. There are many skua gulls around McMurdo, as was witnessed by the people who had to clear the wreck. If a flock of skua gulls was encountered at 1,500ft, at 260kts, the damage sustained would be considerable. These are big birds.
The flights that did go down to this altitude, 1,500ft, at the invitation of the ice controller would certainly have been at risk of such a bird strike.
The sightseeing value of such a low level at that speed, when only a small proportion of the pax would have a window view is questionable.
One is left with the thought of for whose benefit were these low level runs carried out??
One of the reasons, apart to avoid whiteout, that the MDA (minimum descent altitude) was set at 6,000ft was to avoid any problem with bird strike. There are many skua gulls around McMurdo, as was witnessed by the people who had to clear the wreck. If a flock of skua gulls was encountered at 1,500ft, at 260kts, the damage sustained would be considerable. These are big birds.
The flights that did go down to this altitude, 1,500ft, at the invitation of the ice controller would certainly have been at risk of such a bird strike.
The sightseeing value of such a low level at that speed, when only a small proportion of the pax would have a window view is questionable.
One is left with the thought of for whose benefit were these low level runs carried out??
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@henry crun, ampan :
I think they thought they were identified on radar, as the transponder was coding before the letdown began (and probably during to some extent) - and that the offer to descend from the controller confirmed it.
@prospector :
ANZ only sold the outer rows of the aircraft on the Antarctic flights in order to make moving about the cabin easier - you can see this in the various films and videos taken for promotional purposes, and by the passengers (including one from the accident flight which is very eerie to watch).
Will pick up the rest tomorrow.
I think they thought they were identified on radar, as the transponder was coding before the letdown began (and probably during to some extent) - and that the offer to descend from the controller confirmed it.
@prospector :
ANZ only sold the outer rows of the aircraft on the Antarctic flights in order to make moving about the cabin easier - you can see this in the various films and videos taken for promotional purposes, and by the passengers (including one from the accident flight which is very eerie to watch).
Will pick up the rest tomorrow.
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0028:47 - F/O: "You didn't get the Tower did you?"
Capt: "No, negative, no we haven't got it"
...
0031:20 - Capt: "If you can get HF contact tell him that, we'd like a further decent - we have contact with the ground and we could if necessary descend doing an orbit."
0032:22 - Capt: "I'll come round there and set that down (at) ten thousand"
...
0035:15 - F/O: "Transponder is now responding"
Capt: "OK"
0036:32 - F/O: "We've lost him again"
...
[down to 1500 feet]
00048:55 - Capt: "Have we got them on the tower?"
F/O: "No - - - I'll try again"
0049:25 - Capt: "Have you got anything from him?"
F/O: "No"
Capt: "No, negative, no we haven't got it"
...
0031:20 - Capt: "If you can get HF contact tell him that, we'd like a further decent - we have contact with the ground and we could if necessary descend doing an orbit."
0032:22 - Capt: "I'll come round there and set that down (at) ten thousand"
...
0035:15 - F/O: "Transponder is now responding"
Capt: "OK"
0036:32 - F/O: "We've lost him again"
...
[down to 1500 feet]
00048:55 - Capt: "Have we got them on the tower?"
F/O: "No - - - I'll try again"
0049:25 - Capt: "Have you got anything from him?"
F/O: "No"
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DozyWannabe; There is no room for assumptions with something as important as radar identification.
You are either identified or you are not; and at no time was Collins advised he was.
You are either identified or you are not; and at no time was Collins advised he was.
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prospector,
I appreciate your detailed response to AINS.
What I'm hearing you say is, the crew was for all intents and purposes relying, by the back door route, on AINS. Take away AINS and you have a crew that would not have been confident that a faint patch of darkness was the west coast of Ross Island. Is that a fair statement?
I appreciate your detailed response to AINS.
Originally Posted by DozyWannabe
The answer to your first question depends entirely on how they navigated down there in the first place without INS (and given that the trips relied on INS to some extent to get them in the ballpark because the previous onboard navaids were not accurate enough it makes it extremely hypothetical as a situation). The only way I could see them doing it would be if they had a fully-qualified and dedicated navigator onboard, which would place the onus on the crew in any case.
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@prospector - The DC-10 had a theoretical maximum capacity of 380 passengers. Even if we knock some off so it's not all cattle-class , you're looking at about 330-350, which leaves 103-123 seats free from your stated number of 237. It was deliberate policy to "underbook" the Antarctic flights because to fill the central rows would impede cabin movement, as I said, and there's no point in going on a sightseeing flight and sitting in the central row!
The DC-10 may not have had the carrying capacity of a 747, but it was still a sodding huge airliner!
@chris_lz - No I wouldn't, but let me think about it a bit.
@ampan - Let me do a bit of digging to check. First thoughts - "him" could refer to the controller, but the transponder could still be coding.
The DC-10 may not have had the carrying capacity of a 747, but it was still a sodding huge airliner!
@chris_lz - No I wouldn't, but let me think about it a bit.
@ampan - Let me do a bit of digging to check. First thoughts - "him" could refer to the controller, but the transponder could still be coding.
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Whole transcript here (Annex C):
Chippindale Report
The point is that he was going down the hole before the transponder started. At the time that occured, the aircraft was descending from 13000 feet to 10000 feet, already well under MSA. So he definitely ditched the plan.
Vette's attempted explanation is difficult to fathom:
Chippindale Report
The point is that he was going down the hole before the transponder started. At the time that occured, the aircraft was descending from 13000 feet to 10000 feet, already well under MSA. So he definitely ditched the plan.
Vette's attempted explanation is difficult to fathom:
"There was a nagging doubt at the back of Jim Collins' mind, possibly associated with the briefing, that the approach radar would be unable to pick them up above 6000 feet." (Impact Erebus, p130)
There is no evidence of anything like that being said at the briefing, and it would make no sense. The whole point of the radar was to confirm an aircraft's position before it went below MSA."A quick mental reckoning put him about ten minutes before the McMurdo Sound waypoint near the Dailey Islands if he continued on the same heading, holding the same height. But there was no point in the exercise. The edge of the main cloud front was drawing closer and he would have to get beneath it before he could make the dog's-leg turn to hook in to the south of the island, and fly visually under radar guidance to the ice runway and the TACAN." (p132)
No point in the exercise? What's wrong with staying above MSA until his position was confirmed by radar, turning left towards Mac Station, and descending through the cloud base under radar guidance? After all, that was how the military pilots did it.