Erebus 25 years on

[prospector]

We do know they were not expecting the track to take them directly at Erebus, they were expecting to be tracking down the flat surface of McMurdo Sound and that track was changed the night before without telling Collins and his crew

That in itself means nothing, if they could not confirm they were in the middle of McMurdo sound by means of the descent the captain requested, VMC, they could not legally confirm it with the AINS, it was not cleared for nav purposes below MSA. As no mention was made of Mt Erebus, apart from asking where it should be, or Mt Bird or even Ross Island during the descent, as recorded on the CVR, then one must assume they were not VMC and the only position line they had, the track they thought they were on, was certainly not enough. Surely the end result is sufficient proof of that?

[megan]

Nah, the government forked out my 6 bucks for me

You were obviously asleep during the lessons, and so wasted my tax payer dollar. I want a refund.

For those wondering about whiteout, the following is taken from Vette's book, of what various people with the necessary expertise had to say about the phenomena.

For any estimate of distance one needs to have cues. It is certainly true that one looking at rising snow slopes with the sun behind and cloud above could think that he perceived a 40 mile expanse of level ice. Without textures or contours he could see it as far, instead as close. He could also think that a snow slope was ground rising in perspective and therefore level to a horizon if he saw it rising. This would in part be due to his expectations if he did not see any rising which would purely be a matter of expectation. With cloud cover it could give the appearance of a horizon (and thus a rising). Of course, to the extent that cues actually existed the foregoing premises would progressively disappear.

Captain Philip T. Briska was interviewed on 31 October. He is a Flight Surgeon and Chief Opthalmologist at the Institute and is also a naval aviator with over 2,000 hours mostly on fighters, and over 150 carrier landings. He also has expertise as an accident investigator. A clear view was formed that he is a perceptive and practical man and his opinion is worthy of weight. (Doctor Goodson’s view is that of a pure scientist and is limited to what can happen).
Captain Briska has expressed the view that the flight crews must have seen Beaufort Island (unless it was concealed from them by cloud, of which there is no evidence). This would have occurred at the stage of their left hand turn and at the end of the northern leg. Such a turn would have been relatively slow and decorous for the comfort of the passengers, unlike the type of rapid turn which can be accomplished in a fighter, and he commented that the flight crew must have had their heads in the cockpit or asleep not to have seen it. He observed that they would be looking for land after coming down from altitude. He expressed the thought that what they saw was Dunlop Island, adjacent to the mainland, which would, of course, account for the observation "land ahead" and also reinforce the fallacious impression of their being further to the west. He appears to be of the school of thought that thinks the "bit thick here" is referring to somewhere other than the aircraft’s proposed track. He emphasized that the essence of VMC flying is to have adequate visual cues. If the Captain saw the land displayed in photographs 10 and 11, that would perhaps be consistent with his mental picture of his track as falling between Cape Bernacchi and Cape Bird. Seeing the cloud above the land to the left and right —- the land being in appropriate directions on his assumed track — this would confirm his sense of being on the appropriate track. lf the cloud base ahead was consistent with the 500 feet to left and the 1500-2000 feet to right described by the Meteorologists, and the cliffs were obscured by a fog ramp, thee may well have been ahead of him similar cloud layers. If the top cloud came down progressively in step with that to right and left (here it is essential to have reference to the local patterns in this regard) and if there was a fog ramp obscuring the cliffs, there would have been a cloud free area ahead; though this would be difficult to distinguish from actual cloud. On the basis of a belief to be overflying sea ice and that there was a 40 mile visibility below the overcast from McMurdo in his direction, it is possible that he would believe himself to be seeing a sea ice ahead with a gap above the cloud: this being, in fact, the slope of Mt Erebus.

The ‘light bounce’ or (less probably) empty space myopia, may have aggravated such misconceptions; to which the absence of adequate visual cues would also contribute.

Because of the factors inducing belief in a westerly path his brain could well be affirmed in its belief, even if there were some nonconformity in what he saw.

There is, however, a great degree of uncertainty when one approaches a cloud overcast as to its altitude and distance. This observation is not confined to Antarctic aviation but is quite general. Consequently it would be difficult to know — even in temperate conditions — whether VMC was being maintained or not.

This difficulty was no doubt aggravated by the Antarctic factors just referred to — that his absence of visual cues and (at present) the ‘light Bounce` phenomenon or (if present) empty space myopia.

Our interview with Captain Ginsburg was highly instructive. He is a world expert on illusory visual phenomena and was awarded a Ph.D. by the University of Cambridge in the United Kingdom for his work in this field. His work for the United States Air Force is, not unnaturally, directed towards, the special visual problems which may occur in the handling of fighter aircraft travelling at supersonic speeds.

We demonstrated to Captain Ginsburg a summary of the total information which we had obtained regarding the weather conditions at McMurdo at the relevant time, and he made himself thoroughly familiar with all this information. We also asked him to take into account, but only as an hypothesis, that Captain Collins had flown on nav. track southwards from Cape Hallett until orbiting through a cloud break and had armed the nav. track again as the last orbit concluded because of his belief that the nav. track would lead the aircraft down the centre of McMurdo Sound with many miles of flat sea or ice on either side.

First of all, Captain Ginsburg deferred his consideration of this latter evidence suggesting Captain Collins believed that by maintaining the nav. track he would be keeping the aircraft many miles away from any high ground. Captain Ginsburg concentrated his attention upon what the pilot and co-pilot were likely to have seen at the conclusion of the second orbit when the plane was locked back on to nav. track as it approached Ross Island. In Captain Ginsburg’s opinion, having regard to the known height of the overcast — which, judging by the passengers’ photographs was still well above the aircraft at the moment when it struck the mountain-side — and having regard to the position of the sun and its 34° inclination, then the pilot would have seen a white expanse of flat terrain extending forwards for an unlimited distance. His point of visual reference would only have been the shallow strips of black rock some miles to the left and some miles to the right of the aircraft, representing Cape Tennyson and Cape Bird.

Looking forward, there would be no points of reference over the ice and snow. Not only would there be no points of contrast but there would be no perception of depth. The fact that the flat white carpet in front was in fact rising upwards at an inclination of 13° and then 19° before meeting the overcast would not be perceived. There would be no shadows and no points of reference to terrain in a forward direction, and Captain Ginsburg expected that a pilot not familiar with this type of visual illusion would merely fly straight on.

We referred to the undisputed evidence that no one on the flight deck ever saw the snow-covered slopes into which the aircraft flew. Captain Ginsburg said that this was not a surprising feature at all and indeed he would expect, in the conditions prevailing, that no one on the flight deck, even flying in clear air, would detect that the aircraft was about to strike a rising expanse of white terrain.

He said that the only pilot or pilots who would detect that ocular phenomenon would be people who had flown in Polar regions before. He said that pilots with Arctic or Antarctic experience would also not see the mountainside but, having noted the overcast, would be aware that there might be something in front of them which they could not see. The two or three pieces of rock face in the ice cliff directly ahead of the aircraft would not be observed as anything but the black strips of sea of the type previously encountered.

We then asked Captain Ginsburg to consider the factor previously mentioned — namely, that the pilot may have believed himself to be flying over a very wide expanse of flat ice in the approximate centre of McMurdo Sound. Having studied the maps, Captain Ginsburg expressed the opinion that the two thin strips of dark rock to left and right of the approach to Lewis Bay would coincide, in the pilot’s opinion, with the entrance to McMurdo Sound, and if the Captain’s nav. track confirmed the pilot’s belief that he was in the centre of McMurdo Sound then the totality of the illusion would be. complete. He said that the pilot, upon levelling out after the second orbit, and upon looking far ahead along the flat white surface, would be expecting to see the high terrain 20-30 miles away which lies approximately to the true south of the head of the Sound, and when he could not see it he no doubt decided that it was safer to climb away. Overall, Captain Ginsburg was of the opinion, having studied all the evidence which we were able to give him, that the absence of depth and contrast definitions would have produced what he described as a characteristic example of visual deception.

Captain Ginsburg placed very considerable emphasis on the same point as had been made by Professor Day, namely that everything turns on the mental pre—condition of an observer. He stressed that the eye is not a camera. He said that the observation of a particular object necessarily requires a combination of the function of sight with the function of mental activity associated with the process of observation. Discrepancies between what appears to be seen and what is known to be visible are automatically cancelled out by the mind in favour of a picture of what is known to be there.
If Captain Collins believed, on various grounds, that he was flying down the approximate centre of McMurdo Sound then he would, as a necessary function of his intellect, relate whatever he saw to what he expected to see, and would co-ordinate objective and subjective perception. But this would only occur if he was certain of his position. If he were in any way uncertain of his position then his subjective perception would be disengaged, so to speak, and he would be guided by visual perception alone. If certain of his position, and his course, he would automatically discount minor variations in the visual perception as opposed to what he expected to see, but only up to a certain limit of tolerance, that is to say, if visual perception suddenly appeared to present a picture which was markedly different in some respect from his expected observation, then that factor would intrude upon the pre-condition of certainty of position and, for the first time, a state of mental uncertainty would arise as to whether he was in fact upon the course or in the position previously assumed.

In this respect, according to Captain Ginsburg, the similarity in the approach to Lewis Bay and the approach to the head of McMurdo Sound had constantly to be borne in mind because, judging from the passengers’ photographs, it was in all probability a factor confirming the mental set of Captain Collins that he was certainly in the centre of McMurdo Sound. It seemed clear from the passengers’ photographs that the tip of Cape Tennyson, as seen from an approach to Lewis Bay, and the tip of Cape Bird, as seen from the same position, each revealed a very shallow line of black rock surmounted by snow. If the appearance of Cape Bird from the centre of the Sound also presented a narrow strip of black rock at sea level, and if Cape Bernacchi presented a similar picture, then the inequalities of distance would not matter. There would not beany sufficiently obtruding difference from the expected vision sufficient to cause any doubt to arise.

Although out of sequence in the narrative, I should here refer to another expert opinion on this topic. On 10 November 1980 we visited Farnborough and, having there listened to a reproduction of extracts from the cockpit voice recorder tape (as hereinafter mentioned), we were asked to see Mr Roger Green who is a Psychologist employed in a civilian capacity with the Royal Air Force as a specialist in flight skills, including visual illusion. His attendance is required at about one-third of the Boards of Inquiry held by the Royal Air Force involving incidents in which the presence of human factors appears to have been an operative cause.

Mr Green laid stress upon the guides provided by visual cues, and emphasized the point that without visual cues the factors of depth and contrast substantially disappear. He gave by way of example a sudden snowfall over one of the military air-fields in England which resulted in three fighter pilots landing well short of a runway of which the location was very familiar to them. What had happened was that the snow had obliterated the visual cues by which they had been guided in previous approaches, and Mr Green stressed the point that in many cases people, and especially pilots, are not necessarily aware of the fact that they are using visual cues so that the disappearance of the latter passes unnoticed.

In snow-covered terrain, a pilot is deprived of texture information which will alone acquaint him with slope and distance. In bright sunshine he is only deprived of that information to a partial extent. But even so, his normal appreciation of variations in terrain is adversely affected. Mr Green also stressed the importance of the mental set of a pilot, and believed that Captain Vette’s comparison between Lewis Bay and the approach to McMurdo Sound was a good example.

Mr Green said that stereopsis and binocular cues are only of help up to relatively short distances, perhaps not exceeding 100 feet or so, and that thereafter perception depends very largely upon experience. It is for this reason that Mr Green placed the greatest stress upon the principle that there can be no substitute, in the aviation field, for past experience of terrain. An R.C.U. briefing should be confined, in Mr Green’s opinion, to purely conventional briefings. It cannot implant knowledge in the memory in the same manner as actual experience. He pointed out that a civil pilot does not often fly purely visually, and Mr Green was of the opinion that when this occurs and a pilot is unfamiliar with the terrain, a number of dangers will instantly arise.

The third of the experts whom we were advised to see was Mr G. W. Shannon, Vice-President of Operations for Bradley Air Services Limited of Ontario. Mr Shannon’s company flies both passenger and freight schedules up to North Canada and the sub-Arctic. He was also retained some years ago to carry out a commercial contract in Antarctica. He flew from the southernmost point of South America across to Shackleton Base in Antarctica, and then across the Polar Continent to McMurdo. This flight, and other operations in the Antarctic, was carried out in a de Havilland twin Otter, Mr Shannon’s work being connected with the operations of a United States drilling site. He is reasonably familiar with the McMurdo region by reason of that particular contract which he carried out in Antarctica. Mr Shannon was recommended to us as being an expert whose knowledge and experience of flying in snow conditions is exceptional.

We saw Mr Shannon at his company’s location at Nepean, some miles out of Ottawa. Mr Shannon had the advantage of having no prior knowledge of the DC-10 disaster, except that he naturally knew of the occurrence. He had not read the Chief Inspector’s Report, and had no detailed knowledge of the circumstances. Over a period of between two and three hours we displayed to Mr Shannon all the relevant maps and diagrams, weather information, cloud locations, passengers’ photographs and so forth. We also showed him the Chief Inspector’s transcription of the cockpit voice recorder. Mr Shannon noted all this material and paid close attention to the cockpit voice recorder transcript which he read and reread on a number of occasions, particularly the closing stages.

In Mr Shannon’s opinion, the prevailing weather and the location of the sun and the other factors previously mentioned would present to the pilot and co-pilot of the DC-10 a forward vista of flat snow and ice extending away to the far distance, and he had no doubt that a pilot unfamiliar with Polar conditions would believe that he was flying forward with clear visibility over flat terrain for many miles. Mr Shannon believes that the pilot and co-pilot would have therefore an apparent flat and clearly visible terrain definition, whereas in fact there would be no terrain definition at all.

We asked Mr Shannon whether the overcast extending forward would form an illusory horizon in the distance at a point where it met the snow-covered rising ground. Mr Shannon said he thought not. He said that in such conditions the almost invariable effect is that the under-side of the overcast turns white so that there would be no horizon at all. He said that there was a possibility of a false horizon, but he regarded that possibility as remote. His own years of experience of flying in such conditions led him to the conclusion stated above, namely, that the overcast in front of the pilot would seem to disappear by reason of the fact that its grey under-surface would become white in colour through the multiple light reflection provided by overhead sun behind the aircraft.

Mr Shannon gave as an example an occurrence which often takes place at their own airport when the ground is covered with snow. He said that if there is a light overcast overhead then in daylight the underside of the overcast turns white and it is not possible from the ground to discern the height of the overcast. He said you know the overcast is there because you cannot see the sun, but it is not possible to say whether the overcast is 1500 feet high or 5000 feet high when looking upwards from the ground. He said that they are dependent upon reports from pilots as to the height of the overcast.
Mr Shannon said that having regard to the known weather conditions which we had exhibited to him, he would expect that as Captain Collins levelled out following the second orbit, and having dropped height to 1500 feet to try and see something in the distance but without success, that Captain Collins would then have elected to climb away because he could not see any landmarks in the distance. Mr Shannon said he noted, from his study of the cockpit voice recorder transcript, that Captain Collins decided, very soon after having levelled out, that he should fly away and he attributed that decision to the fact that although the aircraft was {lying under the overcast, and although the ground seemed to stretch away for miles, nevertheless there was no terrain anywhere to be seen.

As with other witnesses whom we saw on our travels, Mr Shannon placed primary significance upon the adherence by Captain Collins to the nav. track. He said that if Captain Collins had plotted the nav. track on a map, then he would obviously have believed that there was no danger of any kind ahead, and that he was many miles away from any high ground. Mr Shannon said that one of the reasons why he had studied and re-studied the closing stages of the transcript was to try and see whether there was any expressed concern or doubt on the part of the pilot or co-pilot in relation to the course or position of the aircraft. Mr Shannon was not very interested in the cross-talk which was taking place behind the pilots. He said that he drew the conclusion that neither the pilot nor the co-pilot entertained the slightest apprehension at any stage, and he drew the further conclusion that each of them was perfectly satisfied as to the course and position of the aircraft.
We raised with Mr Shannon the theory that a pale fog may have drifted off the ice and covered the ice cliff. We told him that a helicopter which had landed on the ice shelf below the cliff about an hour later saw no sign of the ice fog although it was observed on subsequent days to be coming off the ice. Mr Shannon said that the winds in that area are very fickle, and even a temporary breeze from the true north would instantly form ice fog the moment it reached the ice shelf below the cliff. The fog might persist with a steady breeze, climbing upwards, but if the breeze died away then the fog would disperse. Mr Shannon believed that if there were patches of black rock visible forward of the aircraft on that part of the ice cliff not covered by glacial ice, then this would have no significance to Captain Collins or the co-pilot as, from a distance, any shallow patches of black rock would merely resemble the patches of black water which they had previously observed.
Mr Shannon said that the situation confronting Captain Collins as he levelled out after the last orbit would have signalled a red light to the experienced Antarctic flier who would immediately have flown away. Photograph no. 10 illustrates that the weather ahead was getting more solid, and in Mr Shannon’s view any experienced pilot would have realised that conditions were no longer appropriate for VMC flying. But Mr Shannon again pointed out that it had taken Captain Collins only a brief interval to reach that conclusion, and he had then attempted to fly away once he could not discern the clear visibility which Mac Centre had told him would be apparent once he had descended to 2,000 feet.

[ampan]

At least us storytellers tell a similar story. The believers are all over the place. They started out boldly going where on-one's gone before, with a claim that they the pilot was VMC when he hit the mountain. Now it's 'we don't know' / 'we weren't there' / 'we couldn't see what he saw'. We might not be able to see what he saw, but we can make some pretty accurate assumptions. There's no evidence of a murder-suicide, so the captain could not have seen the mountain. Compressor Stall has postulated, taking the view out the side as shown in the photos, that known black rocky outcrops would have been visible from more than 8km away. Assuming all of that is true, I again, on behalf of the storytellers, ask of the believers whether the captain was, in fact, VMC when he hit the mountain or, if not, whether he genuinely believed he was.

[prospector]

Quote:

Further to the points under discussion, an article in todays Dominion Post about the accident quotes the conversation that a Ted Robinson (deputy leader, Scott Base) had with Jim Collins.

Robinson, was at the time, sitting in the radio room doing routine checks with field parties when Collins called for a chat and a weather report.

Quote "Collins made contact and I informed him of the weather conditions, how it was a complete whiteout". He, Robinson, told Collins that it would be unwise to come to McMurdo as passengers wouldn't see anything.

He suggested that Collins fly over the Dry Valleys where the weather was clear.
Robinson also told Collins that a work party on the sea ice some 64 kms from Scott base and at Vanda Station had clear conditions.

Shortly after Collins accepted that information he changed frequency to McMurdo station and Robinson did not speak with him again.
Robinson was never called to give evidence at the enquiry.

What your post tells me is that anybody who would not testify along the many lines you have posted, the following line is the most important, and from someone actually there at the time, as Deputy Leader Scott Base he would certainly have been as qualified as any that Vette quoted.

Robinson was never called to give evidence at the enquiry.

.

.

[3 Holer]

Thank you ampan and prospector, you never fail to deliver.

So now we can continue to assume, presume, guess, etc,.etc,. Boring isn't it.

That's me! 3 Holer

.....then one must assume they were not VMC.....

That's prospector #1181

.....but we can make some pretty accurate assumptions......AND
Assuming all of that is true,...

That's ampan #1183.

The only one's without assumptions and presumptions appear to be megan and compressor stall.

[ampan]

The assumptions being made are in your faction's favour, pursuant to what is known as a hypothetical question.


I don't do emojis, but just out of interest, which the things on the right is a chicken clucking?

[megan]

with a claim that they the pilot was VMC when he hit the mountain

Morons don't come any bigger than you ampan. Whiteout is no different to blackout, just the reverse of the phenomena. Did you look at the Aero Commander video flying into the side of a mountain I posted earlier? It was night VMC, but he couldn't see the mountain, and thus flew into it. Collins was faced with the exact same predicament, except in his case it was whiteout.

Have a read up on requirements for night VMC to get a feeling for what should have been in place for the Antarctic VMC flights.

If you want some one to blame, it was the prat who dreamt up the idea of scenic flights in VMC below the MSA.

[Hempy]

Originally Posted by megan

Morons don't come any bigger than you ampan.

Keyboard warrior. $100 says you wouldn't have the nuts to say that to his face.

Did you look at the Aero Commander video flying into the side of a mountain I posted earlier? It was night VMC, but he couldn't see the mountain, and thus flew into it.

So what? Pilot error. What was the Aerocommander pilot doing below the MSA when he couldn't visually separate himself from terrain? Doing a 'scenic'?

That's moronic.

[megan]

Keyboard warrior. $100 says you wouldn't have the nuts to say that to his face.

You better bet I would. You are a noted keyboard warrior yourself, particularly on JB. Arrogant, talking down to people, and I wonder if your tag comes from what you smoke.

What was the Aerocommander pilot doing below the MSA when he couldn't visually separate himself from terrain?

Pity you don't do accident reports, otherwise you would know how it all came about, and he wasn't doing a scenic.

That's moronic

Nope, what is moronic is not learning from those that go before. You're not going to live long enough to make all the mistakes yourself. The trick is to fill your bag of experience without emptying the bag of luck.

[PapaHotel6]

So you've never flown to Antarctica before, but you get sent down there to do a sightseeing flight. The target area is covered in a low overcast. You get offered and accept a radar letdown, but then elect to descend VMC down to 2000' then 1500' presumably because of failure to establish VHF comms (without really discussing it with the wider crew). You don't plot your position beforehand, nor even mention the multiple sources of high terrain known to be in the area. Your flight engineer asks "where's Erebus in relation to us/I'm just thinking about high ground in the area". This doesn't elicit a response from yourself or your F/O. At 1500' faced with whiteout conditions you fly on for two minutes having recently mentioned "it's hard to tell the difference between cloud and ice". Then you crash your aircraft into the ground on Ross Island with the loss of 257 lives.

Megan said

what is moronic is not learning from those that go before.

So megan - you are either saying there is nothing to be learned from the actions of this flight crew as described above, or are calling yourself a moron. Which is it?

[megan]

PapaHotel6, goodday Ace. I'll take my lead from Gordon Vette when he said, "When I flew visually in the Antarctic I believed that there was no problem. Prior to my research on the Antarctic crash, I would have scoffed at this requirement. I am now firmly convinced that under certain lighting conditions an aircrew could fly into terrain, even with the terrain in the field of view and with plenty of time to take avoiding action. Therefore descent below the top of Mount Erebus, or other polar terrain, even in clear conditions, is hazardous. It appears to me that those of us who conducted the Antarctic flights may unwittingly have exposed ourselves, our passengers and crew, to a similar danger".

I don't have the arrogance to presume that I would not have been suckered given ANZ modus operandi.

Answer the question, why do QF scenic flight remain at the MSA. Because Collins screwed up, or because the entire enterprise of operating below the MSA was moronic? There can only be one answer.

[PapaHotel6]

No megan, that's not what I asked. I listed the actions in the cockpit without conclusion or extrapolation (I forgot to mention repeatedly arming the INS during VFR flight too) . Either you say there is nothing to be learned from those actions, and you might well have done *exactly* the same yourself; or you are a moron. Which is it??

Answer the question, why do QF scenic flight remain at the MSA.

Because that is how they've decided to operate their flights. Whereas Air New Zealand decided VFR sightseeing below MSA was okay once south of Mt. Erebus. Oh and also - I've never flown for QF, but from the outside looking in they seem to be the more professional outfit on every level *flame troll*

[Hempy]

Originally Posted by megan

You better bet I would.

Let me know when you two hook up. It'd be interesting watching you trying to mumble whilst spitting out teeth.

Originally Posted by megan

You are a noted keyboard warrior yourself, particularly on JB. Arrogant, talking down to people

Ah Jetblast, the home of right winged vitriol. Hence why I retired from posting there.

It's a good fit for you though, away from the 'professional' boards and off with the Walts, wannabes and spotters.

Originally Posted by megan

I wonder if your tag comes from what you smoke.

Actually, it's a contraction of my surname. It's a fairly de rigueur way of attaining a nick name in Australia. I can guess how you got yours.

Originally Posted by megan

Pity you don't do accident reports

Not sure what you mean by that. Is that 'cool' talk?

Actually I have done 'accident reports'. Written more than one.

I suggest you go and have a nice Bex and a lie down before you have an attack of the vapours. People disagreeing with you doesn't seem to agree with you.

[ampan]

I don’t want to fight megan. Firstly, despite the name I don’t think he’s a girl. Also, he’s probably a lot younger than I am. Finally, I recently suffered an injury in a typing accident.


But back to the argument. At #1187, megan reacts like a frightened octopus. There’s plenty of ink, but no answer to the question. Methinks that the believers should give up on this VMC point and move on to their real argument, which is that the poor captain was led astray by his negligent employerand that he had little inkling of the dangers lurking below the cloud.

[prospector]

megan,

Please explain what your take is on the requirements for VMC flight, as posted by yourself way back:

regs in force at the time state 8Km vis, 1 mile horizontally & 1,000 feet vertically.

It has been established beyond doubt that for these ice flights the vis has been amended to read 20km.

How is it possible to be 1,000ft vertically from cloud when after descending to 2,000ft you have to go down to 1,500ft to see further in?.

A minor point granted but after all the other minor points being discussed, perhaps an opinion on what was legal and what was not is in order.

[3 Holer]

.....because the entire enterprise of operating below the MSA was moronic......

100% correct megan, just another example of “the incompetent administrative airline procedures which made the Erebus disaster possible.”

[prospector]

.

100% correct megan, just another example of “the incompetent administrative airline procedures which made the Erebus disaster possible.”

The requirements for operating below MSA were clearly laid down, if they were complied with there would have been no disaster.

Would you please give answer to a question I have asked a number of times, but never had an answer to.

How could the airline and CAA be totally responsible for this disaster?

Nothing was programmed below MSA, that was the Captain and crew decision, or as appears to be the case here, the Captains decision taken with no discussion between the crew?

These were not sprog pilots, they were well seasoned airline captains, surely the company was allowed to trust them for decision making regarding complying with instructions, and if they went outside these instructions then there would have to had been good justification.?

.

[megan]

It has been established beyond doubt that for these ice flights the vis has been amended to read 20km.

How is it possible to be 1,000ft vertically from cloud when after descending to 2,000ft you have to go down to 1,500ft to see further in?.

It is not entirely clear that flight by civil aircraft within the McMurdo airspace was considered "Controlled" or "Uncontrolled". On 13 October 1977 the Commander of the USN Support Force in Antarctica advised in a message (No. 3100) to CAD Christchurch

AIR TRAFFIC CONTROL/FLIGHT FOLLOWING SHALL TAKE THE FORM OF LOCATION ADVISORY OF DEEP FREEZE AIRCRAFT AND POSITION REPORT RELAY ONLY.

Chippindale questioned the briefing failing to mention,

The authority of the US Navy’s Antarctic ATC system to control the civilian Air New Zealand flight.

It would seem quite explicit from the USN message that they would not be providing positive control, hence flight by civil aircraft could be deemed to be in uncontrolled airspace. As with all Deep Freeze functions, it was "use at your own risk" for civilians.

On that assumption, the only element of the VMC rules altered was the visibility requirement increased from 5 km to 20 km. The other rules pertaining would have been below 3,000 AMSL or 1,000 AGL, whichever is higher, you only need to remain clear of cloud and in sight of ground or water.

[capt.cynical]

pedantics

Sheeeesh 60 pages going round in circles. !!

[prospector]

Yes, but, as was discussed earlier the descent was to be coordinated with McMurdo radar, not controlled by McMurdo radar. To even coordinate they would have had to have been identified.

The other descent requirements re 20DME from the TACAN and to the South of McMurdo would have, as planned kept them well clear of Mt Erebus.

There would have been a cone overhead the radar when no return would have been possible, but the radar operator would have known that, and it was nowhere near Ross Island and there for Mt Erebus.

The other rules pertaining would have been below 3,000 AMSL or 1,000 AGL, whichever is higher, you only need to remain clear of cloud and in sight of ground or water.

I do not think anybody in their right mind would consider these requirements could be applied to a DC10 at 260kts 1,500ft, anywhere, let alone in Antarctica in the weather conditions prevailing in McMurdo Sound, and what they had been advised was current at Scott Base, or any other sightseeing position on their agenda at McMurdo