Originally Posted by
chris lz
"This is Cape Bird" I assume was made after the aircraft had descended below 6,000 ft?
Yes, it was during the "below cloud" phase of the flight - shortly before the crash. Crucially, if "This is Cape Bird" was what was said, it gives the lie to Chippindale and Thompson's assertions that the crew were not checking their progress against a map and contradicts Chippindale's belief that they were in cloud.
My question is, was it safe to rely on INS for this very descent? The view has been expressed that Collins and his crew should have positively identified the terrain before descending, or else wait for corroboration from ground instruments. That's the piece I'm trying to get a definitive answer on.
It was safe as long as the aircraft was following Chief Navigator Hewitt's "erroneous" co-ordinates, which were actually safer than the original path he plotted to the TACAN south of Ross Island. It was ANZ's practice to brief the next two Antarctic crews in advance, meaning that a period of time of four weeks would elapse before the second crew made the flight they were being briefed on. Captain Collins and Captain Simpson's crews attended the same briefing, and both received the same briefing materials which showed the route down McMurdo Sound - not just the publicity material, but a photocopied chart based on data from the navigation computer ostensibly from the navigation section. However, Hewitt testified that he had never seen that chart prior to the inquiry. On his flight, Simpson noticed that there was a discrepancy of 26 miles between where the McMurdo co-ordinates were plotted and where he could clearly see the station to the east and duly reported this to the nav section. Hewitt claimed that he believed he was correcting a .2 degree error, from the McMurdo NDB co-ordinates themselves to the TACAN as originally specified when the Antarctic flights began, but he failed to take into account his original typing error, turning a 2 mile discrepancy into a 26-mile discrepancy.
The chart showing the route down McMurdo Sound, and the INS co-ordinates following that route had by this time been in the system for a year - all the line pilots flying to Antarctica believed that the route change was deliberate, and that henceforth they would be flying down McMurdo Sound. All the evidence indicates that Collins' briefing materials showed the same thing (although ANZ's later conduct made sure that it could never be proven conclusively). If Hewitt had spotted the magnitude of his error and informed ops, the crash wouldn't have happened - in fact the flight probably would have been postponed while they sorted the error out. Likewise, if Hewitt had waited until after the Collins flight to make the correction, the next briefings would have been done with the new material and it's possible no-one would have been the wiser.
As for the conditions at the time, a lot of myth has grown up around that over the years - Chippindale went to his grave believing they were in cloud at the time, even though the photos recovered show visibility of 40 miles plus right up until the point of impact. But as Captain Vette's research showed, there was more to it than that.
Originally Posted by
Biggles78
At that time the 1953 Civil Aviation Regulations, Reg 51 stated "The Pilot in Command is responsible for the safety of the passangers, crew and aircraft".
Ah, but in 1953 it was technically impossible to send a jet full of people to Antarctica and back, and here we get back to an age-old problem of the reality on the ground overtaking the regulations. In 1953 (and for a decade to come or more), any Empire or Commonwealth operation would be carrying a full-time navigator on board and they'd be plotting the routes manually against charts every step of the way, informing the PIC if there were any changes. By 1979, nav section were desk jockeys working at computer terminals.
Collins was the Pilot in Command and the majority of the blame rests on his shoulders irrespective of the orchistrated litiney of lies by ANZ, it was HIS responsibility to check the waypoints that were input into the INS.
...
Captain Collins was responsible for checking the Flight Plan and using an old school atlas was really not the way to do that. That was not a professional at work on this ocassion and added to the swiss cheese slices.
All evidence suggests that he was not using the atlas for his primary route planning - he had the McMurdo route ostensibly given to him by nav section in his briefing materials along with a black-and-white photocopy of the chart. It looks like the purpose the atlas served was to cross-check the co-ordinates he was given at the briefing, and if he'd been informed that the co-ordinates had changed even slightly the following morning, there's no reason to suggest he wouldn't have checked them for a fourth time and discovered the error - in fact Captain Vette seems certain that he would have, having known him for two decades or more.
TVNZ's "Erebus : The Aftermath" docudrama has been removed from YouTube, which is a shame. However, NZALPA recently uploaded Captain Vette's "Impact Erebus" documentary in it's entirety - it goes even further than the Mahon report in places in terms of demonstrating the false visual perceptions, and mentions a couple of factors that the docudrama did not, which I consider very important - namely:
- The transponder indicator light on the flight deck indicated coding during the descent and approach to Erebus, giving the crew the impression that McMurdo were tracking them on radar and had them in the right position.
- The flight plan filed with McMurdo had the co-ordinates for the McMurdo waypoint removed and replaced with the term "MCMURDO" - the only time this had happened in the entire time ANZ had been flying down there.
It also says that the briefing on whiteout given to all ANZ crews was inappropriate for aviation, instead being based on the effects of what are commonly known as snowblindness - the dangers of a low overcast obscuring high ground and possibly (although Mahon was not convinced) presenting a false horizon were never covered - this was Mahon's "malevolent trick of the polar light".
Part one is here:
To answer the question chris_lz is asking regarding "positively identif[ying] terrain", a combination of the features of McMurdo Sound versus Lewis Bay shows that it would indeed be easy to mistake one for the other were Erebus to be obscured. Cape Tennyson is approximately the same distance and azimuth from the track over Erebus as Cape Bird is from the track down McMurdo Sound. The cliffs to the west of McMurdo Sound (Cape Bernacchi) are three times further from the McMurdo track than Cape Bird is from the Erebus track. However, in a coincidence that demonstrated just how much the crew had going against them that day, the Cape Bernacchi cliffs are approximately three times larger than those of Cape Bird, meaning that they would appear from the flight deck to be much the same - certainly Peter Mulgrew never seemed to notice, so what chance did Captain Collins have?
Much seems to be made of Captain Vette's motivation to clear his friend's name, but he himself says that was only a minor part of it - what bothered him was that as far as he was concerned Captain Collins was probably the most cautious and conscientious pilot he knew, and he reasoned that whatever had happened in Antarctica to allow Jim Collins to fly into a mountain, given the kind of pilot Collins was - Vette didn't think much of anyone's chances, including his own, if faced with that kind of situation.