Erebus crash: myths and reality
On the 25th anniversary of the Erebus disaster, The Dominion Post sorted out the reality from the myths that surrounded New Zealand's biggest peace-time tragedy.
On November 28, 1979, a wide-bodied DC10 jet operated by Air New Zealand flew into the lower slopes of the world's southernmost active volcano, the 3794-metre-high Mt Erebus in Antarctica, instantly killing everyone on board.
The disaster was at first inexplicable. The crash investigators found that the big jet was operating perfectly. The tape of the cockpit conversations between the pilots revealed nothing untoward till the very final seconds. The hundreds of photos taken by the passengers showed the plane was flying in clear air in good weather.
It was the aviation puzzle of the decade. How could a modern aircraft with the most sophisticated navigation equipment available fly into a towering mountain in broad daylight without anyone aboard seeing what was coming?
The controversy that followed the answers has barely died all these years later.
Chief air accident inspector Ron Chippindale's June 1980 report on the crash blamed the pilots, accusing them of flying too low in flagrant breach of airline orders, while not knowing where they were.
A diagram published with his report, showing the plane apparently flying in aimless circles, helped fuel the perception that TE901 smashed into the mountain while it was hopelessly lost in clouds.
Royal commissioner Justice Peter Mahon, whose report was published almost a year after Mr Chippindale's, stunned the nation by accusing Air New Zealand of a massive cover-up of a computer blunder he said caused the crash.
Exonerating the pilots of all blame, Justice Mahon said the computer navigation track of TE901 had been altered just before the flight, shifting the flightpath from the safe, flat expanse of McMurdo Sound to a collision course with Mt Erebus, without the pilots being told of the change.
Captain Jim Collins, First Officer Greg Cassin and everyone else on the flight deck, including seasoned Antarctic explorer Peter Mulgrew, completely failed to see the looming disaster ahead of them.
Justice Mahon said this failure had two causes. They believed they were over McMurdo Sound, the route of the previous sightseeing flights, the route Captain Collins was told he was going on at the flight briefing a few days before. And they were fooled by the optical illusion known as "whiteout", caused by the sun shining from behind on to snow and ice below and clouds above, making it look as if they were flying over endless flat ice when, in fact, the ground was rising quickly.
In phrases that rang around New Zealand and around the world, Justice Mahon, an eminent judge of the High Court, said Air New Zealand had presented his royal commission with "palpably false evidence" that originated "in a predetermined plan of deception" that could not have been the result of mistakes or faulty memories. "I am forced, reluctantly, to say that I had to listen to an orchestrated litany of lies," he wrote in one of the most thundering denunciations penned in the report.
Political and public pandemonium followed. Morrie Davis, the airline's high-profile chief executive, felt forced to resign. Prime Minister Sir Robert Muldoon, a friend of Mr Davis, savaged Justice Mahon and his report. Pilots and aviation experts took entrenched sides, some supporting the Chippindale report and blaming the pilots, others supporting the Mahon report and blaming the airline.
Air New Zealand went to the Court of Appeal in an attempt to have the Mahon findings overturned. The court stridently criticised the judge, ruling he should not have accused the airline of a cover-up without putting the allegation to its witnesses at the royal commission. Stunned, Justice Mahon resigned.
Justice Mahon, increasingly isolated, appealed to the Privy Council, which, in a damning decision in October 1983, said he had "failed to observe the rules of natural justice" _ about the harshest thing that could be said about a judge.
Air New Zealand declared itself vindicated. The Government and the airline's supporters hailed the Chippindale report as the only true account of the disaster.
Somewhere in all the smoke and fire, myths developed that remain to this day. The many critics of the Mahon report, both pilots and knowledgeable lay people, still say that Captain Collins caused the disaster by ignoring Air New Zealand's "minimum safe altitude" requirement and taking the DC10 down to 1500 feet in mountainous terrain without establishing where he was.
They say that any standing the Mahon report had ended when it was "overturned" by the Court of Appeal and the Privy Council and that Justice Mahon was out of his depth when he conducted the royal commission.
Equally, the many pilot and lay critics of the Chippindale report continue to say that Mahon was right to identify the changed computer coordinates, not notified to the crew, as being the main cause.
DC10 jets were navigated by their computer systems, the Mahon backers say, and Captain Collins was entitled to believe he was flying down the middle of McMurdo Sound, and that he had only descended below the 16,000-foot safety height with the permission of air traffic controllers at the American base at McMurdo.
The Mahon report was not overturned, they say. Only its comments about an "orchestrated litany of lies" were struck out. Its findings on the cause of the crash still stand.
Despite the continuing controversy, the events leading to the disaster are readily verifiable from the Chippindale and Mahon reports, which, in fact, only really differ in their emphasis and on who was to blame.
ANTAS started sightseeing flights to Antarctica in 1977. They proved so popular that Air New Zealand quickly began its own, leaving Auckland in the early mornings to fly to Ross Island, where New Zealand and the United States have permanent scientific bases, Scott Base and McMurdo Base.
The flights did not land on the ice. On reaching the McMurdo Sound area, they would descend to low levels and make slow passes around the island and the bases there, before climbing back to cruising altitude and returning to New Zealand.
At the time, DC10 jets were navigated by computerised inertial navigation systems that were so accurate that the plane could fly for thousands of kilometres on automatic pilot and be lined up with the runway at its destination with little input by the flight crew. (They did not, however, have the amazingly accurate global positioning satellite equipment of today - systems that probably make a repeat of the Erebus crash impossible.)
Before each flight, the crew programmed the computer with the latitude and longitude of a series of "waypoints" along the intended route, the details being supplied by the airline's flight operations division.
The waypoints for the sightseeing flights took the jets down the centre of McMurdo Sound to a point west of the airfield near Scott Base. Most flights before TE901, however, were flown manually in the McMurdo area to give passengers the best views. That meant the pilot disconnected the navigation computer before following the programmed track down the sound.
Early on the morning of November 28, the final waypoint for the Antarctic flights was changed by Air New Zealand's flight operations section from the middle of the sound to a beacon near the airfield. The effect of this change was to shift the flight path 43 kilometres to the east.
In the recriminations that followed, the airline claimed it had merely corrected an "error" and that the McMurdo route itself was a mistake. It said Captain Collins was at fault for disregarding the 16,000-foot safety height, which would have flown it safely over the summit of Mt Erebus.
However, nobody told the crew. It is clear from their comments preserved on the cockpit voice recorder that they believed at all times they were over the sound, not flying toward the mountain.
Peter Mulgrew was heard saying, "Taylor on the right", a reference to the Taylor Valley, which would have been on their right if flying down the sound, and there were references to Mt Erebus being on the left.
Other flights had enjoyed cloudless, sunny days, but, as TE901 approached Ross Island, the area was covered in cloud. Captain Collins asked McMurdo for a radar letdown, then, when he saw a big gap in the clouds, got permission to descend through it under "visual flight rules".
It was the diagram in the Chippindale report of this descent, in two large loops, that conveyed the mistaken impression of flying lost in circles, when the DC10 was in clear air at all times.
Once down to 2000 feet, Collins switched back to the computer track, believing it would take him swiftly down the sound to Scott Base. But, instead, he was flying over Lewis Bay, directly at Mt Erebus, which rose, hidden, into the cloud ceiling above the plane.
Both the Chippindale and Mahon reports said the whiteout effect would make it near-impossible for the crew to see the rising ground ahead, while the Mahon report said that the entrance to Lewis Bay looked like the entrance to McMurdo Sound.
Astonishingly, only one crew member had flown on such a flight before, flight engineer Gordon Brooks. He was the only person to voice any concern. Just 26 seconds before impact, he said: "I don't like this."
Captain Collins immediately decided to fly away. He was heard discussing with First Officer Cassin whether to turn left or right, when, suddenly, the ground proximity warning system shrieked its terrifying alarm: "Whoop- whoop! Pull up!"
But it was too late. Seconds later, TE901 disintegrated as it hit the slope.
THE debate that has raged since has really been over who to blame. Did Captain Collins descend recklessly, without first identifying where the mountains were? Or was the airline at fault for not telling him about the changed computer track?
The 16,000-foot safety ceiling was soon shown to be a smokescreen. Air New Zealand had claimed flights were not allowed lower than that till south of Ross Island, and that they were not allowed lower than 6000 feet at any stage. But a succession of pilots at the royal commission said they had flown as low as 1500 feet in the area with the full knowledge of the airline. They were, after all, sightseeing flights and there was not much to be seen from 6000 feet or 16,000 feet.
Mr Chippindale initially upheld the height restriction claims, but in an interview in 1989, on the 10th anniversary of the disaster, he acknowledged that Air New Zealand had only made the claim to try to avoid insurance liabilities. He accepted that previous flights had also gone down low and that the airline had condoned it.
Mr Chippindale has now retired. This weekend is his golden wedding anniversary, doubtless making the 25th anniversary of the Erebus disaster doubly poignant for him. But he says he does not want to talk about it.
"I try to keep a low profile on it these days," he says. "A lot of people have paid the price for what happened, and it's time everyone moved forward."
Critics have said Justice Mahon would have written a different report if he had had an aviation expert sitting with him. Well, he did have access to one such expert, retired air marshal Sir Rochford Hughes, who was the technical adviser to David Baragwanath, QC, the lawyer assisting the inquiry.
Like many of those who became part of the aftermath, Sir Rochford is now dead, but in 1989 he made it clear he thought Justice Mahon was too lenient on the pilots. "Mahon wrote his report on Erebus entirely on his own, without any reference to either David Baragwanath or certainly myself," Sir Rochford said then. "It was completely contrary to some of the things we had urged him to take cognisance of."
The judge had rightly pinpointed poor organisation inside Air New Zealand for sending flights to Antarctica that were woefully prepared, but he let his sympathy for the dead pilots cloud his views, Sir Rochford said.
"He felt they were fully entitled to rely implicitly on the inertial navigation system which they used on regular routes, but . . . that had its limitations on the Antarctic route and I don't think any of the air force authorities or I would agree that was the way an Antarctic flight should be conducted."
Captain Collins should not have descended without being picked up on radar first or without identifying the high ground, Sir Rochford said. For not doing so, he had to bear his share of the blame with the airline.
Justice Mahon's findings on the cause of the crash were not overturned by the Court of Appeal and the Privy Council. Their decisions relate only to his allegations against the airline of a conspiracy.
In its decision, the Privy Council went out of its way to laud the judge's "brilliant and painstaking investigative work", but said there was no evidence of a conspiracy and Justice Mahon should not have accused it of one without giving it a chance to respond.
Justice Mahon died in August 1986, a folk hero to many New Zealanders who felt he had been treated shabbily by the Muldoon government for exposing the truth about TE901.
Many people, including a group of fellow judges, urged the Labour Government elected in 1984 to knight Peter Mahon, but it did not happen. When he died, there was a clamour of calls, including newspaper editorials, urging a posthumous honour.
Sir Geoffrey Palmer, who was minister of justice and deputy prime minister at the time, seemed particularly disdainful to the idea of knighting Justice Mahon and he remains so to this day.
"Justice Mahon was a very eminent New Zealander and he did a lot of good things, but [the Erebus report] wasn't one of them," Sir Geoffrey said caustically.
Asked why he had opposed granting a knighthood, Sir Geoffey said: "The courts found he had breached natural justice. It's still one of the leading cases about natural justice, it's quoted all the time. Those were difficulties that didn't warrant the hero status people had of him."
In its 1983 decision, the Privy Council expressed the wish that everyone caught up in the Erebus conflagration would move on from it. "The time has now come for all parties to let bygones be bygones so far as the aftermath of the Mt Erebus disaster is concerned. The time for bitter feelings is over."
It was a fond hope then, and probably just as faint all these years later.
The Dominion Post