Change of a flight plan waypoint and the Antarctic whiteout phenomenon have been generally blamed for causing the DC10 pilot to think that he was somewhere other than where he was actually located. There is no place in airliner navigation for a pilot to think he is somewhere; he must know, with no uncertainty, where his aircraft is located and where it is heading.
Change of flight plan waypoint and whiteout became relevant to the accident only when Captain Collins descended his aircraft to very low altitude, using an unorthodox descent procedure, contrary to his briefing and training.
Aircrew scheduled to operate Antarctic flights were given training in an approved descent procedure for use when the McMurdo area might be obscured by cloud. Captain Collins and his co-pilot First Officer Cassin received this training, and had they followed this procedure there would have been no accident.
Regrettably, Captain Collins did not descend according to his training. He descended visually using a circling procedure in an apparent attempt to maintain clear air below the cloud mass obscuring Mt Erebus.
Approaching McMurdo Captain Collins descended his aircraft in circles from the safety altitude of 16,000 feet to 10,000 feet and then to 6000 feet. He then fatally descended further, heading south, to 2000 feet, and because of a lowering cloud base, descended even further until impact with the lower slopes of Mt Erebus at 1500 feet.
In deciding to avoid terrain by visual means it is vital that a pilot is able to see the terrain he seeks to avoid. Captain Collins did not see Mt Erebus because it was obscured by the cloud he was attempting to descend beneath.
Numerous indications were available to Captain Collins that he was heading for Mt Erebus at extremely low altitude. His co-pilot was unable to raise McMurdo on VHF radio. The crew never received positive radio signals from the Tacan navigation aid.
Crucially, Captain Collins was offered, and accepted, a radar-guided descent from the safety height of 16,000 feet. However, radar contact with McMurdo was never established because Captain Collins instead descended to low altitude using a procedure of his own devising north of Mt Erebus. This ensured that radar contact with McMurdo could not be established. He fatally continued descending, without radar guidance, until colliding with the snow-covered slopes of Mt Erebus at 1500 feet.
The failures of reception of radio communications, navigation aids and radar contact did not alert Captain Collins to the presence of Mt Erebus ahead. Instead he navigated his aircraft into the mountain.
A military Starlifter aircraft following 40 minutes behind the DC10 was also offered a radar-guided descent and maintained the safety height of 16,000 feet until radar contact with McMurdo was established before descending further. The Starlifter made a safe, radar-guided descent to McMurdo. Had Captain Collins not discarded the radar guidance offered to him in favour of his own unorthodox descent procedure, there would have been no accident.
The weather at McMurdo was below the company limits for the approved cloud-break procedure. Captain Collins' alternate sightseeing area was at the south magnetic pole. An earlier Air New Zealand flight, faced with similar weather conditions, had flown to this alternate and returned safely to New Zealand. Captain Collins departed from approved procedures in an attempt to show his passengers the McMurdo and Scott base areas, with tragic outcome.
We all have absolute sympathy for the relatives of those tragically killed in the Erebus accident. There is no similar sympathy on the part of Peter Dunne and Paul Holmes for those Air New Zealand personnel, and their families, unfairly and incorrectly blamed by the late Peter Mahon for the DC10 accident on Mt Erebus. Peter Mahon's allegation that they had lied under oath when giving evidence was successfully appealed by Judicial Review to the New Zealand Court of Appeal. This caused the resignation of Peter Mahon as a judge. His subsequent appeal to the Privy Council supported the finding of the New Zealand Court of Appeal.
Peter Dunne's call for exoneration of the DC10 crew involved in the Mt Erebus accident relies on Paul Holmes' recent book, Daughters of Erebus. In the prologue to this book, Holmes writes: "I have not consulted some who for 30 years have held Mahon to be wrong and have called for the pilots to shoulder at least some of the blame for the Erebus disaster." Holmes consulted only those persons he knew would agree with his preconceived intention to exonerate Captain Collins. His book is an extremely biased account of responsibility for the Erebus accident. To base an appeal for exoneration of the pilots on this book is grossly mistaken.
Responsibility for the Erebus tragedy must remain with Captain Collins, as found by the official accident investigation. This finding is still valid.
Captain Derek Ellis is a former British Airways B747 and Concorde pilot who now lives in Kerikeri.
