|Only a huge smudge could be seen at first by the SAR team|
Air New Zealand Flight 901 (TE-901) was a scheduled Air New Zealand Antarctic sightseeing flight that operated between 1977 and 1979. The flight left Auckland Airport in the morning and spent a few hours flying over the Antarctic continent, before returning to Auckland in the evening via Christchurch. On 28 November 1979, the fourteenth flight of TE-901, a McDonnell Douglas DC-10-30 registered ZK-NZP, flew into Mount Erebus on Ross Island, Antarctica, killing all 237 passengers and 20 crew on board. The accident is commonly known as the Mount Erebus disaster.
The initial investigation concluded the accident was caused by pilot error but public outcry led to the establishment of a Royal Commission of Inquiry into the crash. The commission, presided over by Justice Peter Mahon, concluded that the accident was caused by a correction made to the coordinates of the flight path the night before the disaster, coupled with a failure to inform the flight crew of the change, with the result that the aircraft, instead of being directed by computer down McMurdo Sound (as the crew assumed), was re-routed into the path of Mount Erebus. In Justice Mahon's report, he accused Air New Zealand of presenting "an orchestrated litany of lies" and this charge in the end led to changes in senior management at the airline.
The accident is New Zealand's deadliest peacetime disaster. Flight 901, alongside several other related incidents, were highly detrimental to the reputation of McDonnell Douglas DC-10 aircraft within the public. Following the crash, DC-10 aircraft in New Zealand were replaced by Boeing 747s.
Flight and aircraft
|Air New Zealand's sightseeing brochure|
The flight was designed and marketed as a unique sightseeing experience, carrying an experienced Antarctic guide who pointed out scenic features and landmarks using the aircraft public-address system, while passengers enjoyed a low-flying sweep of McMurdo Sound. The flights left and returned to New Zealand the same day.
Flight 901 would leave Auckland International Airport at 8:00 am for Antarctica, and arrive back at Christchurch International Airport at 7:00 pm after flying a total of 5,360 miles (8,630 km). The aircraft would make a 45-minute stop at Christchurch for refuelling and crew change, before flying the remaining 464 miles (747 km) to Auckland, arriving at 9:00 pm. Tickets for the November 1979 flights cost NZ$359 per person (equal to about NZ$1,386 in the first quarter of 2013).
Dignitaries including Sir Edmund Hillary had acted as guides on previous flights. Hillary was scheduled to act as the guide for the fatal flight of 28 November 1979, but had to cancel owing to other commitments. His long-time friend and climbing companion, Peter Mulgrew, stood in as guide.
The flights usually operated at about 85% of capacity; the empty seats, usually the centre ones, allowed passengers to move more easily about the cabin to look out of the windows.
The aircraft used on the Antarctic flights were Air New Zealand's eight McDonnell Douglas DC-10-30 trijets. The aircraft on 28 November was registered ZK-NZP. The 182nd DC-10 to be built, and the fourth DC-10 to be introduced by Air New Zealand, ZK-NZP was handed over to the airline on 12 December 1974 at McDonnell Douglas's Long Beach plant. It was the first Air New Zealand DC-10 to be fitted with General Electric CF6-50C engines as built, and had logged 20,750 flight hours prior to the crash.
(All times are as at McMurdo Base: New Zealand Standard Time; UTC+12. Mainland New Zealand was running on New Zealand Daylight Time (UTC+13) at the time of the crash.)
Circumstances surrounding the accident
Captain Jim Collins and co-pilot Greg Cassin had never flown to Antarctica before, but they were experienced pilots and were considered qualified for the flight. On 9 November 1979, 19 days before departure, the two pilots had attended a briefing in which they were given a copy of the previous flight's flight plan.
|Expected and actual track of the flight|
Unknown to Captain Collins at the time of the briefing, the flight plan coordinates transcribed into Air New Zealand's ground computer differed from the route flight plan approved in 1977 by the New Zealand Department of Transport Civil Aviation Division. The approved flight plan was along a track directly from Cape Hallett to the McMurdo non-directional beacon (NDB), which, coincidentally, entailed flying almost directly over the 12,448-feet peak of Mount Erebus. However, the printout from Air New Zealand's ground computer system presented at a briefing on 9 November corresponded to a southerly flight path down the middle of the wide McMurdo Sound, leaving Mount Erebus approximately 27 miles to the east. The majority of previous flights had also entered this flight plan's coordinates into their aircraft INS navigational systems and flown the McMurdo Sound route, unaware that the route flown did not correspond with the approved route.
Captain Leslie Simpson, the pilot of a previous flight on 14 November, and also present at 9 November briefing, compared the coordinates of the McMurdo TACAN navigation beacon (approximately three miles east of McMurdo NDB), and the McMurdo waypoint that the flight crew had entered into the INS, and was surprised to find a large distance between the two. After this flight, Captain Simpson advised Air New Zealand's Navigation section of the difference in positions. For reasons that were disputed, this triggered Air New Zealand's Navigation section to subsequently resolve to update the McMurdo waypoint coordinates stored in the ground computer to correspond with the coordinates of the McMurdo TACAN beacon, despite this also not corresponding with the approved route.
The Navigation section changed the McMurdo waypoint co-ordinate stored in the ground computer system at approximately 1:40 am on the morning of the flight. Crucially, the flight crew of Flight 901 was not notified of the change. The flight plan printout given to the crew on the morning of the flight, which was subsequently entered by the flight crew into the aircraft's INS, differed from the flight plan presented at 9 November briefing and from Captain Collins' map mark-ups which he had prepared the night previously. The key difference between the routes was that the flight plan presented at 9 November briefing corresponded to a track down McMurdo Sound, giving Mount Erebus a wide berth to the east, whereas the flight plan printed on the morning of the flight corresponded to a track that coincided with Mount Erebus. In contrast to the McMurdo Sound route, the updated route would result in a collision with Mount Erebus if this leg was flown at an altitude of less than 13,000 feet (4,000 m). Additionally, the computer program was altered such that the standard telex forwarded to Air Traffic Controllers at McMurdo displayed the word "McMurdo" rather than the coordinates of latitude and longitude, for the final waypoint. During the subsequent inquiry Justice Mahon concluded that this was a deliberate attempt to conceal from the United States authorities that the flight plan had been changed, and probably because it was known that the United States Air Traffic Control would lodge an objection to the new flight path.
The flight had earlier paused during the approach to McMurdo Sound to carry out a descent, via a figure-eight manoeuvre, through a gap in the low cloud base (later estimated to be at approximately 2,000 to 3,000 feet (610 to 910 m)) whilst over water to establish visual contact with surface landmarks and afford the passengers a better view. It was established that the flight crew either was unaware of or ignored the approved route's minimum safe altitude (MSA) of 16,000 feet (4,900 m) for the approach to Mount Erebus, and 6,000 feet (1,800 m) in the sector south of Mount Erebus (and then only when the cloud base was at 7,000 feet (2,100 m) or better). Photographs and news stories from previous flights showed that many of these had also been flown at levels substantially below the route's MSA. In addition, pre-flight briefings for previous flights had authorised descents to any altitude authorised by the US Air Traffic Controller at McMurdo Station. As the US ATC expected Flight 901 to follow the same route as previous flights down McMurdo Sound, and in accordance with the route waypoints previously advised by Air New Zealand to them, the ATC advised Flight 901 that it had a radar that could let them down to 1,500 feet (460 m). The aircraft was not located by the radar equipment, and the crew experienced difficulty establishing VHF communications. The distance measuring equipment (DME) did not lock onto the McMurdo Tactical Air Navigation System (TACAN) for any useful period.
|Wreckage of ZK-NZP|
Changes to the coordinates and departure
The crew input the coordinates into the plane's computer before they departed at 7:21 am from Auckland International Airport (now Auckland Airport). Unknown to them, the coordinates had been modified earlier that morning to correct the error introduced previously and undetected until then. The crew evidently did not check the destination waypoint against a topographical map (as did Captain Simpson on the flight of 14 November) or they would have noticed the change. These new coordinates changed the flight plan to track 27 miles (43 km) east of their understanding. The coordinates programmed the plane to overfly Mount Erebus, a 3,794 m (12,448 ft) high volcano, instead of down McMurdo Sound.
About four hours after a smooth take-off, the flight was 42 miles (68 km) away from McMurdo Station. The radio communications centre there allowed the pilots to descend to 10,000 ft (3,000 m) and to continue "visually." Air safety regulations at the time did not allow flights to descend to lower than 6,000 ft (1,800 m), even in good weather, although Air New Zealand's own travel magazine showed photographs of previous flights clearly operating below 6,000 ft (1,800 m). Collins believed the plane was over open water.
Crash into Mount Erebus
Collins told McMurdo Station that he would be dropping to 2,000 feet (610 m), at which point he switched control of the aircraft to the automated computer system. Outside there was a layer of clouds that blended with the white of the snow-covered volcano, forming a sector whiteout – there was no contrast between the two to warn the pilots. The effect was to deceive everyone on the flight deck, making them believe that the white mountainside was the Ross Ice Shelf, a huge expanse of floating ice derived from the great ice sheets of Antarctica, which was in fact now behind the mountain. As it was little understood, even by experienced polar pilots, Air New Zealand had provided no training for the flight crew on the sector whiteout phenomenon. Consequently, the crew thought they were flying along McMurdo Sound, when they were flying over Lewis Bay in front of Mt. Erebus.
McMurdo Station attempted to contact the flight after the crash and informed Air New Zealand headquarters in Auckland that communication with the aircraft had been lost. United States search and rescue personnel were placed on standby.
Rescue and recovery
Initial search and discovery
At 2:00 pm the United States Navy released a situation report stating:
Air New Zealand Flight 901 has failed to acknowledge radio transmissions. ... One LC-130 fixed-wing aircraft and two UH-1N rotary wing aircraft are preparing to launch for SAR effort.
Data gathered at 3:43 pm was added to the situation report, stating that the visibility was 40 miles (64 km). It also stated that six aircraft had been launched to find the flight.
Flight 901 was supposed to arrive back at Christchurch at 6:05 pm for a stopover including refuelling and a crew change before completing the journey back to Auckland. Around 50 passengers were also supposed to disembark at Christchurch. Airport staff initially told the waiting families that it was usual for the flight to be slightly late but, as time went on, it became clear that something was wrong.
The vertical stabiliser section of the plane, with the koru logo clearly visible, was found in the snow. Bodies and fragments of the aircraft were flown back to Auckland for identification. The remains of 44 of the victims were not individually identified. A funeral was held for them on 22 February 1980.
The recovery effort of Flight 901 was called "Operation Overdue".
Efforts for recovery were extensive, owing in part to the pressure from Japan, as 24 passengers had been Japanese. The operation lasted until 9 December 1979, with up to 60 recovery workers on site at a time. A team of New Zealand Police officers and a Mountain Face Rescue team were dispatched on a No. 40 Squadron C-130 Hercules aircraft.
|One of the most difficult SAR operation ever|
The job of individual identification took many weeks, and was largely done by teams of pathologists, dentists, and police. The mortuary team was led by Inspector Jim Morgan, who collated and edited a report on the recovery operation. Record keeping had to be meticulous because of the number and fragmented state of the human remains that had to be identified to the satisfaction of the coroner. From a purely technical point of view the exercise was both innovative and highly successful, with 83% of the deceased eventually being identified, sometimes from evidence such as a finger capable of yielding a print, or keys in a pocket.
The fact that we all spent about a week camped in polar tents amid the wreckage and dead bodies, maintaining a 24-hour work schedule says it all. We split the men into two shifts (12 hours on and 12 off), and recovered with great effort all the human remains at the site. Many bodies were trapped under tons of fuselage and wings and much physical effort was required to dig them out and extract them.
Initially, there was very little water at the site and we had only one bowl between all of us to wash our hands in before eating. The water was black. In the first days on site we did not wash plates and utensils after eating but handed them on to the next shift because we were unable to wash them. I could not eat my first meal on site because it was a meat stew. Our polar clothing became covered in black human grease (a result of burns on the bodies).
We felt relieved when the first resupply of woollen gloves arrived because ours had become saturated in human grease, however, we needed the finger movement that wool gloves afforded, i.e., writing down the details of what we saw and assigning body and grid numbers to all body parts and labelling them. All bodies and body parts were photographed in situ by U.S. Navy photographers who worked with us. Also, U.S. Navy personnel helped us to lift and pack bodies into body bags which was very exhausting work.
Later, the Skua gulls were eating the bodies in front of us, causing us much mental anguish as well as destroying the chances of identifying the corpses. We tried to shoo them away but to no avail, we then threw flares, also to no avail. Because of this we had to pick up all the bodies/parts that had been bagged and create 11 large piles of human remains around the crash site in order to bury them under snow to keep the birds off. To do this we had to scoop up the top layer of snow over the crash site and bury them, only later to uncover them when the weather cleared and the helos were able to get back on the site. It was immensely exhausting work.
After we had almost completed the mission, we were trapped by bad weather and isolated. At that point, NZPO2 and I allowed the liquor that had survived the crash to be given out and we had a party (macabre, but we had to let off steam). We ran out of cigarettes, a catastrophe that caused all persons, civilians and Police on site, to hand in their personal supplies so we could dish them out equally and spin out the supply we had. As the weather cleared, the helos were able to get back and we then were able to hook the piles of bodies in cargo nets under the helicopters and they were taken to McMurdo. This was doubly exhausting because we also had to wind down the personnel numbers with each helo load and that left the remaining people with more work to do. It was exhausting uncovering the bodies and loading them and dangerous too as debris from the crash site was whipped up by the helo rotors. Risks were taken by all those involved in this work. The civilians from McDonnell Douglas, MOT and U.S. Navy personnel were first to leave and then the Police and DSIR followed. I am proud of my service and those of my colleagues on Mount Erebus.
In 2006 the New Zealand Special Service Medal (Erebus) was instituted to recognise the service of New Zealanders, and citizens of the United States of America and other countries, who were involved in the body recovery, identification, and crash investigation phases of Operation Overdue. On 5 June 2009 the New Zealand government recognised some of the Americans who assisted in Operation Overdue during a ceremony in Washington, D.C. A total of 40 Americans, mostly Navy personnel, are eligible to receive the medal.
|Believed to be the only photo left showing the impact|
Despite Flight 901 crashing in one of the most isolated parts of the world, evidence from the crash site was extensive. Both the cockpit voice recorder and the flight data recorder were in working order and able to be deciphered. Extensive photographic footage from the moments before the crash was available: being a sightseeing flight, most passengers were carrying cameras, from which the majority of the film could be developed.
Official accident report
The accident report compiled by New Zealand's chief inspector of air accidents, Ron Chippindale, was released on 12 June 1980. It cited pilot error as the principal cause of the accident and attributed blame to the decision of Collins to descend below the customary minimum altitude level, and to continue at that altitude when the crew was unsure of the plane's position. The customary minimum altitude prohibited descent below 6,000 ft (1,830 m) even under good weather conditions, but a combination of factors led the captain to believe the plane was over the sea (the middle of McMurdo Sound and few small low islands), and previous flight 901 pilots had regularly flown low over the area to give passengers a better view, as evidenced by photographs in Air New Zealand's own travel magazine and by first-hand accounts of personnel based on the ground at NZ's Scott Base.
|Justice Peter Mahon|
Mahon's report, released on 27 April 1981, cleared the crew of blame for the disaster. Mahon said the single, dominant and effective cause of the crash was Air New Zealand's alteration of the flight plan waypoint coordinates in the ground navigation computer without advising the crew. The new flight plan took the aircraft directly over the mountain, rather than along its flank. Due to whiteout conditions, "a malevolent trick of the polar light", the crew were unable to visually identify the mountain in front of them. Furthermore, they may have experienced a rare meteorological phenomenon called sector whiteout, which creates the visual illusion of a flat horizon far in the distance (it appeared to be a very broad gap between cloud layers allowing a view of the distant Ross Ice Shelf and beyond). Mahon noted that the flight crew, with many thousands of hours of flight time between them, had considerable experience with the extreme accuracy of the aircraft's inertial navigation system. Mahon also found that the radio communications centre at McMurdo Station had authorised Collins to descend to 1,500 ft (450 m), below the minimum safe level.
In para. 377 of his report, Mahon controversially claimed airline executives and senior (management) pilots engaged in a conspiracy to whitewash the inquiry, accusing them of "an orchestrated litany of lies" by covering up evidence and lying to investigators. Mahon found that in the original report Chippindale had a poor grasp of the flying involved in jet airline operation, as he (and the New Zealand CAA in general) was typically involved in investigating simple light aircraft crashes. Chippindale's investigation techniques were revealed as lacking in rigour, which allowed errors and avoidable gaps in knowledge to appear in reports. Consequently Chippindale entirely missed the importance of the flight plan change and the rare meteorological conditions of Antarctica. Had the pilots been informed of the flight plan change, the crash would have been avoided.
On 20 May 1981, Air New Zealand applied to the High Court of New Zealand for judicial review of Mahon's order that it pay more than half the costs of the Mahon Inquiry, and for judicial review of some of the findings of fact Mahon had made in his report. The application was referred to the Court of Appeal, which unanimously set aside the costs order. However, the Court of Appeal, by majority, declined to go any further, and, in particular, declined to set aside Mahon's finding that members of the management of Air New Zealand had conspired to commit perjury before the Inquiry to cover up the errors of the ground staff.
Privy Council appeal
Mahon then appealed to the Privy Council in London against the Court of Appeal's decision. His findings as to the cause of the accident, namely reprogramming of the aircraft's flight plan by the ground crew who then failed to inform the flight crew, had not been challenged before the Court of Appeal, and so were not challenged before the Privy Council. His conclusion that the crash was the result of the aircrew being misdirected as to their flight path, not due to pilot error, therefore remained. But the Privy Council effectively agreed with some of the views of the minority in the Court of Appeal in concluding that Mahon had acted in breach of natural justice in making his finding of a conspiracy by Air New Zealand management. In its judgment, delivered on 20 October 1983, the Privy Council therefore dismissed Mahon's appeal. Aviation researcher John King wrote in his book New Zealand Tragedies, Aviation:
They demolished his case (Mahon's case for a cover-up) item by item, including Exhibit 164 which they said could not "be understood by any experienced pilot to be intended for the purposes of navigation" and went even further, saying there was no clear proof on which to base a finding that a plan of deception, led by the company's chief executive, had ever existed.
"Exhibit 164" was a photocopied diagram of McMurdo Sound showing a southbound flight path passing west of Ross Island and a northbound path passing the island on the east. The diagram did not extend sufficiently far south to show where, how, or even if they joined, and left the two paths disconnected. Evidence had been given to the effect that the diagram had been included in the flight crew's briefing documentation.
Legacy of the disaster
The crash of Flight 901 is one of New Zealand's three deadliest disasters – the others being the Cospatrick disaster in which 470 people died, and the 1931 Hawke's Bay earthquake, which killed 256 people. At the time of the disaster, it was the fourth-deadliest air crash of all time; as of 2014 it ranks 18th. At October 2009, the accident remained New Zealand's deadliest peacetime disaster.
Flight 901, in conjunction with the crash of American Airlines Flight 191 in Chicago six months earlier, severely hurt the reputation of the McDonnell Douglas DC-10. ZK-NZP, along with the other seven Air New Zealand DC-10s, had only just returned to service after being grounded following the crash of Flight 191 when the crash of Flight 901 occurred. Flight 901 was the third deadliest accident involving a DC-10, following Turkish Airlines Flight 981 and American Airlines Flight 191. The event marked the beginning of the end for Air New Zealand's DC-10 fleet, although there had been talk before the accident of replacing the aircraft; DC-10s were replaced by Boeing 747s from mid-1981, and the last Air New Zealand DC-10 flew in December 1982. The occurrence also spelled the end of commercially operated Antarctic sightseeing flights – Air New Zealand cancelled all its Antarctic flights after Flight 901, and Qantas suspended its Antarctic flights in February 1980, only returning on a limited basis again in 1994.
Almost all of the aircraft's wreckage still lies where it came to rest on the slopes of Mount Erebus, under a layer of snow and ice. During warm periods, when snow recedes, it is visible from the air.
A television miniseries, Erebus: The Aftermath, focusing on the investigation and the Royal Commission of Inquiry, was broadcast in New Zealand and Australia in 1988.
The phrase "an orchestrated litany of lies" entered New Zealand popular culture for some years.
Justice Mahon's report was finally tabled in Parliament by the then Minister of Transport, Maurice Williamson, in 1999.
|Cpt Gordon Vette|
In 2008, Justice Mahon was posthumously awarded the Jim Collins Memorial Award by the New Zealand Airline Pilots Association for exceptional contributions to air safety, "in forever changing the general approach used in transport accidents investigations world wide."
In 2009, Air New Zealand's CEO Rob Fyfe apologised to all those affected who did not receive appropriate support and compassion from the company following the incident, and unveiled a commemorative sculpture at its headquarters.
The registration of the crashed aircraft, ZK-NZP, has not been reissued.