The causes attributed to the Mt Erebus Crash were -and still are- highly controversial.
The causes attributed to the Mt Erebus Crash were -and still are- highly controversial.
When Air New Zealand flight 901 was confirmed to be missing, immediate speculation was that mechanical faults were to blame. There were a number of cases with other DC-10 planes where there were mechanical faults that lead to the plane’s eventual crash. This was quickly ruled out as the plane’s engines and body were up to standard.
It was soon discovered that a change in flight plans could have been responsible for the crash. Nineteen days prior (November 9th 1979) to the planned take-off for Flight 901, pilots Captain Jim Collins and First Officer Greg Cassin attended a ‘route qualification briefing’. This was to inform them of rules and regulations surrounding minimum and recommended altitudes that they could fly at. Also given, were printouts of the flight route that the DC-10 would be flying. According to this flight plan, the plane would fly over the McMurdo Sound which is a flat section of sea ice.
On the 28th of November, the departure date for the sightseeing flight, a ‘navigational co-ordinate’ was changed. The airline believed that it was just a small change, nothing that would drastically alter the flight plan. However, there had been a typing error in the plans months earlier. This caused the route to move east by approximately 27 nautical miles, meaning that flight 901 wouldn’t be flying over the McMurdo Sound but rather over Mt Erebus. This information was unknown by the pilots and crew.
According to black box recordings, and information gathered from the wreckage, Collins had been given permission by Mac Centre to descend. Collins had briefed his flight crew on his plan to descend. At 1500 ft, the ground proximity warning system (GPWS) started to sound, warning the crew that they were too low. Just over 4 hours into the journey, at 12.49pm, the DC-10 crashed into the lower slopes of Mt Erebus.
Once site investigations were carried out and the bodies of the 257 passengers returned to New Zealand, Ron Chippindale, who was appointed ‘Chief Investigator’, began his report on the Erebus Crash. His “Official Accident Report” is regarded as the official summary of the crash. However, when released, it’s sparked much controversy among New Zealanders. This led to Hon. Justice Peter Mahon publishing the ‘Royal Commission of Inquiry’. Both reports attributed different factors to the cause of the crash, but disagreed as to which was the main cause.
When Air New Zealand flight 901 was confirmed to be missing, immediate speculation was that mechanical faults were to blame. There were a number of cases with other DC-10 planes where there were mechanical faults that lead to the plane’s eventual crash. This was quickly ruled out as the plane’s engines and body were up to standard.
It was soon discovered that a change in flight plans could have been responsible for the crash. Nineteen days prior (November 9th 1979) to the planned take-off for Flight 901, pilots Captain Jim Collins and First Officer Greg Cassin attended a ‘route qualification briefing’. This was to inform them of rules and regulations surrounding minimum and recommended altitudes that they could fly at. Also given, were printouts of the flight route that the DC-10 would be flying. According to this flight plan, the plane would fly over the McMurdo Sound which is a flat section of sea ice.
On the 28th of November, the departure date for the sightseeing flight, a ‘navigational co-ordinate’ was changed. The airline believed that it was just a small change, nothing that would drastically alter the flight plan. However, there had been a typing error in the plans months earlier. This caused the route to move east by approximately 27 nautical miles, meaning that flight 901 wouldn’t be flying over the McMurdo Sound but rather over Mt Erebus. This information was unknown by the pilots and crew.
According to black box recordings, and information gathered from the wreckage, Collins had been given permission by Mac Centre to descend. Collins had briefed his flight crew on his plan to descend. At 1500 ft, the ground proximity warning system (GPWS) started to sound, warning the crew that they were too low. Just over 4 hours into the journey, at 12.49pm, the DC-10 crashed into the lower slopes of Mt Erebus.
Once site investigations were carried out and the bodies of the 257 passengers returned to New Zealand, Ron Chippindale, who was appointed ‘Chief Investigator’, began his report on the Erebus Crash. His “Official Accident Report” is regarded as the official summary of the crash. However, when released, it’s sparked much controversy among New Zealanders. This led to Hon. Justice Peter Mahon publishing the ‘Royal Commission of Inquiry’. Both reports attributed different factors to the cause of the crash, but disagreed as to which was the main cause.
Chippindale's "Official Accident Report"
When Chippindale’s controversial report was released, the conclusions shocked the country. After initial investigations were carried out, Chippindale published his “Official Accident Report” in June1980. This report attributed the cause of the crash to ‘pilot’s error’. Chippindale was a member of the first site investigation team that arrived in Antarctica on the 29th of June. When the site investigation was over, Chippindale continued his enquiry, even travelling overseas to examine to black box recordings, and talk to those who were examining the scripts. While in New Zealand, he analysed the weather conditions the day of the crash, as well as how the flight crew acted and responded before and during the crash. He concluded that, among other factors, had Captain Collins stayed above the 6000 ft recommended altitude (VMC), he would have been flying in a cloud free area and thus, the plane would not have crashed. Chippindale also placed blame with Air New Zealand and the Civil Aviation Division, saying that Air New Zealand had failed to “notify the crew of the change to their flight plan from that on which they had been briefed,” However, the report continued to say that this was not an error that led to the crash. While Chippindale did agree that the white-out conditions at the time did result in an “an area of limited visibility” for the pilots, he didn’t think that it was a major cause of the crash. |
The Mahon Report
Mahon concluded that the crash of flight 901, contrary to Chippindale’s report, was not caused by pilot error. Sydney lawyers, W.D. Baragwanath and G.M. Harrison, who were assisting Mahon in his investigations, ruled out pilot error but said that “navigational error by flight operations” were the cause of the fatal crash. Mahon’s entire investigation then took on this theory. His report said that the crash had been caused by “10 factors; [which] the disaster would not have occurred had any one of them not been present”. However, Mahon did go on to say that one dominant cause of the disaster was the mistake made by Air New Zealand staff who mapped the flight path, and, in Mahon’s words, “programmed the aircraft to fly directly at Mt Erebus and omitted to tell the aircrew”. The ‘Mahon Report’, as the inquiry soon came to be known as, also attributed the ‘whiteout’ phenomenon to be a cause of the cash. Before writing the report, Mahon researched the phenomenon, among other things, in order to make sure that he fully understood the conditions that the plane had encountered. His report stated that a “malevolent trick of polar light” meant that the crew wouldn’t have been able to see the mountain appearing in the path of the plane. Mahon further stated that “sector whiteout” phenomenon made it appear that the horizon was flat, and so mislead the crew even more. |
Due to the location of the crash, and its severity, there were no eye witness reports that could be used to confirm/solve the exact cause of the crash. However, with the help of data from the plane's recorders and instruments, camera's that belonged to the passenger's on board, the plane's black box, and the respective reports of Ron Chippindale, and Hon. Justice Peter Mahon, a fair picture of the Flight 901's last moments can be formed.