DC10 crash blamed on omissions by airline

Press, 28 April 1981, Page 3

DC10 crash blamed on omissions by airline

Wellington reporter

Pilot error is rejected as a cause of the Erebus crash in the report of the Royal Commission of inquiry into the disaster. The command pilot. Captain T. J. Collins, his first officer. First Officer G. M. Cassiri, and the crew of the DCIO are exonerated from any fault. The Royal Commission’s report differs from that of the Chief Inspector of Air Accidents. Mr R. Chippindale. in this respect. The Royal Commission found that the crew properly relied on the accuracy of the inertial navigation system and believed they were on a track which took them down the middle of McMurdo Sound.

On the question of the pilot taking the aircraft down to a height of 1500 feet, the Royal

Commission (Mr Justice Mahon) found that the flight had been authorised by AitTraffic Control at McMurdo to descend to that level and

that the crew acted properly in doing so. The Royal Commission found that the minimum

“safe altitudes” prescribed for Antarctic flights — suggested by Air New Zealand and approved by the Civil Aviation Division of the Ministry of Transport — were misconceived.

These altitudes —16,000 ft with descent to 6000 ft south of Ross Island — had no

relation to the realities of sightseeing flights or to genuine safety requirements, the Royal Commission said. In practice, Air New Zealand and the pilots disreganded these altitudes and, in the Royal Commission’s opinion were justified in doing so. “As it happens, flights as low as 1500 ft are perfectly ■safe in clear weather and ‘were far in excess of the minimum safe altitudes described by the regulations. They were considered safe and'acceptable by the United States Navy and there is no doubt at all that no question of breach of any safety rules : arose in respect of flights at (this level,” the report says. | Flight captains were es- ' pecially briefed to descend if

they wished into the McMurdo area on any flight level authorised and approved by the United Stales air traffic controller there, the report says.

The Royal Commission emphasises in its report that it was not concerned with legal responsibility, but was required by the terms of reference to identify any culpable ayt or omission that was a cause or a contributing cause of the disaster. For that purpose, it took into account 10 factors preceding the crash: • Captain Collins had complete reliance on the accuracy of the navigation system of his aircraft.

• Captain Collins was not supplied, either in the prior briefing or on the morning of the flight, any topographical map on which had neen drawn the track along which the computer system would navigate the aircraft. • Captain Collins plotted that navigation track on the night before the flight on a ;■ map or maps and on his own £ atlas *

• The direction of the last leg of the flight path to be programmed into the aircraft’s computer (from Cape Hallett to McMurdo) was changed on to a collision course with Mount Erebus about six hours before the flight took off. • Neither Captain Collins nor any member of his crew was told of the alteration to the flight track. • Checks in flight at the Balleny Islands and at Cape

Hallett showed that the navigation system was working with its customary extreme accuracy, and that any cross

drift on arrival at their destination would not be greater than about l.tikm, or 3.2 km

at most. • MeMurdo Air Traffic Control believed that the destination point of the aircraft was 43km west of' MeMurdo

Station, and that the aircraft would approach at a low altitude down MeMurdo Sound.

• It was suggested that the aircraft descend to 1500 ft in McMurdo Sound because visibility at that altitude was 64km or more. • Captain Collins accepted this suggestion and decided

to descend to that altitude. • The nature of the c|oud base in Lewis Bay (on the

aircraft's actual flight path) and the unrelieved whiteness of the snow-covered terrain beneath the overcast combined to produce a visual illusion known as “whiteout.” This prevented the crew from seeing the mountain in their path. The Royal Commission finds that if any one of these 10 factors had not existed there would have been no disaster. “It therefore required the coincidental existence of no less than 10 factual circumstances to make the disaster possible at all. The collision of the aircraft with the mountain slopes was a million to one chance,” the report says. Of the contributing causes listed by the Royal Commis-

sion only two — the second and the fifth — were held to be created by blameworthy acts or omissions. ‘They each result from culpable acts and omissions on the part of the airline and in the case of the second on the part of the Civil Aviation Division also,” the report says. “As a result of forming that opinion as to contributing causes, I am able to reach a decision as to whether or not there was a single cause of the disaster. “In my opinion there was. “The dominant cause of the disaster was the act of the airline in changing the computer track of the aircraft without telling the aircrew. That blend of act and omission acquires its status as the dominant’ cause be-

cause it was the one factor which continued to operate from the time the aircraft

left New Zealand until the time when it struck the slopes of Mount Erebus.” the Royal Commission says. “It is clear that this dom-

inant factor would still not have resulted in disaster had it not been for the coincidental occurrence of the whi-

teout phenomenon. “But the conditions of visual illusion existing in Lewis Bay would have no effect on flight TE9OI had the navigation track of the aircraft not been changed,

for it was only the alteration to the navigation track which brought the aircraft into

Lewis Bay instead of McMurdo Sound. “In my opinion, therefore, the single dominant and effective cause of the disaster was the mistake made by those airline officials who programmed the aircraft to fly directly at Mount Erebus and omitted to tell the aircrew. "That mistake is directly attributable, not so much to the persons who made it, but to the incompetent administrative airline procedures which made the mistake possible,” the report says. “In my opinion, neither Captain Collins nor First Officer Cassin nor the flight engineers made any error which contributed to the disaster, and were not responsible for its occurrence.”