JOHANNESBURG, South Africa — The Soviet airliner that crashed on South Africa's border with Mozambique two weeks ago, killing President Samora M. Machel of Mozambique and 33 others, was equipped with obsolete instruments that could not alert the crew that they were flying dangerously close to the ground, South Africa said Saturday.
Foreign Minister Roelof F. (Pik) Botha also charged that, according to South Africa's preliminary investigation of the wreckage of the TU-134 twin-engine jet, the crew had apparently ignored other instruments that might have warned them of the danger.
Botha was reacting to suggestions, now widespread in Africa, that his country was responsible for the Oct. 19 crash and that Pretoria's white-led minority government had, in effect, plotted and carried out the assassination of Machel, one of the region's most influential leaders.
No Automatic Warning
The South African foreign minister said the world should realize that the Soviet-manufactured aircraft was not equipped with an automatic ground-proximity warning system that alerts pilots if they descend below a specific altitude. If it had had such instruments, Botha said, the crew might have been able to avoid flying into a hillside.
The five-man crew thought they were about to land at Maputo, Mozambique's capital, when they were actually 45 miles away and over South Africa, Botha added. Certain instruments found in the plane's wreckage about 200 yards inside South Africa had not been activated, Botha said, and there were indications that warnings by other instruments had been ignored by the crew.
"This exposed a serious lack of professionalism," he commented.
The crew members were described by Mozambican and Soviet officials last week as highly experienced aviators with thousands of hours of flight experience each and scores of day and night landings at Maputo airport over the last year and a half.
Alcohol in Blood
Botha alleged as well that alcohol was found in the blood of two of the five Soviet crew members, although it is not certain that they were flying the plane. Medical experts said, however, that the bodies of the four crew members who were killed in the crash may have produced small amounts of alcohol after being left in the hot African sun most of the day.
Dr. Robin Cooper of Britain's Spendlove Biomedical Center in Oxford told Reuters news agency, "If you left a body in a hot country, it would produce its own alcohol." But he added that the level would usually be low.
Although he had quoted a survivor the day after the crash as saying that there had been a loud bang just before impact, Botha on Saturday repeated South African assertions that there was "no evidence of any explosion or abnormal activity at any time while the aircraft was still in the air."
Suspicions of South African involvement stem not only from hostility toward Pretoria from most of its black-ruled neighbors but also from threats made against Mozambique and Machel personally four days earlier by Gen. Magnus Malan, the South African defense minister, who accused the leftist Maputo government of giving African National Congress guerrillas bases from which to attack across the border into South Africa.
"President Machel has chosen the path of terror," Malan declared, "and now experiences the results."
Malan, silent when other South African officials, including President Pieter W. Botha, expressed their grief over Machel's death, said Thursday that those accusing Pretoria of involvement were "going too far" and "playing a dangerous game."
"South Africa was not involved in the crash--in no way," Malan said. "Let this be clear to everyone now. . . . This sort of fanning of suspicion, hate and doubt is to nobody's honor or advantage. It is destructive and even provocative."
South African officials also rebutted accusations that they might have left Machel to die without any medical treatment. A pathologist who took part in the autopsy on Machel in Maputo said his brain injuries were such that he died instantly. One of the 10 survivors had told newsmen in Maputo last week that he and others waited for hours for medical help while South African policemen and intelligence officials searched the plane's wreckage for Mozambican government documents.
A tripartite investigation is under way by South African, Soviet and Mozambican aviation specialists, and American and international experts on air crashes have been invited to participate as well.
But Botha said agreement has not been reached on where the flight recorders, the airplane's "black boxes," will be opened. Soviet specialists say they should be taken to Moscow, where computers are available to analyze their data, but Pretoria is insisting that they not leave South Africa or, at least, not be taken to the Soviet Union.