AVIATION experts in India yesterday sifted through wreckage from the world's worst mid air collision in which 350 people died on Tuesday.
Last night, nearly 300 of the bodies had been recovered, but investigators said their inquiry would be lengthy.
Wreckage was strewn over 4 sq miles after a Saudi Arabian Airlines Boeing 747, which had just taken off from New Delhi's international airport, collided with an incoming Russian built Kazakh airways Ilyushin 76 cargo plane, 50 miles south west of the airport on Tuesday evening.
Meanwhile, accident investigators seized all radar data and tapes containing the final conversation between air traffic control and the two pilots.
Data from a flight beacon in neighbouring Rajasthan state, located in the direct flight path of all incoming and outgoing aircraft from Delhi had also been handed over to them.
The federal civil aviation secretary, Mr Yogesh Chandra, said preliminary findings from the flight recorders of both aircraft seemed to indicate human error as the cause of the accident.
He told newsmen in Delhi yesterday the two aircraft had not collided head on, as the Ilyushin's cockpit and fuselage were found intact and the bodies of its 38 passengers and crew were not charred. The Saudi aircraft, however, suffered greater damage as it carried a larger quantity of fuel.
The cockpit voice recorder of the llyushin had also been recovered, but the one from the Saudi jet was still missing.
Mr Chandra, however, admitted that for the time being it was difficult to say what actually happened.
Meanwhile, speculation as to the cause ranged from inadequate and obsolete radar equipment at Delhi's international airport to a possible misunderstanding by one of the pilots because of language problems.
Pilots and the Air Traffic Controllers Guild said the refusal by the military to give adequate space for civil flights for unexplained "security reasons" might also have contributed to the accident.
Federal aviation officials said 10 "near" crashes over the past year due to communication problems had led to India's directorate of civil aviation recently calling a meeting of foreign airlines mostly from the former Soviet republics, to take corrective measures.
During the domestic Indian airlines strike three years ago, the pilot of an Uzbek Airways aircraft taken on lease was unable to understand instructions and landed at a military air base instead of the civilian one.
Another Uzbek pilot landed at Bombay's smaller Juhu flying club airfield instead of the international Sahar airport, while a third crash landed at Delhi. Fortunately, there no casualties in any of these mishaps.
Aviation officials, meanwhile, said the control tower at Delhi's airport had "obsolete equipment" such as primary radars capable only of determining the distance of the aircraft, but incapable of knowing whether descending or ascending aircraft were maintaining the height they had been assigned.
However, senior officials said the landing facility equipment currently under use was category II, which was being upgraded to category III by March with help from an American manufacturer.
