A sudden, unexplained lurch on the controls by the co-pilot sent a Russian Tu-154 airliner spinning to the ground, killing 145 passengers and crew last week, according to the findings of an investigating committee made public on Tuesday.
The head of the committee, Deputy Prime Minister Ilya Klebanov, ruled out a fault with the aircraft as the cause of the crash, Russia's worst air disaster for decades, near Irkutsk in eastern Siberia.
Instead, co-pilot Sergei Didenko, a 40-year-old father of two daughters who was at the controls in the fateful final seconds of the flight was singled out for responsibility.
Investigators said they were still trying to establish why such an experienced pilot, with 2,004 hours flying time on the Tu-154, should make such a deadly mistake.
According to Klebanov, the black box flight data recorders showed no problems with the "emotional state" of Didenko and the captain, 51-year-old Valentin Goncharuk, and both were well rested before the flight.
The only hint of anything untoward was that the co-pilot's reactions to the captain's instructions had not always been "adequate" during the flight, said Klebanov.
"We must try to understand why on a plane in full working order in fine weather conditions, at a certain moment the pilots took the wrong actions. For us that is question number one," Klebanov told a press conference in Moscow.
The last time pilot error was blamed for a major Russian air disaster was in 1994, when an Aeroflot Airbus A-310 crashed in western Siberia after the pilot left his 15-year-old son at the controls.
Pilots Goncharuk and Didenko, along with five other members of the crew, were being buried on Tuesday in a single grave in the town of Artyom, near Vladivostok on Russia's Pacific coast, where most of them lived.
Drawing on the committee's report and other sources, an approximate picture of the last few moments of the Tu-154 can be pieced together.
Shortly before 2:10 a.m local time on July 3 the Tu-154, flying from Yekaterinburg in the Urals to Vladivostok, prepared to land at Irkutsk to refuel.
According to the official report, the autopilot was switched off and Didenko was at the controls, under the close supervision of Goncharuk.
The aircraft was 800 metres (2,800 feet) above the ground, about to make its fourth and final turn to bring it into line with the runway at Irkutsk, when something went badly wrong.
In Klebanov's words, the aircraft went out of control, "due to the unintentional transfer of the aircraft, with a nearly complete rotation of the controls, to a wide angle of attack."
This in turn "led to the aircraft stalling and going into a spin with a resulting collision with the ground," he said.
That could either mean that Didenko suddenly pulled back the controls as far as they would go, forcing the aircraft's nose up and making it stall, or he banked it too sharply to one side.
It took 11 seconds from the moment Didenko made the mistake to send the aircraft into a "corkscrew" spin, according to Rudolf Teimuzarov, an aviation expert and member of the investigating committee.
Twenty-two seconds after that, the Tu-154 hit the ground near the village of Burdakovka, killing everyone on board and scattering debris over a 500 metre (yard) radius.
"When it went into a spin, it was virtually impossible to correct the situation. Not even a test pilot could have done that," said Teimuzarov.
Klebanov ruled out any other explanations for the crash, including faults with the 15-year-old aircraft, bad weather or mistakes by controllers on the ground.
"After analysing the black boxes... the committee of inquiry ... concluded that the engines and the controls had functioned normally," he said.
The preliminary report into the disaster was finalised on Monday and presented to President Vladimir Putin, but the committee waited until Tuesday before making it public.
The Irkutsk crash was the worst air disaster in Russia since the Soviet Union collapsed in 1991. Putin declared Thursday a national day of mourning.
The accident was also the third fatal crash involving aircraft either flying in or out of Irkutsk in the space of just seven years.
After a spate of air crashes in the 1990s, Russia increased government oversight of the aviation industry and safety standards have improved significantly, according to western experts -- MOSCOW (AFP)
© 2001 Al Bawaba (www.albawaba.com)
