The plane's "black boxes" were sent to Moscow, where experts will try to remove noise from the recorders in order to find out why the plane went down, investigators said.
The Tu-154 jet belonging to the Vladivostokavia airline crashed Tuesday while trying to land at Irkutsk, a Siberian city about 2,600 miles east of Moscow.
The state commission investigating the crash will have preliminary information about the cause by Monday, Deputy Prime Minister Ilya Klebanov told the Interfax news agency.
He said local aviation experts had recovered information from two of the aircraft's three flight recorders, but the analysis was incomplete. Noise from the recordings can be removed only with equipment available in Moscow, Klebanov said.
Investigators on Thursday ruled out terrorism or an onboard fire as the cause of the crash, the ITAR-Tass news agency said. Nikolai Geniyevsky, the regional transportation ministry's senior official, said the plane fell vertically with a small right-side roll and caught fire after it hit the ground.
About 170 relatives of crash victims have arrived in Irkutsk, ITAR-Tass said. They were put up in hotels, where medical aid and psychological counseling were available.
Klebanov, head of the investigating commission, and Emergency Situations Minister Sergei Shoigu met with the relatives, ITAR-Tass said.
The aircraft was flying at a height of 2,800 feet when it made a sudden 180-degree turn and plunged into a meadow surrounded by forest about 20 miles outside Irkutsk, officials said.
The ground controllers' last radio contact with the plane was four minutes before the crash, regional air transport official Yuri Zhuralev said.
The weather was clear and the plane was "in a normal technical readiness" when it took off, Klebanov was quoted as saying by NTV television. It had almost reached the airport and the runway was visible to the pilots, he said.
The 15-year-old plane was leased by the airline from China last year and had been overhauled two months ago at Moscow's Vnukovo Airport hangars, ITAR-Tass said Wednesday.
It was carrying 136 passengers six of them children and nine crew members. Twelve of the passengers were Chinese citizens, the Chinese Foreign Ministry confirmed Thursday.
The plane was en route from Yekaterinburg in the Ural Mountains to Vladivostok, the major port on Russia's Pacific Coast. It was to land in Irkutsk for refueling and passenger discharge.
Following the collapse of the Soviet Union, civil aviation fell into a steep decline as hundreds of small airlines were spun off from the one-time monolithic Aeroflot. Russia and other former Soviet republics were plagued with air crashes as aircraft mainenance and supervision deteriorated. But in recent years, the number of crashes lessened.
The three-engine Tupolev-154, first put into commercial service in 1972, is the workhorse of Russia's domestic airlines and is widely used throughout the former Soviet Union and Eastern Europe, as well as in China.
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