No Terrorist Link Found in Twin Russian Plane Crashes

Investigators combing the wreckage of two Russian airliners that crashed within minutes of each other have found no evidence of terrorism and various explanations are being studied for the twin tragedies, officials said Wednesday.

“We are considering several possibilities, including a terrorist act, a technical malfunction and human error. At this stage we do not rule out any of these possibilities,” Russian Prosecutor General Vladimir Ustinov told President Vladimir V. Putin. The two plane crashes Tuesday night claimed the lives of all 89 people on board.

Putin appointed a state commission to investigate the incidents. “I rely on you to make sure that your first steps will be to seek and provide absolutely full, objective and accurate information about what happened,” Putin said during the televised meeting with Ustinov and other officials including the commission head, Transportation Minister Igor Y. Levitin.

A spokesman for the Federal Security Service, or FSB, the main successor to the Soviet-era KGB, said human error appeared to be a more likely explanation for the crashes.

Putin ordered preparation of legislation to transfer security control at airports, including preflight checks, from the airports to the Interior Ministry. He also declared today a day of mourning.

One plane, a Tu-134 operated by Volga-Aviaexpress, a small regional company, crashed in the Tula region south of Moscow on its way from the capital’s Domodedovo Airport en route to Volgograd, killing all 43 passengers and crew members on board, authorities said. The crash scene, said a rescuer quoted by the Russian news agency Itar-Tass, was “a very depressing sight” with parts of the plane, fragments of bodies and passengers’ belongings scattered in a radius of more than half a mile.

The second jet, a Tu-154 operated by Sibir Airlines, a major Russian carrier, took off from the same airport and was headed to the Black Sea resort of Sochi when it crashed near the southern city of Rostov-on-Don, killing all 46 on board.

Ilya Novokhatsky, a Sibir spokesman, said the debris from that crash was spread over a mile-wide area “and that can potentially indicate an explosion on board.” Both planes crashed about 11 p.m. Tuesday, the Tu-134 about 30 minutes into its flight and the Tu-154 about 1 1/2 hours into its journey.

The crashes came amid fears that separatist rebels in Russia’s war-torn southern republic of Chechnya would launch attacks before Sunday’s presidential election there. Initial speculation had focused on the possibility that the planes crashed because of terrorist attacks.

Investigators believe that the most probable cause was “a breach of aircraft regulations, which resulted, through carelessness, in the death of passengers,” FSB spokesman Sergei Ignatchenko told Itar-Tass. “As of now, no signs of terrorist attack were found on the sites of crashes of the Tu-134 and Tu-154 planes.”

One explanation being examined for how two planes could have crashed at nearly the same time after taking off from the same Moscow airport was the possibility that there had been some kind of a problem with the jet fuel or the manner in which the planes had been refueled, authorities said.

NTV television reported that there had been an incident of spilled jet fuel on the tarmac near the boarding gates at Domodedovo shortly before the planes departed. That led to a change in departure gates for some flights, causing considerable confusion as passengers sought where to go, it said, speculating that this incident was somehow connected to the crashes.

Domodedovo airport officials, however, stressed that strict security measures were in place and had been properly followed.

The planes that crashed were quite old. The Tu-154 had been in service since 1982, and the Tu-134 since 1977, Russian news agencies said.

Alexander Akimenkov, a test pilot with the State Scientific Research Institute of Civil Aviation, a government agency that certifies aircraft, said that the likelihood of fuel causing a problem was greater in winter, and that he doubted that that was the explanation.

“It is possible that the crew was disabled by an explosion, gas attack or shooting inside the plane’s cockpit,” he said. “It is possible that a small device like a grenade was used for that.”

There were conflicting reports about whether a signal given by the Tu-154 immediately before it disappeared from radar was a general SOS or a hijack alert, but Sibir Airlines spokesman Novokhatsky insisted that it was the latter. “Our pilots used a hidden button, which signals a hijacking threat,” he said.

Aviation officials said the flight data recorders from both planes had been recovered and would be analyzed to help determine the causes of the crashes.

Some Russian politicians said that a coordinated terrorist attack still seemed the most likely explanation for the twin crashes.

“The whole picture of what has happened, including the practically simultaneous fall of both aircraft that flew from the same airport, is a weighty argument in favor of the terrorist attack version,” Gennady Gudkov, a member of the security committee of the lower house of parliament, told Itar-Tass.

Yakov Ryzhak of The Times’ Moscow Bureau contributed to this report.