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There are many theories but still nothing definitive about what brought down a Russian airliner in Egypt over the weekend. All 224 people aboard were killed when the plane crashed in the Sinai Peninsula on Saturday. The airline insists there was no human error or mechanical problem. Safety regulators say it's too soon to draw conclusions. These responses come as forensics experts in Russia begin to identify victims, as NPR's Corey Flintoff reports from Moscow.
COREY FLINTOFF, BYLINE: At St. Petersburg's Pulkovo Airport, mourners created memorials to the victims of the crash, piling up flowers and toys. A government plane brought 140 bodies from the crash site in Egypt with another flight scheduled for this evening. Meanwhile, Metrojet, the company that owned the downed Airbus A321, held a news conference in Moscow. This is Alexander Smirnov, a Metrojet executive.
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ALEXANDER SMIRNOV: (Speaking Russian).
FLINTOFF: Smirnov says the company is ruling out a technical fault in the aircraft or pilot error. Metrojet executives said that despite earlier reports, the crew had not complained of mechanical problems with the plane and had not called air-traffic controllers in Cairo to request an emergency landing. They suggest that there must've been some external factor in the crash. Metrojet's speculations drew a quick response from Alexander Neradko of Russia's air safety watchdog.
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ALEXANDER NERADKO: (Speaking Russian).
FLINTOFF: He said the company's statement was premature and not based on facts. Neradko said that there's still a lot of work to be done examining the wreckage and reviewing information from the plane's flight data recorders. More details have emerged about the airline, which was said to be having financial problems, and the aircraft, which had been in a significant accident in 2001 that caused severe damage to its tail section. Metrojet's technical chief, Andrei Averyanov, said that was fully repaired.
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ANDREI AVERYANOV: (Speaking Russian).
FLINTOFF: He said the plane was rebuilt by Airbus and that it's been thoroughly checked every two years since then. Yuri Sytnik is an aviation analyst in Moscow who's looked at the changes in the altitude of the plane just before it fell. He says it shows the plane dropping then briefly regaining altitude.
YURI SYTNIK: (Through interpreter) This is not an explosion. Most likely, it was the mechanical destruction of the plane, and the crew, not understanding what was going on, tried to cope with it. When the tail fell off, they lost control and didn't have time to contact anyone.
FLINTOFF: One big concern hovering over the investigation is whether it could have been an act of terrorism. On Saturday, an Egyptian rebel group affiliated with the Islamic State claimed that it had downed the plane as revenge for hundreds of Muslims killed by Russian airstrikes in Syria. Egyptian and Russian officials quickly dismissed that claim, saying the rebels didn't have the weapons necessary to shoot down an aircraft flying at more than 30,000 feet. One remaining possibility is that the plane was destroyed by a bomb that was somehow smuggled aboard. Analysts say that's a question that should be fairly quickly resolved by tests for explosive residues. Corey Flintoff, NPR News, Moscow. Transcript provided by NPR, Copyright NPR.