What Caused Metrojet Flight 9268 to Crash? Theories So Far

Russian air crash memorial
People mourn near a makeshift memorial for victims of the Russian airliner that crashed in Egypt. Various theories are being proposed as possible causes for the crash. Reuters/Peter Kovalev

Latest reports from the ongoing investigations into the downing of the Russian Metrojet Flight 9268 say that "uncharacteristic sounds" were heard moments before the Airbus A321 crashed in Egypt's Sinai Peninsula, killing more than 200 people on board.

There is ongoing debate as to what caused the crash and three main theories have developed so far.

Downed From the Ground

Immediately after the crash, the Islamic State militant group (ISIS) said it had shot down the plane, but Egyptian authorities quickly denied the claims, saying that the group would not have been able to shoot down the liner at an altitude of around 31,000 feet.

Egyptian President Abdel Fattah al-Sisi branded the reports "propaganda," while Russia's Minister of Transport Maxim Sokolov told state news RIA Novosti over the weekend that reports of ISIS shooting down the plane are "unreliable."

However, it seems Russia's position on this theory is more ambivalent. A Kremlin spokesperson said at an official press conference on Monday that it is too early to rule out it, or any other versions of events that led to the crash, before an investigation is complete.

According to the Egyptian military, ISIS affiliates in the region only have shoulder-mounted surface-to-air missiles that are not able to reach even half the distance to the altitude at which the aircraft was flying, CNN reports. On Monday, a source from the group of Airbus specialists who are assisting the Egyptian government with the crash investigation, told Reuters that the plane had not been struck from outside.

Fault On Board

Kogalymavia, the company that owns Metrojet, has dismissed the possibility of either the crew or the mechanics of the plane being at fault. In a press conference held on Monday, airline bosses said that "external mechanical activity," either from within the plane or outside, caused the tragedy. The company also said that a fuel check was carried out on the plane's last refuelling stop and that the aircraft had enough to fly as normal.

The Airbus A321 has been in service since 1994 and had a good safety record. According to the Aircraft Safety Network the jet suffered a tail-strike in 2001, but the airline have said that repairs were made and the last inspection for tail cracks took place in 2013.

However, reports from some British and American news sources have included photographs of the plane, taken between 2012 and 2015, that appear to show a crack at the base of the rudder on the tail.

David Gleave, a U.K.-based aviation safety analyst, told NBC: "The pictures from the Metrojet scene show the very rear of the aircraft, with what's left of the tail fin, a considerable distance from the rest of the wreckage. That would suggest a clean break around the rear pressure bulkhead. I think investigators will be focusing very carefully on the repairs carried out."

The co-pilot's wife also told Russia's state-controlled NTV that her husband complained about the plane before taking off on the doomed flight. "He complained before the flight that the technical condition of the aircraft left much to be desired," Natalya Trukhacheva said.

Egyptian Airports Chief Adel Al-Mahjoob said on Saturday that the aircraft had passed the required routine inspection before it took off earlier in the day. The airline has also dismissed the possibility that pilot could be responsible for the crash, emphasizing that he had more than 12,000 hours of flying experience, and almost 4,000 hours in planes similar to the Airbus.

Bomb on Board

Dmitry Peskov, spokesman for Russian President Vladimir Putin, told Russian state news agency Itar-Tass on Tuesday that linking the crash to a "terrorist act" was "inappropriate." However, he also said that the airline maintains that the aircraft began to disintegrate in mid-air before it made impact with the ground.

Itar-Tass reported that experts found mysterious "elements not part of the construction of the airplane" at the site of the crash, citing "informed sources in Cairo."

The Russian agency's sources said that this may not necessarily suggest explosive devices were on board as they could be fragments from luggage carried by passengers such as "diving equipment," however details about what was actually found remain scant. Neither Newsweek nor Tass had official confirmation of these findings.

Professor Michael Clarke, director general of the defence and security think tank Royal United Services Institute told the BBC that early reports that the plane split in two "suggests a catastrophic failure, not a mechanical failure," which would imply an explosion on board.

"I'd be much more inclined to think if we have to guess at this stage, it's much more likely to have been a bomb on board rather than a missile fired from the ground," he added.

It is not immediately apparent which theory is most supported by the reports of "uncharacteristic sounds." The source quoted in the Interfax article confirmed previous reports by the airline and flight authorities that the Airbus A321 did not make a distress call and that, according to on-board recordings, the situation on board appeared normal up to four minutes before the aircraft disappeared, when sounds "unusual for regular flight" were recorded.

The source did not describe in what way they were unusual.