How airliner could have crashed in Sinai
Investigators probing the crash of a Russian passenger plane in the Sinai desert will be working on scenarios ranging from terrorism to human error. Among the theories are:

Investigators probing the crash of a Russian passenger plane in the Sinai desert will be working on scenarios ranging from terrorism to human error. Among the theories are:
ISIS downing Experts have set little store in the idea the ISIS group could hit an aircraft flying at 9,000 metres.
“(ISIS) does not have the gear to knock out a plane at 9,000 metres,” said Gerard Feldzer, former director of France’s Air and Space Museum, explaining that would require equipment, such as a mobile radar tracking system and long-range missiles, which ISIS does not have.
Russian transport minister Maxim Sokolov was also quick to dismiss the idea, saying: “Our Egyptian colleagues and aviation authorities... have no information that would confirm such insinuations.”
Terrorist attack “A terrorist attack cannot be ruled out,” according to aviation experts, who argue a bomb could have been placed on board the aircraft.
“In terms of a bomb on the plane, whatever its size, if it explodes at an altitude of 10,000 metres, the plane will completely disintegrate because of the pressure,” said one military expert.
“But something could have happened lower down, or someone on board could have forced the pilot to descend, and an engine could have exploded when the aircraft was lower.”
Mechanical error An official from Egypt’s air control authority said the captain had complained that the communication equipment had failed — he was “aware of a problem”, according to experts.
The Kogalymavia airline, which operates under the name Metrojet, said the aircraft underwent safety checks in 2014, and Russian aviation agency Rosaviatsia said there was “no reason to consider that the cause of the disaster was a technical problem or a crew error”.
Russia used to have a very bad reputation for air safety because of its ageing fleet, but its track record has improved in recent years as major companies, such as Aeroflot, have upgraded their aircraft.
Human error According to Metrojet, the captain, Valery Nemov, had more than 12,000 hours of flying experience, including 3,860 hours on the type of Airbus A321 he was flying at the time. Weather conditions were also fine.
