Pilot errors, onboard failures possible Aeroflot crash factors

Failure in communication and loss of automated flight control system caused the Aeroflot Superjet 100 plane to return to the airport on Sunday, during which it caught fire and crashed in an emergency landing, Moscow's Sheremetyevo Airport said on Tuesday.

According to the airport, the plane took off at 18:02 local time, and at 18:12, the flight commander reported a failure in radio communication to the airport's dispatch, requesting landing at the airport.

One minute later, a second communication failure and the malfunction of the plane's automated flight system were reported. At 18:30, the plane landed at the Sheremetyevo tarmac, after which it caught fire.

In the minute following the plane's landing, the emergency alert was issued and the plane's emergency slides were deployed to enable the passengers to evacuate.

The first two firefighting squads arrived at the crash site at 18:32, while four more approached the plane at 18:33. The airport rescue teams entered the burning plane at 18:35. The fire was fully extinguished at 18:48.

Russian media reported that the investigators were considering pilot error as the cause of the crash-landing that killed 41 people.

Russian television Ren TV posted what it said was the conversation between the pilots and air traffic control, which showed that the pilots remained calm as one of them requested emergency landing, but did not assess the situation as critical.

The airport noted that after the emergency alert is issued, the emergency and rescue teams must arrive at the crash site within three minutes. Twenty-six emergency workers, one vehicle of the gas and smoke protection services, as well as four ambulances were involved in the rescue operation, Tass News Agency reported.

Pilot Denis Yevdokimov told media lightning strike shortly after takeoff caused the aircraft to lose communications and forced the emergency landing.

In the transcript of his communication with air traffic control, Yevdokimov said: "We request return (due to) loss of radio communications."

He said that the plane had been hit by lightning.

The plane's automatic flight control system was not working, the pilot then added. He confirmed he was going to land using only instruments and told air traffic control that "help is needed".

However, sources in the investigation told Kommersant newspaper that the Aeroflot pilots made a number of errors including flying into a thunderstorm and landing with a full tank rather than circling to use up fuel.

Various sources told the business daily RBK that the pilots opened a cockpit window, potentially fanning the flames, and failed to turn off engines immediately after landing.

Investigators are still examining the black boxes from the plane and have so far given no official reason for the crash.