The black boxes of the Russian plane Antonov, which crashed near Moscow on Sunday, causing the death of its 71 occupants, revealed that the cause of the catastrophe would probably be the formation of ice on the Pitot sensors, one of the elements used to calculate the speed of the apparatus.
These sensors can transmit inconsistent data in the event of ice formation, and disorient pilots. They were already identified as the cause of the crash of the Air France A330 plane from Air France Rio-Paris that fell on the Atlantic in 2009 with 228 people on board.
The An-148 bioreactor of the Saratov Airlines company crashed near Moscow shortly after taking off from Domodedovo airport, with freezing temperatures, towards Orsk, in the Urals.
The 65 passengers and six crew members died.
he Pitot sensors have a device that allows them to be defrosted before starting the flight. But based on the black box data, the Intergovernmental Aviation Committee (MAK) determined that the heating system of the probes was turned off, even though it had been on for the previous 15 flights.
Citing a source among the researchers, the Russian newspaper RBK claims that the aircraft's commander would have decided not to defrost the wings before takeoff despite negative temperatures.
According to a pilot of an An-148 line quoted by RBK, "the crew can perfectly make that decision if, for example, the snow is not wet" and thus provide the company with savings of about $ 2,800.
When rejecting the special treatment, "the crew could buy time, since the flight was a bit delayed, but also money: the procedure can represent the equivalent of 10 to 20 tickets for a flight," explained a source of the investigation to the newspaper. Russian Kommersant.
The black box of the An-148 revealed that there were more and more important divergences between the speeds measured by the different captors in the six minutes that the flight lasted.
This contradictory information led the pilots to deactivate the autopilot at a height of about 2000 meters. But 34 seconds later, one of the probes indicated a zero speed against more than 540 km / h according to another of the sensors.
The device then began to fall.
On Monday, Saratov Airlines announced it was suspending the use of its An-148, a relatively recent model of the Antonov builder that first flew in 2004. The company claimed that the An-148 casualty, operated since 2010 and in January was thoroughly reviewed. , with no faults detected.
The search for remains and bodies mobilizes about a thousand people in an area of several tens of hectares in the district of Ramenski, southeast of Moscow.
Most of the passengers were from the Orenburg region.