The pilots ignored de-icing – and failed to warm up the plane's measuring equipment.
That is the announcement from the Russian Accident Investigation Board on Tuesday, which now presents a cause of the accident.
All 71 people aboard the Saratov Airlines An-148 died in the catastrophic crash.
Human error is believed to be the main cause behind the plane crash in Orsk, Russia on Sunday.
This is what accident investigators at the Russian aviation regulatory authority have confirmed, reports AP.
According to the news agency, the plane's pilots never turned on the heater that was supposed to heat the instruments that measure pressure altitude. This led to the speed data that the pilots saw in the cockpit being incorrect.
Turned off autopilot
Investigators have examined the plane's "black box" and found that the plane's two airspeed indicators showed conflicting data about the plane's speed. As a result, the pilots are said to have switched from autopilot to manual control when they heard alarm signals about conflicting speed data.
According to the Russian aviation authority, speeds fluctuated between 0 kilometers per hour and 800 kilometers per hour.
After turning off the autopilot, the pilots carried out a series of maneuvers that led to the plane diving at an angle of 30-35 degrees, the AP reported.
”"Incorrect data from the pilots' airspeed indicators may have been a factor that triggered the special flight situation," the Russian investigators write in their report.
The plane dived
Finally, the plane crashed into a snow-covered field outside Moscow.
"The pilots probably dived with the plane due to the low speeds that were measured, to avoid an overshoot. But since they were at such a low altitude, there was no time to correct the mistake," pilot Andrei Litvinov told Russian media company RBC, according to AP.
Previous reports have shown that the plane's pilots also chose not to undergo screening at Domodedovo Airport in Moscow before departure.
Saratov Airlines stated that the captain of the plane that crashed had over 5,000 flight hours, 2,800 of them in the same model as the plane in question. The co-pilot had 812 flight hours.
Source: aftonbladet.se
