A Saratov Airlines flight crashed near Moscow last Sunday, Feb. 11, plummeting into the snowy terrain and killing all 71 people on board. State-run Russian media announced that the commercial airplane did not report any problems before abruptly disappearing from radar shortly after takeoff from Moscow’s Domodedovo Airport.

The Antonov An-148 aircraft was carrying 65 passengers, including three children of ages 5, 13 and 17, and six crew members. The aircraft was headed to the Russian city of Orsk, near the border with Kazakhstan, but went down in the in Ramenskoye District right outside of Moscow.

Initially, the cause of the crash was unclear. The plane was reported to be in good condition before takeoff according to routine inspections. The Moscow region has had some of its heaviest snowfall in decades, so the weather was initially considered as a possible factor in this crash.

However, after an extensive investigation conducted by the Interstate Aviation Committee, it was found the crash occurred after the pilots saw contradicting data on the plane’s two airspeed indicators. This was most likely a result of the pilot’s failure to turn on the heating unit for the plane’s pressure measurement equipment prior to takeoff, which would allow ice to build on the sensors and skew speed measurements.

“The recent crash was a terrible incident, but unfortunately it has not received a lot of international media attention. I hope people will come together and support those who lost loved ones in this disaster,” freshman Natalie Falls said.

Without accurate data on the speed of the aircraft, it would be easy for the pilots to accidentally reach unsafe speeds and lose control of the aircraft, resulting in a crash. Data recovered at the scene of the accident, including recordings of the pilots’ conversations as the plane went down, supports this theory.

First responders found wreckage spread across a wide area of the snowy terrain. “The scatter of fragments of the aircraft and bodies of dead passengers occupies a large territory; the radius is not less than 1 kilometer (0.6 miles),” stated a spokesperson for the Investigative Committee of Russia.

This tragedy breaks a 440-day streak without a casualty on a commercial passenger jet — the longest stretch in modern aviation history.

President Vladimir Putin commented on the event shortly after it occurred, offering his “deepest condolences” to the families of the victims. He also facilitated the federal investigation into the case to determine the cause of the accident and ensure it would not take place again.