Flight S7 5220 was en route to Novosibirsk when it encountered an ice problem and plummeted shortly after takeoff.
“After take-off aircraft flew into the clouds and into an area of severe turbulence accompanied by strong freezing. As a result, the plane crashed into a difficult space position,” reads a report from Air Accident Investigation Bureau.
The Airbus A321 twice attempted to return to Magadan Airport but the pilot was unable to refuel to do so – forcing them to continue for nearly five hours to the point of diversion.
The pilots were eventually able to land safely in Irkutsk, near the Mongolian border.
Upon landing, ice on the wings was found, as well as “freezing liquid” in the nose of the plane that interfered with the aircraft’s sensors.
As the AAIB reports, “snow falls continuously and melts during taxiing at below freezing ambient temperatures [had] causes a layer of ice to freeze in the front part of the fuselage interrupting the airflow of the pitot tubes.
“Therefore, taking off with the surface of the fuselage and engine hood covered with a thick layer of snow in freezing and turbulent conditions really jeopardizes flight safety.”
Local police are said to be investigating whether there was a deliberate failure or tampering of deodorant that was used on the fuselage before take-off, according to the aviation blog. View from the Wing.
De-icing is an important part of cold-country flight preparation, with special de-icing fluids made from a heated combination of chemical glycol and water sprayed onto aircraft components to prevent they freeze or fail to take off.
Ryanair and staff at Brindisi airport came under criticism in January 2019 after a plane at the southern Italian airport crashed. filming de-iced with a bucket of water rather than an approved chemical.
https://www.independent.co.uk/travel/news-and-advice/pilots-mayday-russia-deicing-fluid-b1975049.html Pilot claims Thursday after frozen liquid in plane’s nose disrupted flight