On February 7, 2010, Aeroflot Flight 821 crashed in the Ural Mountains during its descent into Perm, Russia, killing all 88 people aboard. The crash was caused by human error, with the pilot misinterpreting the altitude during approach and failing to react to the descent alarm. The incident highlighted the importance of proper crew training and flight safety protocols. Following the crash, the Russian aviation authority took steps to improve the safety of domestic flights. The tragedy marked one of the deadliest air disasters in Russian history.