In July 2010, Russian jet fighters made the first nonstop flights from European Russia to the Russian Far East. By August 2010, according to the Commander-in-Chief of the Russian Air Force Aleksandr Zelin, the average flight hours of a pilot in Russian tactical aviation had reached 80 hours a year, while in army aviation and military transport aviation it exceeded 100 hours a year. On 15 August 2010, the Russian Air Force temporarily grounded its fleet of Su-25 ground attack aircraft to conduct an investigation into a crash that happened during a training mission. The Russian Defence Ministry said that the plane crashed on 6 August 2010, 60 km to the north-west of Step air base in Siberia, according to "RIA Novosti".