The Commission of the Ministry of Industry and Trade of the Russian Federation which was set up to investigate the causes of the An-148-100 (side number 61708) fatal accident happened on March 5, 2011 in the area near Garbuzovo village of Alekseevskiy district in Belgorod Region completed its work. Specialists and experts of a number of companies and institutes participated in the work of the commission including the specialists of the JSC United Aircraft Corporation’s enterprises (JSC Voronezh Aircraft Manufacturing Company, JSC IRKUT Corporation), as well as the experts and representatives of ANTONOV Company, JSC Aviaprom, the Central Aerohydrodynamic Institute (TsAGI), the Flight Research Institute named after M.Gromov, JSC Motor Sich and a number of other companies. This join work provided for in-depth and unprejudiced analysis of all aspects of the fatal accident.

According to the Act of the Commission the accident was caused by unintended overspeeding during extreme sweep down. The aircraft speed exceeded the maximum indicated airspeed (which is higher than certification airspeed) by 110 km/h. This caused aircraft deformation and low-frequency vibration on all its axes, and stressed the aircraft beyond certification limit loads. As a result, the aircraft broke-up in the air and consequently crashed on the earth.

Moreover, the commission determined a number of factors relating the fatal accident:

• The level of coordination and promptness (response to orders) of the crew members’ actions was insufficient;
• Deviation from the recommendations of the Flight Crew Aviation Manual in case of sweep down;
• The key speed indicators in the cockpit showed false instrumental speed data in the flight modes that are not typical in accordance with the Flight Manual.

The Investigative Commission did not find any factors influencing flight safety of the An-148 aircraft being in commercial operation. Thus, there is no need to suspend commercial services of the An-148.