Selected Technical Aspects of Tu-154M Smolensk Air Crash on April 10, 2010

This is a collection of reports that consists of three parts. The author is a Professor of Power Electrical Engineering, so he focuses on the Tu-154M power electric system and all aspects of the air crash that relate to electrical equipment and wiring. Part I discusses the electric power system of the Tu-154M. After brief introduction to aircraft electric power systems, the results of reverse design and analysis of GT40PCh6 wound-field synchronous generator including short circuit have been presented. An example of failure of GT40PCh6 generator is the fire of the Tu-154B-2 on January 1, 2011 before taking off at Surgut airport (flight 7K348). Guidelines for proper investigation of aircraft electric equipment and wiring after crash have been given. There is no evidence of examination of most electrical equipment of the Tu-154M No 101 after crash on April 10, 2010. It is now extremely difficult to determine, if the electric power system of the Tu-154M No 101 was operating correctly in the last seconds of the flight, or not. Part II analyzes the fuel system and possibility of explosion of fuel-air mixture as a result of static electricity and/or arcing in the left wing outer fuel tank of the Tu-154M No 101. Examples of explosions of fuel tanks (Boeing 747-131 TWA 800 on June 17, 1996 and Boeing 727-200 at Bangalore Airport on May 4 2006) have been discussed. Although probability of explosion of fuel-air mixture in the left wing outer tank due to static electricity, electric short circuit or arcing is low, this problem should be carefully considered in future examination of the wreckage and remaining electrical wiring and equipment. Part III describes a comparative analysis of full-scale dynamic crash test of Douglas DC-7, full-scale dynamic crash test of Lockheed Constellation 1649 and hypothetical collision of the Tu-154M No 101 with birch tree, The analysis pertains to the technical data of the DC-7, LC-1649 and Tu-154M airliners, differences in their construction and conditions of collision/impact.