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

Abstract

This is a collection of reports that consists of three parts. The author is a Professor of PowerElectrical Engineering, so he focuses on the Tu-154M power electric system and all aspects of the air crashthat relate to electrical equipment and wiring.

Part I discusses the electric power system of the Tu-154M. After brief introduction to aircraft power systems,the results of reverse design and analysis of GT40PCh6 wound-eld synchronous generator including shortcircuit have been presented. An example of failure of GT40PCh6 generator is the re of the Tu-154B-2 onJanuary 1, 2011 before taking o at Surgut airport (ight 7K348). Guidelines for proper investigation ofaircraft electric equipment and wiring after crash have been given. There is no evidence of examinationof most electrical equipment of the Tu-154M No 101 after crash on April 10, 2010. It is now extremelydicult to determine, if the electric power system of the Tu-154M No 101 was operating correctly in thelast seconds of the ight, or not.

Part II analyzes the fuel system and possibility of explosion of fuel-air mixture as a result of arcing and/orstatic electricity in the left wing outer fuel tank of the Tu-154M No 101. Examples of explosions of fueltanks (Boeing 747-131 TWA 800 on June 17, 1996 and Boeing 727-200 at Bangalore Airport on May 42006) have been discussed. Although probability of explosion of fuel in the left wing outer tank due theelectric short circuit, arcing or static electricity is low, this problem should be carefully considered in futureexamination of the wreckage and remaining electrical wiring and equipment.

Part III describes a comparative analysis of hypothetical collision of the Tu-154M No 101 with birch tree,full-scale dynamic crash test of Douglas DC-7 and full-scale dynamic crash test of Lockheed Constellation1649. The analysis pertains to the technical data of the Tu-154M, DC-7 and LC-1649 airliners, dierencesin their construction and conditions of collision/impact.