Incident Overview

Date: Saturday 1 January 2011
Aircraft Type: Tupolev Tu-154B-2
Owner/operator: Kolavia
Registration Number: RA-85588
Location: Surgut Airport (SGC) – ÿ Russia
Phase of Flight: Standing
Status: Destroyed, written off
Casualties: Fatalities: 3 / Occupants: 134
Component Affected: The TKS233DOD electrical contacts, specifically the connections between generator #2 and #3, are the primary component affected.The TKS233DOD electrical contacts, specifically the connections between generator #2 and #3, are the primary component affected.
Investigating Agency: MAKMAK
Category: Accident
A Tupolev 154B-2 passenger jet, registration RA-85588, crashed in an accident at Surgut Airport (SGC), Russia, resulting in the deaths of twelve six passengers and eight crew members. The aircraft was operating a flight KGL348 from Surgut to Moskva-Domodedovo Airport (DME). Three fatalities occurred, and approximately thirty-two passengers sustained serious injuries. Initial reports indicate a short circuit occurred during the start-up of the aircraft’s engines, triggered by the connection of AC generators to the aircraft’s electrical system after engine start. A fire erupted in the rear of the aircraft, rapidly spreading through the cabin. The crew initiated an evacuation. Interstate Aviation Committee reports that engines 1, 2, and 3, and the APU, were not the primary source of the fire. The fire originated in the rear of the aircraft near frame 62-65, caused by an electrical arc generated by excessive electrical currents when two generators were connected without synchronization.A Tupolev 154B-2 passenger jet, registration RA-85588, crashed in an accident at Surgut Airport (SGC), Russia, resulting in the deaths of twelve six passengers and eight crew members. The aircraft was operating a flight KGL348 from Surgut to Moskva-Domodedovo Airport (DME). Three fatalities occurred, and approximately thirty-two passengers sustained serious injuries. Initial reports indicate a short circuit occurred during the start-up of the aircraft’s engines, triggered by the connection of AC generators to the aircraft’s electrical system after engine start. A fire erupted in the rear of the aircraft, rapidly spreading through the cabin. The crew initiated an evacuation. Interstate Aviation Committee reports that engines 1, 2, and 3, and the APU, were not the primary source of the fire. The fire originated in the rear of the aircraft near frame 62-65, caused by an electrical arc generated by excessive electrical currents when two generators were connected without synchronization.

Description

A Tupolev 154B-2 passenger jet, registered RA-85588, was damaged beyond repair in an accident at Surgut Airport (SGC), Russia. There were 126 passengers and eight crew members on board. The airplane operated on a flight KGL348 from Surgut Airport (SGC) to Moskva-Domodedovo Airport (DME). Three passengers died and about 32 were seriously injured. The airplane was destroyed by fire. Initial reports indicate that the airplane had been towed to the main taxiway for engine startup. A short circuit occurred while the AC generators were connected to the aircraft’s electrical system after start-up of the engines. A fire erupted in the rear, spreading quickly through the main cabin. The crew shut down the engines and initiated an evacuation. The Interstate Aviation Committee reported that engines no. 1, 2 and 3 and the APU were not the source of the fire. The fire started in the rear of the aircraft in the area of frames 62-65. The cause of the fire was an electrical arc produced by electrical currents exceeding ten to twenty times the nominal loads when two generators not synchronised with each other were brought online but got connected together instead of being connected to parallel busses. The unsynchronised operation of the generators can be attributed to: – Poor technical conditions of contacts TKS233DOD responsible for connecting the generators with the electrical busses, that were damaged by prolonged operation without maintenance. A contact normally open was welded and fractured insulation material moved between contacts that are normally closed. These abnormal contact positions led to the connection between #2 and #3 generators. – Differences in the schematic diagrams of generator 2 and generators 1 and 3. When the switch is moved from “check” to “enable” with no delay in the “neutral” position generator 2 is brought online without time delay which leads to increased wear of normally closed contacts in the TKS233DOD unit. – The specific design of the electrical systems to ensure power supply to each bus from either the APU or either engine integrated drive generator.

Source of Information

http://en.rian.ru/russia/20110101/162017397.html, http://www.mak.ru/russian/investigations/2011/tu-154b_ra-85588.html, http://www.mintrans.ru/news/detail.php?ELEMENT_ID=15429http://en.rian.ru/russia/20110101/162017397.html, http://www.mak.ru/russian/investigations/2011/tu-154b_ra-85588.html, http://www.mintrans.ru/news/detail.php?ELEMENT_ID=15429

Primary Cause

Poor technical conditions of the TKS233DOD contacts, specifically the damaged insulation material and welding of contacts, resulted in a connection between generator #2 and #3, leading to an electrical arc.Poor technical conditions of the TKS233DOD contacts, specifically the damaged insulation material and welding of contacts, resulted in a connection between generator #2 and #3, leading to an electrical arc.

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