Although the exact cause is still unknown, the crash of a Tupolev jet in Germany is another sad chapter in Russia's post-Soviet air history.

The former Soviet air fleet has been plagued by chronic safety problems since the 1991 collapse of the union and the break-up of the former state airline Aeroflot into some 400 companies.

Accidents involving former Soviet aircraft have generally been attributed to cash shortages, which lower already poor maintenance standards and place extra pressure on air crews.

Safety concerns

Ageing aircraft Poor maintenance Obsolete air traffic control system

Concern is frequently expressed about safety standards in many of the small airlines, many of them using some of the older planes shed by the giant Aeroflot.

The ageing Tupolev 154 remains popular with the airlines of the former Soviet Union, despite the emergence of safety fears following numerous crashes.

More than 1,000 Tu-154s have been built and most remain active.

Apart from ageing aircraft and insufficient maintenance, serious concern has been expressed over the air traffic control system in the region. Much of its equipment is obsolete and was now incompatible with the international air navigation system

However, in recent years, the safety record of former Soviet airlines has improved, and the last serious crash involving an airliner from the former Soviet Union was in 1997.

Some of the more serious passenger plane crashes of recent years include:

• 15 December 1997: A Tu-154 from the former Soviet republic of Tajikistan crashes in the United Arab Emirates, killing 85 passengers and crew.
• 18 March 1997: 50 passengers and crew die when the tail of their An-24 charter plane breaks off in mid-air while en route to Turkey.
• 29 August 1996: A Tu-154 passenger plane carrying Russian and Ukrainian miners and their families to work on Norway's Arctic island of Spitzbergen crashes into a mountain top, killing all 143 people on board.
• 7 December 1995: A Tu-154 with 97 people aboard disappears en route to the far eastern city of Khabarovsk.
• 26 September 1994: A Yak-40 airliner crashes while trying to reach an airport in Siberia to make an emergency landing in bad weather. All 26 people on board die.
• 23 March 1994: An Airbus A-310 belonging to Aeroflot crashes near Novokuznetsk, killing 70 people.
• 3 January 1994: All 124 people on board a Tu-154 plane are killed when it crashes in Siberia, as well as a farmer on the ground.