The crew of the Pulkovo Airlines Tupolev Tu-154 that crashed in Ukraine on 22 August deep-stalled and spun while trying to climb over towering storm clouds, according to Russia's interstate aviation committee MAK. Meanwhile the Russian government, concerned that airline safety in the country is worsening, has set up a committee to examine the issues.
MAK has firmly indicated that weather conditions contributed to the loss of the aircraft and all 170 passengers and crew, and has issued a set of recommendations for pilots operating in the vicinity of thunderstorms.
When the Tu-154M crew saw the storm cells ahead they tried to "jump over" them, simultaneously altering course laterally by 20km (11nm), according to Aleksandr Neradko, head of Russia's Federal Aeronavigation Service. He says the aircraft climbed from the cruise altitude of 35,100ft (10,700m) to a maximum height of 39,500ft, and at that point the aircraft stalled and entered a spin with a high angle of attack.
MAK says that crews should "thoroughly analyse" weather conditions and, if thunderstorm activity is present, select appropriate routes and altitudes based on the nature and displacement of the storm cells. Pilots should ensure any strategy to evade storm activity by climbing above the cloud strictly takes account of flight envelope limitations, such as the maximum permissible bank, and the risks associated with turbulence, which can cause rapid variations in the aircraft's vertical acceleration and its angle of attack, and therefore increase its vulnerability to stalling.
It adds that civil aviation authorities should arrange for pilot training that draws attention to the issues associated with operating aircraft at maximum permissible altitudes and angles of attack, and during turbulent weather conditions. MAK says that the early recommendations and release of information is designed to allow aircraft operators and other air transport organisations to take "operational preventative measures" to improve flight safety.
At a special Russian government meeting about aviation safety on 31 August, the minister of transport Igor Livitin said the thunderstorm front was unusually high, extending up to 15km, so the aircraft did not have the performance to have overflown it. He also released the timeline for the Pulkovo accident flight:
15:05 the aircraft takes off from Sochi airport on the Black Sea
15:22 it enters Ukrainian airspace
15:37 the crew reports turbulence and transmits an emergency call
15:39 radar contact lost.
At the meeting the Russian government chairman Mikhail Fradkov appointed Sergei Ivanov, a vice-premier and defence minister, to head a governmental body that "shall take necessary structural actions" to address what he has interpreted as the worsening aviation safety situation in Russia.
Before the Pulkovo Tu-154 crash there was a fatal accident involving an S7 (formerly Sibir) Airlines Airbus A310-300 at Irkutsk, Siberia, when it overran the runway by a considerable distance and collided with buildings, killing 124 people. Also in Russia, but involving an Armenian airline, an Armavia Airbus A320 crashed on approach to Sochi on 3 May, killing all 113 people on board. In 2005 there were four fatal accidents involving small regional carriers.
Ivanov says he will specifically address two issues:
■ the proper certification of spare parts for civil aircraft, because there is increasing evidence that "fake" parts are entering the market
■ the improvement of meteorological support for aviation. He says inaccurate weather reports are common.