Dense fog and foul weather but also human error, in particular the pilot's reportedly obstinate refusal to divert the flight, have been cited as reasons for the plane crash in Russia in which Poland's ultra-conservative President Lech Kasczynski and 96 others were killed.
Poland has declared a week's official mourning to mark the accident which has devastated the upper echelons of the country's political and military establishments.
The 61-year-old Mr. Kaczynski was elected president in 2005 at the same time that his twin brother Jaroslaw, took over as Prime Minister at the head of a government led by the ultra-conservative Law and Justice Party.
The identical twins' espousal of laissez-faire policies and their stubborn opposition to legislation favouring abortion because of their deeply-held Catholic beliefs, made them widely unpopular in Europe. An open Euro skeptic, Mr. Kasczynski was one of the last EU leaders to put his signature to the European Union's Lisbon Treaty which aims to streamline EU institutions.
Mr. Kaczynski's profound distrust and hatred of Russia and the ties the former German Chancellor, Gerhard Schroeder, forged with that country affected Poland's relations with Russia, with Germany and by extension with other EU nations.
Mr. Kasczynski was an anti-communist militant even during his student days and he was one of the early members of the Solidarity free trade union movement in the 80s that contributed to the fall of communism. Even after Poland freed itself from the Soviet yoke to become a democratic, market-friendly member of the European Union, Mr. Kasczynski's witch hunt of former communist sympathisers and party officials continued.