Lech Kaczynski, the Polish president, will be buried alongside his wife on Saturday at the end of an official week of mourning.
Russian investigators have said there was nothing technically wrong with the aircraft that crashed, killing Kaczynski and 95 others on its way to a memorial service in Smolensk.
Some have suggested that the pilots may have been pressured by people aboard the jet to land quickly so as not to miss the ceremony they were due to attend, which had previously been denied.
Al Jazeera's Jonah Hull has this report.
Source: Al Jazeera