An official Polish report says pilot error was the main cause of the air crash in Russia which killed President Lech Kazynski and other senior officials.
Ninety-two people were killed in the crash on 10 April last year.
The report also says that Russian air traffic control gave the crew incorrect landing instructions as they prepared to land in Smolensk.
A Russian report, issued earlier this year, blamed only pilot error.
Defence Minister Bogdan Klich resigned on Friday after the report was issued.
All those on board the TU-154 Tupolev, who included the country's military and political elite, were killed when their airliner crashed while trying to land in heavy fog.
They had been on their way to a memorial for the victims of Katyn, where 20,000 Polish officers were massacred by Soviet forces in 1940.
