Polish report has found that Russia was partly to blame for the air crash last year which killed then-President Lech Kaczynski.
It said that pilot error was the main reason for the crash, but that air controllers and poor lighting at Smolensk were also at fault.
The crash killed 96 people and has been a source of tension between the two countries.
A Russian report released in January laid full blame on Poland.
But Poland, while accepting some of the findings, said that Moscow's report was "incomplete".
All those on board the TU-154 Tupolev, who included officials spanning 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.
The report by Warsaw said the pilot had lacked experience in landing aircraft in adverse weather conditions, and the crew was not adequately equipped.
It also found that airport lighting was "defective and incomplete", while a landing zone official had given "erroneous information" to the crew as they prepared to land in poor weather at the Russian city of Smolensk.
Air traffic controllers misinformed the crew about their true altitude during the approach and gave a crucial warning too late, it said.
In its report earlier this year, Russia had said the crash was due to pilot error and said the crew had taken unjustified risks under pressure from their superiors.
However, the Polish report said there was no evidence that Lech Kaczynski or anyone else on board had put pressure on the pilots to act against their wishes.
Russia's handling of the disaster had originally been widely commended, but the issue later became a source of contention between the two nations.
Jaroslaw Kaczynski, the twin brother of the later president and opposition politician, has previously accused Prime Minister Donald Tusk's government of a cover-up with Moscow. Mr Tusk strongly denies the claims.
Poland's first couple - along with other leading political and military figures - had been on their way to a memorial ceremony for the World War II Katyn massacre when the crash took place on 10 April. There were no survivors.