Two passengers were in the cockpit of the Polish plane that crashed in western Russia last month, killing President Lech Kaczynski and dozens of other senior government officials, investigators said.
One of the voices has been identified but cannot be made public until the criminal investigation of the crash is completed, said Tatyana Anodina, the head of Russia's Interstate Aviation Committee (IAC), which is leading the investigation.
Preliminary findings show that the pilots should not have attempted to land in Smolensk on April 10th because visibility was too low due to heavy fog, Ms Anodina said on state television today.
Technical failure, explosion and terrorism were all ruled out as possible causes, she said.
Mr Kaczynski was flying to Smolensk to honour the 22,000 Polish prisoners of war killed by Soviet dictator Josef Stalin's secret police in the Katyn forest in 1940. All 96 people on board died in the crash, including Polish central bank Governor Slawomir Skrzypek and the country's top four military leaders.
The left wing of the Russian-built Tupolev Tu-154 clipped a birch tree as it descended and the airplane disintegrated in five or six seconds, said Alexei Morozov, one of the members of the investigation panel.
Russian air-traffic officials said at the time that the military pilot of the plane ignored warnings to divert to another city, leading to speculation that Mr Kaczynski, as commander and chief, ordered the plane to land.
Edmund Klich, head of a Polish committee that analyses airplane crashes and also participating in the IAC examination, said recordings showed the voices of non-crew members were heard in the background 16-20 minutes before the crash.
"I do not believe that this will have a decisive influence on the cause of the catastrophe," Mr Klich said. "But this is my personal opinion."
He added that the presence of non-crew in the cockpit did not break any rules since government and military planes are governed by different standards. Passengers are not allowed in the cockpits of civilian aircraft.
In August 2008, the pilot flying Mr Kaczynski to Georgia refused an order to land in Tbilisi because of the country's war with Russia, diverting instead to Azerbaijan. Kaczynski later criticized the action, saying that someone who decides to be an officer "cannot be timid," the Gazeta Wyborcza newspaper reported at the time.
Bloomberg