MOSCOW (AP) - Russian aviation experts ran into technical problems Friday as they began examining the flight data recorders from a plane crash killed 43 people.
Investigators have not yet been able to pinpoint what caused the chartered Yak-42 jet to crash Wednesday into the banks of the Volga River shortly after takeoff from an airport near Yaroslavl, 150 miles (240 kilometers) northeast of Moscow.
The magnetic tapes holding the flight information in the data recorders were still wet and investigators can't begin deciphering them until after they dry out, the Interstate Aviation Committee said on its website Friday.
Aviation authorities are now running checks on all the approximately 60 Yak-42 jets currently in service in Russia.
The crash killed 43 people, including 36 players, coaches and staff of the Lokomotiv Yaroslavl ice hockey team, many of whom were European national team and former NHL players. It was one of the worst aviation disasters ever in sports, shocking Russia and the world of hockey.
The team had been heading to Minsk, Belarus to play its opening game of the Kontinental Hockey League season.
The two crash survivors - player Alexander Galimov and crew member Alexander Sizov - were still in critical condition Friday after being transferred to Moscow for treatment. Hospital officials said Galimov has suffered burns to 90 percent of his body and has been placed in a medicated coma to help ease the healing process.
Tunoshna airport, where the doomed Yak-42 took off, has been allowed to resume operations, but planes were being barred from using locally produced fuel. Yaroslavl governor Sergei Vakhrukov said Friday that checks on the fuel used by the plane would be part of the crash investigation.
The crashed jet was built in 1993 and one of its three engines was replaced a month ago, transport officials said. According to initial information gleaned by investigators, two of the aircraft's engines were operating right up until the plane crashed.
Flights on all Yak-42 jets will likely face severe disruptions over the next few days as authorities carry out the safety inspections. An Associated Press reporter was among the passengers ordered to disembark Friday from a Yak-42 bound on an internal flight from Moscow.
Checks on Yak-42, which began service since 1980, are likely be only the start of sweeping reforms to Russia's aviation industry called for by President Dmitry Medvedev, who even before the crash announced plans to take aging Soviet-built planes out of service starting next year.
Vakhrukov suggested that goal would fraught with difficulties.
"We fully understand that the number of planes that we are able to produce is clearly not enough to replace the huge number of old, worn-out planes that our airlines fly today," he said.
Experts blame Russia's poor aviation safety record on an aging fleet, weak government controls, poor pilot training and a cost-cutting mentality.
Lynn Berry in Yaroslavl, Russia, and Natalia Vasilyeva in Moscow contributed to this report.