The RusAir Tu-134 plane had taken off from Moscow and was moments from landing at the Petrozavodsk airport when it slammed into a nearby highway just before midnight Monday, Emergencies Ministry spokeswoman Oksana Semyonova told The Associated Press.
Preliminary information shows the crash was caused by the jet's pilot missing the runway in adverse weather conditions, Deputy Prime Minister Sergei Ivanov said Tuesday.
Russia's top investigative agency said it was also looking into whether technical problems with the 31-year-old plane might have contributed to the crash. There were no suspicions of foul play.
The plane's approach was too low, so it clipped a tree and then hit a high-power line - causing the airport's runway lights to go off for 10 seconds - before slamming into the ground, Sergei Izvolsky, a spokesman for the Russian air transport agency, told the AP.
The Emergencies Ministry said 44 people were killed, including four with dual U.S. and Russian citizenship. Local residents rescued the eight survivors, including a mother, her 9-year-son and 14-year-daughter. They were hospitalized in critical condition in Petrozavodsk.
Petrozavodsk is near the Finnish border, about 400 miles (640 kilometers) northwest of Moscow. The plane crashed about 100 yards (meters) from a small village, but no casualties were reported on the ground.
Speaking from the crash site, the federal air transport agency chief, Alexander Neradko, said the plane appeared to be intact when it hit a 15-meter (50-foot) pine tree. "There was no sign of a fire or explosion on board the plane before the impact," he said.
Sergei Shmatkov, an air traffic controller who oversaw the plane's approach, told lifenews.ru that visibility near the airport was bad - close to the minimum level at the time of the crash - but the pilot still decided to land.
"The crew continued their descent at a moment when they already should have begun a second run," he said.
Shmatkov said he ordered the crew to abort the landing the moment the runway lights went off but it already was too late.
Despite the plane's age, RusAir said it was in good working order.
The twin-engined Tu-134, along with its larger sibling the Tu-154, has been the workhorse of Soviet and Russian civil aviation since the 1960s with more than 800 planes built. The model that crashed was built in 1980, had a capacity of 68 people and a range of about 2,000 kilometers (1,240 miles).
Aviation experts said pilot error appeared to be the likely cause.
"There is a strict rule: If you are on a glide path and you have not made reliable eye contact with lights on the ground, there is no choice but to put the engines at full throttle and make another run," said Oleg Smirnov, a former deputy civil aviation minister who now heads the nonprofit Partner of Civil Aviation Foundation.
Magomed Tolboyev, a highly decorated Russian test pilot, said the Tu-134, while outdated, has a good reputation for reliability and agreed that human error was the most likely cause.
"The human factor is always key, especially now, when the level of crew training is very low and not controlled by the government," Tolboyev told the Interfax news agency.
Video footage showed charred plane fragments, including engines and landing gear, strewn around the highway less than one kilometer (half a mile) short of the runway. Amateur video showed the plane consumed by fierce flames overnight.
The plane was carrying 52 people, including nine crew members, according to the Emergencies Ministry. Four of the dead had dual U.S. and Russian citizenship - Lyudmila Simanova, Alexander Simanov, Yelizaveta Simanova and Yekaterina Simanov - but the U.S. Embassy had no immediate information on them.
Other victims a Swedish citizen, a Dutchman, two Ukrainians, Russian Premier League soccer referee Vladimir Pettay and one man with dual Russian-German citizenship.
The local Emergencies Ministry branch said radio contact with the pilot was lost at 11:40 p.m. local time. The plane's flight data recorders have been recovered.
Russian President Dmitry Medvedev and Prime Minister Vladimir Putin offered condolences to the victims' families, and the transport minister flew to the crash site to oversee the investigation. Putin was attending the Paris Air Show on Tuesday to support dozens of Russian firms seeking sales contracts.
In recent years, Russia and the other former Soviet republics have had some of the world's worst air traffic safety records, according to official statistics. Experts blame the poor safety record on the age of the aircraft being used, weak government controls, poor pilot training and a cost-cutting mentality.
In 2006, three crashes - two in Russia and one in Ukraine - killed more than 400 people.
Polish President Lech Kaczynski was among 96 people killed when his Tu-154 crashed in heavy fog while trying to land near the western Russian city of Smolensk in April 2010.
Ivanov, who accompanied Putin to Paris, said that Tuesday's crash closely resembled that of the Polish plane, which also was apparently caused by pilot error. He said many Russian airlines lack the funds needed to replace their aging Tupolev planes, Interfax reported.
The Russian flag carrier Aeroflot has withdrawn all its Tupolevs from service and almost exclusively relies on Boeings and Airbuses. On Tuesday, it announced orders for eight more Boeing 777 airliners at the Paris Air Show.
A day before the crash, the International Air Transport Association noted that Russia has recently made progress on air safety, with none of Russia's 13 largest air carriers suffering a deadly accident in the past three years.
David Nowak, Vladimir Isachenkov and Mansur Mirovalev in Moscow and David Rising in Berlin contributed to this report.