Pictured in this image are black box flight recorders recovered from the site of the FlyDubai Boeing 737-800 plane crash.[Photo/IC]

MOSCOW -- An investigation into a passenger jet crash in southern Russia was underway, as experts began to decipher information from one of the two damaged flight data recorders, Russian authorities said on Monday.

The Boeing 737-800, operated by Dubai-based budget carrier Flydubai, crashed early Saturday morning at the Rostov-on-Don airport, that killed all 62 people on board.

Russia's airline regulator said Sunday that experts have opened the flight data recorder which was badly damaged in the crash, and found data extracted from it to be of good quality.

"The memory module has been tested and switched on, and data from it has been copied. Quality of records is good," said the Interstate Aviation Committee in an online statement.

Work had begun to decipher and analyze the copied information, it said. Meanwhile, experts are trying to restore the other badly damaged recorder.

The exact cause of the downing could only be determined after the thorough decoding of the recorders.

At the moment, specialists reconstructed a preliminary picture of the crash, examining several possible causes, including human error, technical failure and unfavorable weather conditions.

"At an altitude of about 900 meters and a speed of more than 400 kilometers per hour, the plane banked left and hit the ground in the left edge of the runway almost vertically, at an angle of 60 degrees," Tass news agency quoted a source with Russia's air transport authorities as saying.

Pilots reported no technical malfunctions during the flight and the landing, and there was no crosswind at the time of the crash, according to the source.

Russian authorities said the aircraft was landing amid high winds and rain that could reduce visibility, and the crash happened as the plane missed the runway in its second landing attempt.

The case now was handed over to a specialized department of Russian Investigative Committee, which has rich experiences on air crash cases, the committee said in an online statement.

Huge amount of work would be carried out by the department, the committee said, adding that investigators have interviewed more than 40 people so far, including victims' relatives, airport staff, FlyDubai's representatives and meteorological experts.

According to the committee, besides the flight recorders of the plane, investigators were also studying flight documentation and the actions of the airport's emergency services.

"After samples are taken for comparative studies, a forensic genetic expertise will be appointed to identify the crash victims," the committee added.

The committee has also allocated a special facility in a bid to reshape the plane with debris at the airport.

Currently specialists have finished clearing the debris from the airport runway and started repairing the damaged part of about 350 square meters, in a bid to reopen the airport by 8 a.m. local time (0500 GMT) on Monday.

"The approximate time of restoring (the runway), if the weather conditions are good, is up to 12 hours," Tass quoted deputy governor of Russia's Rostov region Alexander Grebenschikov as saying.