KAZAN, Russia — Russian investigators on Monday combed through the charred fragments of a Boeing 737 jetliner as they tried to determine what caused its crash that killed all 50 people on board.
The plane belonging to Tatarstan Airlines crashed Sunday while trying to land at its home port in the Russian city of Kazan, the capital of the oil-rich province of Tatarstan. The son of the provincial governor and the chief of the local branch of Russia's main security agency were among the victims.
The plane, which was flying from Moscow, crashed while making a second attempt at landing, said Alexander Poltinin, the head of the local branch of Russia's Investigative Committee. He said the investigators are trying to determine why the crew couldn't land at first try.
Poltinin said the investigators are looking into possible pilot error or an equipment failure.
A video taken by an airport security camera that was posted on the Lifenews website showed the jet slamming into the ground at a very sharp angle and exploding in a giant fireball.
The traffic controller at the Kazan airport who contacted the plane before the crash said the crew told him they weren't ready for landing as it was approaching, but didn't specify the problem.
Fragments of the plane littered the tarmac and fire crews spent hours extinguishing the blaze. Poltinin said it could take weeks to identify the remains of some of the victims.
Russian emergency ministry officials said that a British national, Donna Bull, was among the victims.
The investigators have found both of the plane's black boxes, which contain the recording of its systems performance and the crew conversations and are essential for the crash probe. They said the recorders were damaged.
Magomed Tolboyev, a highly decorated Russian test pilot, said on Rossiya television that it wasn't immediately clear why the crew was unable to land at first try in good weather, saying it could be linked to a failure of some of the plane's systems or a crew error.
The plane that crashed was built 23 years ago and had seen service with seven other carriers prior to being commissioned by Tatarstan Airlines.
In 2001, it was damaged in a landing accident in Brazil that hurt no one. The aircraft has been in service with Tatarstan Airlines since 2008.
The company insisted that the aircraft was in good condition for the flight.
The carrier has had a good safety record, but appears to have run into financial problems recently. Its personnel went on strike in September over back wages, and the Kazan airport authority has gone to arbitration to claim what it said was Tatarstan Airlines' debt for servicing its planes.
Investigators on Monday started looking through the company's records as part of the crash probe.
Industry experts have blamed some of recent plane crashes in Russia on a cost-cutting mentality at some of its carriers, with safety sometimes neglected in the run for profits. Insufficient pilot training and lax government controls over industry also have been named among factors affecting flight safety.
Russia's last deadly airliner crash was in December, when a Russian-made Tupolev belonging to Red Wings airline careered off the runway at Moscow's Vnukovo airport, rolled across a snowy field and slammed into the slope of a highway, killing five of its crew of eight who were on board.
A 2011 crash in Yaroslavl that killed 44 people including a professional hockey team was blamed on pilot error.