Russia on Monday sought answers for the latest deadly plane crash to raise alarm about the safety of its civil aviation, with investigators focusing on a fault with the 23-year old plane or pilot error as the likely cause for the disas

Russia on Monday sought answers for the latest deadly plane crash to raise alarm about the safety of its civil aviation, with investigators focusing on a fault with the 23-year old plane or pilot error as the likely cause for the disaster that killed 50.
  
The Tatarstan Airlines Boeing 737-500 crashed on landing at the airport in the Volga city of Kazan after a flight from Moscow's Domodedovo airport Sunday night, killing all 44 passengers and six crew on board, the emergencies ministry said.
  
"The main versions of what happened are an error in piloting and technical factors, including a technical failure," the head of the transport Investigative Committee for the Volga region Alexander Poltinin was quoted as saying by Russian news agencies.
  
He confirmed that that the crash occurred while the aircraft was making a second attempt at landing and said the investigation would have to consider why the pilot had not managed to land the first time in reasonable weather conditions.
  
The disaster claimed the lives of the son of the leader of the Tatarstan region, Irek Minnikhanov, and the head of Russia's FSB security service in Tatarstan, Alexander Antonov. Also among the dead was a Briton, Donna Carolina Bull, 53, and a Ukrainian national, the emergencies ministry said. The rest of the victims are all believed to be Russian citizens.
  
For unexplained reasons, the plane landed around 150 metres (500 feet) away from the main runway at Kazan airport and then exploded, strewing debris over hundreds of metres, Russian state television said.