* Russian jet was almost vertical when it hit ground
* Pilot error, technical problems seen as likely causes
* Flags at half mast as Russian region mourns (Adds video footage)
By Alessandra Prentice
KAZAN, Russia, Nov 18 (Reuters) - Russian investigatorssifted through the charred remains of a Boeing 737-500 airlineron Monday in the search for clues about what caused it to crashin a nosedive and burst into flames, killing all 50 people onboard.
Sunday's crash raised new concerns about Russia's poorsafety record as it prepares to host the Winter Olympics in thesouthern city of Sochi in February, an event on which PresidentVladimir Putin has staked much personal political prestige.
Residents of Kazan wiped away tears as they lay flowers atthe airport where the plane crashed in windy weather. Flags flewat half mast in the city 800 km (500 miles) east of Moscow.
In a video that Russian website LifeNews said was footage ofthe crash, a plane descends almost vertically into the tarmacand explodes in a huge fireball.
The Tatarstan Airlines flight from Moscow had been trying toabort its landing when it nosedived into the runway, killing all44 passengers and six crew. "The plane just fell," TransportMinister Maxim Sokolov told reporters.
"The plane was vertical, practically vertical."
Sokolov added the black box flight recorders, which werefound on Monday, would need to be analysed for more information.
"The whole town is in mourning," said Elvira Khadiulina, anursery-school teacher who came to the airport to mourn friendswho died in the crash. "These people were only a few minutesfrom being safe on the ground."
Tatarstan Airlines said it was grounding all its Boeing 737planes pending an investigation into the crash.
"The main versions are pilot error and technical problems,including equipment failure," Alexander Poltinin, a seniorregional investigator, said of the crash.
He said the plane's fuel tank had exploded on impact and itcould take weeks for all the dead to be identified in thewreckage, scattered over a wide area.
"There are mostly just fragments of bodies, few corpses,"local health ministry official Nail Nigmatullin told theInterfax news agency.
The son of the president of the oil-rich province ofTatarstan and the regional head of the FSB intelligence servicewere named among those killed. The dead also included twoforeigners, a Briton and a Ukrainian.
"It's unimaginable - it's awful, just awful," said a man whogave his name as Dmitry as he left flowers at the airport gate."Everyone already knows what state our national aviation is in,so ... this isn't surprising."
Russia and the other former Soviet republics combined haveone of the world's worst air-traffic safety records, with atotal accident rate almost three times the world average in2011, according to the International Air Transport Association.
In Soviet times, flag carrier Aeroflot had avirtual monopoly of the airline industry, but after the collapseof the Soviet Union, many small private companies emerged.
IATA said last year that global airline safety had improvedbut accident rates had risen in Russia and the ex-SovietCommonwealth of Independent States.
The government says it is confident about security andsafety matters at the Sochi Olympics and the city'sinternational airport has been upgraded for the Games.
There had been no technical problems reported with theleased 23-year-old plane prior to the flight and regularmaintenance between flights had been conducted, officials said.
Boeing said in a statement it was prepared to providetechnical assistance to the investigators.
Kazan is the capital of the largely Muslim region ofTatarstan. There was no suggestion of foul play.
A new runway was built at the airport before the WorldUniversity Games, held in the city in July. Kazan is one of thevenues for the soccer World Cup that Russia is hosting in 2018. (Additional reporting by Mikhail Antonov and Nikolai Isayev,;Writing By Timothy Heritage, Alissa de Carbonnel and GabrielaBaczynska,; Editing by Gareth Jones and Robin Pomeroy)
- UK International News
- Tatarstan Airlines