A 21-year-old UTair ATR 72-200 crashed after takeoff from Tyumen in western Siberia on Monday, killing 31 of the 43 people on board. UTair said the plane crashed while trying to make an emergency landing shortly.

Preliminary analysis of the "black box" flight recorders showed both engines were working when the plane hit the ground, the Interstate Aviation Committee, which investigates air crashes in 12 ex-Soviet republics, said on Tuesday.

The plane rose to an altitude of about 210 meters after takeoff, then dipped to its right side and then sharply left as it crashed, the Moscow-based committee said.

UTair director Andrei Martirosov said there were no grounds for doubt so far that the plane was in a good technical condition and that the decision was made to reassure passengers.

UTair's website says it has three of the twin-engine, turbo prop planes. The statement said it would use ATR 72-500s built last year to replace the grounded planes.

ATR is an equal partnership between two major European aeronautics players, Alenia Aermacchi, a Finmeccanica (SIFI.MI) company, and EADS (EAD.PA).

The federal Investigative Committee said the plane had notched up 35,000 flying hours since going into operation in 1992 and had not had a "serious" technical check since 2010.

The crash was the worst in Russia since a Russian-made Yak-42 slammed into a riverbank near the city of Yaroslavl after takeoff on September 7, 2011, killing 44 people and wiping out the Lokomotiv Yaroslavl ice hockey team.

Russia and the former Soviet republics had one of the world's worst air-traffic safety records last year, with a total accident rate almost three times the world average, the International Air Transport Association said.

(Writing by Steve Gutterman; Editing by Alison Williams)

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