A Boeing 737 plane carrying 78 passengers plus crew landed safely at the main airport in Russia's second city of St Petersburg on Wednesday after one of its engines failed.

"The plane made a safe landing ... no passengers were injured," Russian airline UTair, which operated the flight, said in a statement.

UTair is Russia's third-largest airline by passenger numbers and is more than 60 per cent owned by a pension fund of oil company Surgutneftegaz. It carried 11.2 million passengers in 2014, up 7 per cent on 2013.

The economic crisis has hit the company hard - it is being sued by a number of creditors over unpaid debts and defaulted on seven bond issues worth a combined 10 billion roubles late last year.

It has asked for state guarantees to help restructure its debt which stands at around 168 billion roubles ($2.95 billion), including 85.2 billion in leasing liabilities. – Reuters