Mumbai: A revival plan proposed by India’s troubled Kingfisher Airlines is not enough to get the carrier back in the skies, an aviation ministry official said on Friday.

Kingfisher has been grounded since October and boss Vijay Mallya hopes to restart limited operations in March, but the government is not convinced by his firm’s proposals.

“The airline has to demonstrate its capability to run efficiently. It has not provided a convincing plan to resume operation,” an official who declined to be named told reporters, adding that unpaid debts also needed to be cleared.

Kingfisher, which has never made a profit since it started operations in 2005, owes millions of dollars to banks, airports, fuel suppliers and its staff.

Most of its 4,000-odd employees have not been paid since May 2012, which led to an agitation by its pilots and engineers in October.

The airline lost permission to fly after a deadline to renew its suspended licence with the aviation regulator expired at the start of the new year.

Mallya wrote to staff on Wednesday, saying he had submitted a detailed restart plan to the aviation regulator requiring funding of Rs6.5 billion rupees (Dh442 million, $118 million), which would be provided by the airline’s parent UB Group.

He reiterated that there were “discussions with multiple investors”, including Abu Dhabi-based Etihad Airways, to sell a stake in the airline.

In more bad news, India’s service tax department issued a notice last month to the carrier, “impounding” all its aircraft, the Press Trust of India news agency said on Thursday.