Budget carrier IndiGo has been dogged by a host of technical issues with the Pratt & Whitney engines fitted on its Airbus A320 Neo. The airlines has now taken measures to prevent mid-flight engine stalling.

It put a cap on its take-off thrust after the Directorate General of Civil Aviation found that only Indigo’s planes were susceptible to engine stalling. GoAir, which also uses Airbus A320 Neo with the same engine, has no such problem.

The airline watchdog found that Indigo pilots were resorting to maximum thrust of the engine right after takeoff, while GoAir was using the alt-climb approach that applies less thrust. The maximum thrust method helps save on fuel but wears down the engine and this could lead to mid-air stalling.

IndiGo has now told its pilots of A320 Neo to attain full thrust only after reaching a height of 31,000 feet, while those flying the bigger A321 Neo need to climb a further 2,000 feet before applying maximum power.

India’s leading airline by market share has suffered 13 engine shutdowns related to low-pressure turbines during climbs, this year. The airline is the only one to have encountered turbine failures. IndiGo operates about 100 planes fitted with Pratt & Whitney engines.

Airlines regulators also told IndiGo that all such aircraft in its fleet must have modified Pratt & Whitney engines by January 31 next year “at all costs.” They have threatened to ground the entire Indigo fleet if it fails to meet the deadline.

IndiGo CEO Ronojoy Dutta has expressed reservations about the deadline for changing the entire fleet.

In June, IndiGo had shifted away from Pratt & Whitney engines and placed an order to CFM International Inc, but those deliveries are yet to start.

The budget carrier is focussed on growing its international routes and its fleet includes a long-range version of the single-aisle A320 Neo family, A321 XLR. Indigo wants to fly to Istanbul and London.

The airline had last month signed a codeshare agreement with Qatar Airways.

Apart from the technical woes, the airline is also facing turbulence in its boardroom, with its two promoters, Rakesh Gangwal and Rahul Bhatia, at loggerheads. Gangwal had alleged that he was being sidelined and had even approached the stock market regulator, Securities and Exchange Board of India, in this regard.

Although the two founders enjoy almost equal stakes in the airline, Bhatia wields much greater control over the board and management. His holding company Inter-Globe Enterprises (IGE) has the right to appoint key managerial personnel, including the chairman, managing director, CEO and president. It also has the right to nominate three non-independent directors, one of whom will be non-retiring.