New Delhi, Nov. 11 -- Engine maker Pratt & Whitney has assured IndiGo that it intends to replace faulty engines of 40-odd grounded planes of the country's largest airline by end-June 2026, said two persons with knowledge of the development. This move potentially will boost IndiGo's profitability this year and next, depending on the pace of engines replacement, reducing the carrier's reliance on costly leased planes to offset the nearly-10% unused aircraft on its fleet. The airline flies two of three passengers in India. Forty planes with Pratt & Whitney engines are grounded while 60 are flying. "There is an assurance for a staggered improvement in the aircraft on ground situation with a June timeline," said the first person, on the condition of anonymity, as the discussions between the world's second-largest commercial aircraft engine maker and IndiGo are private. The second person, who also wanted to remain unidentified, said some timelines are still under discussion and revision possibilities cannot be ruled out if global supply constraints persist. Emails sent to Pratt & Whitney and IndiGo seeking comment went unanswered. A resolution could help IndiGo's profitability, according to at least one analyst. Gagan Dixit, analyst at Elara Capital said, the refitting of grounded planes by Pratt & Whitney is well-aligned with new airports opening up around cities that originate the most number of air passengers in India. "As new airports in Mumbai (Navi Mumbai) and Delhi (Jewar) open up, this will correspond with IndiGo's planes being ungrounded. It helps the airline with more capacity, return of costly leases, and aids both topline and bottomline growth." The Mumbai-Delhi route accounts for a third of India's air passenger movement. Revenues from putting these planes back in the skies will be much more than penalties Indigo gets from Pratt & Whitney, Dixit said. "While IndiGo is getting some compensation from the engine-maker, amount of which is undisclosed, it is not enough to cover up for revenue losses." Once the replacements are completed, IndiGo will be nearly free of Pratt & Whitney's geared turbine fan (GTF) engines, marking a gradual closure of one of the Gurugram-based airline's longest-running operational challenges. The crisis, which began in mid-2023, stems from a "powder metal contamination" defect in certain Pratt & Whitney GTF engines that could lead to component cracking. The issue has affected airlines worldwide. IndiGo, owned by InterGlobe Aviation Ltd, has leased 333 passenger jets on so-called operational leases, which are expensive as they come loaded with costs such as maintenance and insurance. These include replacements for the grounded planes with Pratt & Whitney engines. Of the remaining planes on its fleet, 14 planes are owned by the airline and 62 on financial lease where maintenance, insurance and others costs are borne by IndiGo. Eight were on so-called damp leases where the lessor provides not just the jets but also pilots, maintenance and insurance. The number of grounded IndiGo aircraft peaked in 2024 at around 70-80 and has since gradually declined....