IndiGo started to induct the A320neos with the GTF Engines in March 2016, and since then has seen multiple troubles with this new technology. Mid-flight engine shutdowns and warnings became common, often causing diversions and a headache for the airline and its passengers. The Indian regulator, DGCA, had to step in and warn the OEM to give top priority to sort out the issues with the aircraft.
IndiGo themselves moved on from the PW GTF engines to award a significant order to the other engine maker for the A320 aircraft family, CFM Engines, whose LEAP engines have been performing more steadily and are also hung on the planes that Air India, Vistara, Akasa and Air India Express fly. The last GTF-powered aircraft with IndiGo was delivered in 2020.
As of September 2023, IndiGo has about 334 aircraft in its fleet, of which GTF Engines power 137. With these earlier known issues, IndiGo has about 45 aircraft grounded across the country awaiting engines from Pratt and Whitney. The airline does not comment on the number of aircraft grounded, so these numbers were aggregated from FlightRadar24 and other aviation data websites.