Indian low-cost carrier IndiGo has again temporarily grounded some Airbus A320neos as it awaits spare Pratt & Whitney PW1100G engines.
The carrier's parent company InterGlobe Aviation states in a stock exchange disclosure that "as part of our normal maintenance schedule, a few A320neos have been taken out of service."
"We are currently waiting for spare engines from Pratt and Whitney, for which the release process has already been initiated by them. These aircraft are expected to be back in service in the second half of August, 2018," it adds.
IndiGo would not clarify many aircraft are out-of-service when contacted by FlightGlobal. Local media reports say that five of the A320neos are grounded at present.
Flight Fleets Analyzer shows that IndiGo operates 39 A320neos within its fleet of 171 A320s, with a further 391 of the type on order.
The carrier has had to ground a number of A320neos over the past two years due to issues with the PW1100G engines. In March, India's Director General of Civil Aviation ordered the grounding of eight IndiGo A320s, as well as three from GoAir, following aborted take-offs and in-flight shutdowns.
A knife edge seal issue was discovered in January which was traced to a design change introduced last year. That was intended to rectify earlier problems with the engine, but made it worse.
P&W chief executive Bob Leduc previously said the engine’s original knife edge seal was delivered with a design flaw that required an inspection after a certain interval of flight hours.
P&W has since resumed shipments of PW1100Gs to Airbus with a previous design of a knife edge seal that does not have the flaw.
The engine manufacturer told FlightGlobal last month that it expects to rectify issues with the knife edge seals on the in-service fleet of PW1100G geared turbofan engines by the middle of 2019.