India's Director General of Civil Aviation has ordered the immediate grounding of 11 Airbus A320neos fitted with Pratt & Whitney PW1100G engines following recent aborted take-offs and in-flight shutdowns.
The DGCA says that A320neos with engine serial numbers 450 and beyond will be grounded.
These comprise eight IndiGo A320neos and three GoAir aircraft.
The DGCA has also ordered the airlines not to refit the engines even though there are spares in their inventories.
The grounding follows the emergency landing of an IndiGo A320neo in in Ahmedabad on a service from Lucknow on 12 March. The aircraft "experienced [a] technical glitch with its Number 2 engine", says the carrier.
Two similar cases occurred recently, the DGCA notes: a Jammu-bound GoAir A320neo returned to Leh on 24 February and a Kolkata-bound IndiGo A320neo returned to Mumbai on 5 March.
The DGCA has been informed by the European Aviation Safety Agency that it is evaluating "some interim proposals," and will be revising the emergency airworthiness directive "in due course as soon as current affected engines will be modified with a safer interim design".
P&W expects to replace all the affected engines "by early June", adds the DGCA, even though "there is no concrete proposal in place at this stage to address the issue".
The regulator says it "will continue to be in touch with the stakeholders and review the situation in due course as and when the issue is addressed by EASA and P&W".
Flight Fleets Analyzer shows that IndiGo operates 29 A320neos within its fleet of 157 aircraft and has 398 of the type on order. Meanwhile, GoAir operates 13 of the re-engined narrowbody and has 131 on order.