NEW DELHI : India’s aviation regulator on Sunday directed the country’s largest airline, IndiGo, to stop flying Airbus A320neo planes powered by Pratt & Whitney (P&W) 1100 series engines that have been in operation for more than 3,000 hours, a top official of the agency said. The airline has a fortnight to comply with the instruction.

The directorate general of civil aviation (DGCA) issued the directive after three separate cases of engine shutdown on such aircraft on 24, 25 and 26 October, the official said on condition of anonymity. A team of DGCA officials visited IndiGo’s offices earlier in the day to review the airline’s maintenance and safety data.

“These shutdowns were commanded shutdowns," the DGCA official said. As many as 16 IndiGo aircraft are expected to be affected by the order, he said.

“We are continuing to work with the authorities and will take necessary actions, as required, going forward," an IndiGo spokesperson said.

Airlines operating A320neo or A321neo aircraft powered by P&W engines have faced several engine problems. Major ones involve combustion chamber distress, low pressure turbine and gear box failures, and engine vibration. Problems such as combustion chamber distress have been addressed and P&W is working on mitigation measures to resolve the rest. Redesigned and more durable LPT stage 3 blades are being incorporated to resolve problems related to LPT failure, while a redesigned piston seal in the high pressure compressor will be used to address transient vibration.

The order means that IndiGo will have to stop flying these planes or use different engines.

IndiGo had a fleet of 245 aircraft comprising 89 A320neo, 129 A320ceo, six A321neo and 21 ATR planes as of 30 September, according to a recent company presentation to investors and analysts. Of this, 216 aircraft are on operating lease, while the rest are either on finance lease or owned by the airline.

At present, two Indian airlines, IndiGo and GoAir, operate A320neo and A321neo aircraft powered by P&W engines.