An A320 neo aircraft of IndiGo experienced engine issues on Sunday, forcing the airline to ground the plane at the airport here, industry sources said. IndiGo, the country's largest airline, has been grappling with issues related to Pratt & Whitney engines powering its A320 neo planes. In the last few weeks, at least five of its aircraft have experienced engine glitches. "An IndiGo flight 6E-6616 operating from Kolkata to Delhi on June 17 was held at the Delhi airport for maintenance after our pilot observed a snag on arrival," an airline spokesperson said. Another aircraft was provided immediately to avoid any disruption or customer inconvenience, the spokesperson said but did not provide an update about the status of the grounded plane. Sources said there were oil chip issues with the plane's engine due to which it was grounded on Sunday. Details about the number of people on board the Kolkata-Delhi flight could not be immediately ascertained. In the 2017 June quarter, IndiGo grounded nine A320 neo planes due to engine issues. The grounding had also resulted in IndiGo cancelling 84 flights on a particular day last year. Then again between February and March this year, 14 planes - 11 of IndiGo and three of Go Air - were taken out of operations due to the same engine issues on the directions of the aviation regulator after a series of mid air shut downs were reported by the two carriers. These A320 neo aircraft are powered by P&W engines.