A mid-air engine failure forced an IndiGo flight bound for Lucknow to return to Ahmedabad, where it made an emergency landing this morning, an official said. The Airbus A320 Neo plane, which had 186 passengers on board, landed safely, Ahmedabad Airport director Manoj Gangal said. The aircraft, powered by Pratt & Whitney Neo engines, returned to Ahmedabad after being airborne for over 40 minutes, he said.