An IndiGo flight to Calcutta had to return to Ahmedabad, from where it had taken off, after the pilot detected a snag in the engine on Friday morning, airport sources said.

The Airbus A320 Neo aircraft, which operates on Pratt and Whitney engines, developed vibrations.

“During the flight, the pilot momentarily observed a caution message and followed the laid-down Standard Operating Procedures. Taking a precautionary measure, the pilot landed back at the Ahmedabad airport. The aircraft was back in operation after inspection,” IndiGo said in statement.

IndiGo’s A320Neo aircraft had witnessed several snags in their Pratt and Whitney engines, prompting the Directorate General of Civil Aviation to ask the airline to replace 135 engines by January 31. The deadline was extended to May 31.