Whistling sound in cockpit prompts Delhi-Mumbai Vistara flight to return midair

A Delhi-Mumbai flight of Vistara airlines returned midway to Delhi on Monday after a "whistling" sound was heard on the right side of the Boeing 737 aircraft cockpit, a DGCA official said.

The DGCA (Directorate General of Civil Aviation) has ordered a probe into the incident even as no structural deficiency was observed during preliminary ground inspection of the plane, the official said.

Vistara a joint venture of Tata and Singapore Airlines Limited (SIA) confirmed the return of its Mumbai flight UK 951 back to Delhi, saying that the pilot decided to do so after a technical snag was detected shortly after its take-off.

An alternate aircraft was immediately arranged to fly the passengers to their destination, it said. 

Besides Vistara, Tata Group also owns Air India and its low-cost international arm Air India Express and it holds a majority stake in low-cost airline AirAsia India.