Chennai, Aug 28 (PTI): A Delhi-bound Jet Airways flight carrying 165 passengers and seven crew members onboard was forced to return today after the sudden deployment of oxygen masks in two rows of the aircraft.

Aviation regulator Directorate General of Civil Aviation (DGCA) has initiated a probe into the incident, which happened this morning, sources said.

The probe would look into the reasons for the sudden deployment of the oxygen masks on Jet Airways flight 9W-820, which could also be because of some maintenance issue, they said.

The aircraft remained airborne for almost twenty minutes before landing back at the Chennai airport at around 10:30 am, they said.

"The Oxygen masks came down from the ceiling panel above the seats in the two rows of the aircraft after some 20 minutes of the take off, forcing the pilot to return the plane back to Chennai," the sources said.

Jet Airways, in a statement said that the flight came back to Chennai without completing its journey due to accidental deployment of the oxygen masks.

"Flight 9W 820 from Chennai to Delhi made an air turn back due to accidental deployment of oxygen masks in two rows of seats and landed in Chennai," the airline said.

The aircraft was changed and the flight departed for its destination later on, the statement added.

Last month also, Jet Airways Delhi-Leh flight had come across a similar issue when oxygen masks were automatically deployed during the landing due to the low-cabin pressure, leading to the grounding of the plane.