India, Feb. 5 -- Air India on Thursday said it is investigating whether its crew followed all required compliance procedures after a Boeing aircraft took off from London despite a possible fuel-switch defect, before being grounded later in India.

Britain has given Air India a week to submit a complete response, warning that failure to do so could invite regulatory action against the airline and its fleet of 33 Boeing 787 aircraft.

Authorities said pilots in London noticed that a fuel control switch did not remain latched in the "run" position during two attempts, though it appeared stable on a third.

The crew subsequently decided to operate the flight to India, where the pilot reported a possible "defect" after landing, leading to the ...