The United Kingdom’s Civil Aviation Authority (CAA) has sought an explanation from Air India over a fuel control switch malfunction involving a Boeing 787 Dreamliner that operated a London–India flight and was later grounded for safety checks on arrival.

In a letter to the airline, the CAA questioned why the aircraft was permitted to take off from London if a malfunction in the fuel control switch (FCS) was suspected. The British regulator has warned that failure to provide a complete and satisfactory response within a week could invite regulatory action against Air India and its Boeing 787 operations.

According to India’s civil aviation regulator, the fuel control switch failed to lock properly in the ‘run’ position twice during engine start procedures at London’s Heathrow Airport. The issue was reportedly resolved on the third attempt, after which the pilot decided to proceed with the flight to India. Subsequent inspections, however, found the switches to be in satisfactory condition.

Air India has maintained that a re-examination of the fuel switch revealed no defect. The airline has assured regulators that it will submit a detailed response to the CAA, including maintenance records, a root cause analysis of the incident and measures being taken to prevent a recurrence.

The CAA has also sought comprehensive information on the aircraft’s maintenance history and the airline’s internal assessment of the malfunction. Air India stated that it has inspected fuel control switches across all 33 Boeing 787 aircraft in its fleet and found no issues. Of these, 28 aircraft are currently operational.

The aircraft, carrying around 200 passengers, landed in Bengaluru on Sunday and was grounded immediately for precautionary checks after the pilot reported a possible fuel control switch malfunction during landing.