DGCA directs checking of all Boeing aircraft fuel switch locks
What's the story
The Directorate General of Civil Aviation (DGCA) has ordered airlines operating most Boeing aircraft variants to check the locking mechanism of fuel control switches by July 21. The directive comes after preliminary findings in the Air India Boeing 787 crash investigation revealed that the fuel control switches were moved to the "cutoff" position just before impact, cutting off fuel supply to both engines.
International action
Airlines worldwide are inspecting fuel switch locking mechanisms
Apart from India, airlines around the world have started inspecting the fuel switch locking mechanisms on Boeing 787 aircraft. Etihad Airways has already asked their engineers to check these locks, and Singapore Airlines is also reportedly following suit. This comes despite assurances from the Federal Aviation Administration (FAA) and Boeing that the fuel switch locks are safe.
Investigation findings
Confusion led to loss of engine thrust
The preliminary report of the crash investigation by India's Aircraft Accident Investigation Bureau revealed that both pilots were confused over the change to the switch setting. This confusion led to a loss of engine thrust shortly after takeoff. The fuel cut-off switches in modern aircraft like the Boeing 787 are located below the thrust lever and have safeguards such as metal locks and guards to prevent accidental shutoff.
Safety bulletin
Focus on operation of fuel control switches by pilots
The report also mentions that investigators are focusing on the operation of fuel control switches by pilots. It further notes that the FAA had sent an information bulletin in 2018 about possible disengagement of the fuel control switch locking feature. However, Air India did not carry out suggested inspections, as they were "advisory and not mandatory." Air India had changed the switches when replacing the throttle control module in 2019 and 2023.
Maintenance practices
Air India had changed switches in 2 instances
The fuel switch has two positions: 'RUN' and 'CUT OFF,' which are used to start or stop engines. According to the report, once the aircraft reached its maximum recorded speed, "Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec." The switches subsequently returned to the "RUN" position, and the engines appeared to be building power, but "one of the pilots transmitted 'MAYDAY MAYDAY MAYDAY.'"