Maltese investigators have confirmed they are probing the in-flight engine shutdown involving a Malta Air Boeing 737 Max 8-200 after a sun visor detached from a cockpit window.
But preliminary findings from the incident, which occurred on 8 December last year, give only a few additional details on the circumstances.
The aircraft (9H-VUE) had been climbing through 8,000ft en route from Krakow to Bergamo, states the Bureau of Air Accident Investigation in a 12 January update.
It says there was a “detachment” of the sun visor from the R1 window – the main cockpit window in front of the first officer’s seat.
This visor “subsequently struck the engine start lever” for the right-hand CFM International Leap-1B powerplant, it adds.
The 737 Max’s engine-start switches are located immediately behind the thrust levers.
In late 2018 a US FAA bulletin – also distributed by the European Union Aviation Safety Agency – pointed out that some 737 operators had these switches installed without a locking feature engaged. This locking feature is designed to prevent inadvertent operation by requiring the pilot to lift the switch in order to move it.
“Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown,” the bulletin says.
The Maltese inquiry has not stated whether the aircraft involved in the incident – an airframe manufactured in 2021 – had a functioning locking system.
But it states that, following the shutdown, the right-hand engine was “successfully restarted” and the jet proceeded to its destination. There were no injuries among the 193 occupants.
While the event took place in Polish airspace, the country’s investigation authority PKBWL “elected not to investigate” and its Maltese counterpart, as the state of registry, assumed responsibility for the inquiry.
