Boeing has rolled out a series of software updates and fixes to its automated flight control system on board its new 737 Max 8 model, following two fatal crashes involving the aircraft in the past five months.
The American aerospace manufacturer has been “under pressure from crash victims’ families, airlines, lawmakers in Washington and regulators around the world” to prove that the 737 Max 8 is safe, after experts suggested that a flaw in the aircraft’s automated flight system was responsible for the high-profile air disasters.
Almost 350 lives were lost in the two crashes, the first of which was a Lion Air 737 Max which was lost off the coast of Indonesia shortly after take-off in October. On March 10 an Ethiopian Airlines 737 Max crashed minutes after departure from Addis Ababa. Boeing has grounded all 371 planes in the 737 Max fleet, after several countries, including the UK, barred the model from their airspace, The Daily Telegraph reports.
The new fix is understood to focus on the behaviour of an anti-stall system known as the Maneuvering Characteristics Augmentation System (MCAS). This system is designed to automatically bring the nose of the aircraft down if the plane’s Angle of Attack (AOA) sensors detect that the plane is pitched too high, thus preventing a potentially catastrophic stall in mid-air.
However, in both crashes, investigators have speculated that the aircraft’s Angle of Attack (AOA) sensor had fed faulty information to the MCAS, causing the plane’s nose to automatically pitch down despite flying level. Both aircraft crashed after a period of fluctuating altitude as the pilots struggled to regain control of the aircraft’s pitch.
According to ABC News, Boeing has issued a software update that changes the function of MCAS in two significant ways. First, the aircraft manufacturer announced that if the two AOA sensors on the plane offer “widely different readings”, MCAS will deem it a faulty reading and will not activate a pitch-down manoeuvre.
Secondly, the firm added that if a scenario occurs in which the MCAS system is triggered, it will now perform the automated pitch-down only once, allowing the pilots to take control of the plane and negating the possibility of a faulty AOA reading causing the plane to continuously fight against pilot inputs.
However, Boeing is still facing questions from lawmakers over allegations that the firm did not provide adequate training for pilots, and that it is charging airlines extra for “critical” safety features.
Two safety features known as the AOA indicator and the AOA disagree light were not included in the aircraft by Boeing as standard safety features, but were available for an extra charge. The indicator displays the readings of the two sensors and the disagree light activates if those sensors do not agree – information that would have alerted the pilots of the Lion Air and Ethiopian Airlines planes of a faulty AOA reading.
The firm now says that, along with the software updates, the AOA disagree light will come as standard on future models, but it will continue to charge for the AOA indicator.
An investigation of the Lion Air crash in Indonesia revealed that pilots of the 737 Max 8 did not have sufficient information about MCAS. Engadget reports that the aircraft maker has “also produced a new PC-based training program to help pilots better understand MCAS and how to react when the technology is in use”.
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