Boeing is planning a hefty software update of its autopilot systems after two 737 MAX crashes that led to grounded airplanes globally. The aviation giant began developing a flight control software update for the 737 MAX following the deadly Lion Air crash in late 2018 aimed at increasing the safety of what they consider an already extremely safe aircraft.
The software update includes changes to flight control systems, pilot displays, operation manuals and crew training. What's noteworthy is that Boeing is apparently releasing the update quicker and with more urgency following the Ethiopian Airlines crash this week.
Although no official reports have been released, it's believed that the Lion Air crash stemmed from a feature called the Maneuvering Characteristics Augmentation System (MCAS). The 737 MAX planes were built with larger, fuel efficient engines that had to be mounted in a different spot on the plane.
The new mounting position changed the plane's center of gravity, potentially causing the plane's nose to pull upward during flight and stall the engine. The MCAS system is meant to automatically correct the upward pull by pointing the nose downward.
But in the Lion Air crash, it's believed that the MCAS system may have kicked on erroneously from a faulty sensor reading and forced the plane into a nose dive, with the pilots either unaware of what was happening or unable to correct it. Boeing contends that pilots have always had the ability to override the MCAS system if necessary.
From the Boeing press release:
A pitch augmentation control law (MCAS) was implemented on the 737 MAX to improve aircraft handling characteristics and decrease pitch-up tendency at elevated angles of attack. It was put through flight testing as part of the certification process prior to the airplane entering service. MCAS does not control the airplane in normal flight; it improves the behavior of the airplane in a non-normal part of the operating envelope.
Boeing's 737 MAX Flight Crew Operations Manual (FCOM) already outlines an existing procedure to safely handle the unlikely event of erroneous data coming from an angle of attack (AOA) sensor. The pilot will always be able to override the flight control law using electric trim or manual trim. In addition, it can be controlled through the use of the existing runaway stabilizer procedure as reinforced in the Operations Manual Bulletin (OMB) issued on Nov. 6, 2018.
Boeing plans to have the software update released by April.