What is the MCAS system used in the Boeing 737 MAX 8 and why it could be related to the accidents of Lion Air and Ethiopian Airlines

The similarities between the accidents of Lion Air and Ethiopian Airlines drew attention to a stabilization system used in the new Boeing 737 MAX 8 aircraft.

The MCAS control system (System for increasing maneuvering characteristics) is an automated security feature on the 737 MAX 8 designed to automatically connect and make corrections if certain parameters are exceeded in maneuvers of altitude and change of course.

The Lion Air plane, which crashed in October, killing 189 people, including the plane of Ethiopian Airlines, crashed on Sunday and killed 157 people., were equipped with this system.

Both aircraft experienced uneven climbs and descents and fluctuating flight speeds. before crushing Shortly after takeoff.

Despite observing the similarities between the accidents of Lion Air and Ethiopian Airlines, the United States Federal Aviation Administration (FAA) stated that it was too early to draw conclusions.

The MCAS was introduced by Boeing in the 737 Max 8 model because its engines -more heavy and efficient in the use of fuel- they have changed the aerodynamic qualities of the aircraft and could cause the lifting of its end under certain conditions during the manual flight.

"It's a system that optimizes the flight profile and helps pilots keep the aircraft in a position"Appropriate", summarized Michel Merluzeau, aeronautical expert at AirInsight.

This is done by horizontal stabilizers in the tail of the plane which are activated by the flight control computer of the aircraft.

According to Boeing, the MCAS does not control the aircraft during a normal flight, but "improves the behavior of the aircraft" during abnormal situations.

For example, during sharp turns or after takeoff, when an airplane is gaining height with the flaps open at a high loss speed.

According to the flight data, the pilots of the Lion Air flight 610 fought to control the plane, while the MCAS automated system repeatedly pressed the nose of the aircraft during takeoff.

The pilots of the plane Ethiopian Airlines they reported a similar difficulty before the aircraft crashed on the ground shortly after takeoff.

Software update

Lion Air Flight 610 Preliminary Report he blamed a faulty attack angle sensor that activated the MCAS system and automatically forced the tip of the plane down.

Pilots flying in the same plane from Lion Air the day before had managed to bypbad the automated flight control system.

After the accident of Lion Air, Boeing was criticized for failing to adequately inform the pilots of the 737 pilots operating the MCAS. or provide training on the system.

After the accident of Lion Air, Boeing published a newsletter for airlines operating the 737 Max 8, teaching pilots how to replace the MCAS system.

The American aircraft manufacturer issued a statement Monday that It was too early to determine the cause of the crash of Ethiopian Airlines.

Boeing also said it was working on software updates for the MCAS system deployed in the 737 Max fleet.

He badured that there are procedures to "safely handle the unlikely event that erroneous data comes from an angle of attack sensor (AOA)", which is suspected caused the accident of Lion Air.

"The pilot can always override the flight control law (MCAS) by means of an electrical or manual adjustment", claimed the aircraft manufacturer.

More and more countries are barring the use of 737 Max devices. after two fatalities in just five months.

Boeing described his Max series as the best-selling aircraft, with more than 5,000 orders placed to date to approximately 100 customers.

Since the 1970s, when McDonnell Douglas DC-10 had several fatalities, no other new model has been involved in two fatal accidents in such a short time.

(With information from AFP)