Boeing 737 MAX 8: MCAS, the software in sight after the tragedy of Ethiopian Airlines

Could a software be one of the reasons for two aerial tragedies that occurred with the same model of aircraft in a few months? The answer is still in the air, but some people mix it as a possible explanation.

In less than five months,
Two Boeing 737 MAX 8 aircraft resulted in fatal accidents: one flight in October for Lion Air and another flight for Ethiopian Airlines on Sunday.

The authorities are investigating the causes, but the similarity between the two incidents and the "technical failures" of the first have placed the aircraft software at the center of media attention. In both cases, the plane lost altitude shortly after takeoff, hitting the ground a few minutes later, leaving no survivors.

In addition, it is known that the flight of Lion Air had suffered "technical problems" one day before the accident, according to a record of flight recording to which the BBC would have had access at the end of the month. 39; October.

However, the
The Federal Aviation Administration (FAA), the regulator of the sector in the United States, considers that the aircraft is "safe" but asked

Boeing

some changes in the design that have to do with the software, that the firm promises to implement "in April so late".

The US agency said on its Twitter account that it would take the necessary action if it discovered a defect in the plane.

"But the FAA pointed out that the investigation was at an early stage, that it should badyze data that it does not have yet and that it would act from a process that will undoubtedly take time, "says Peter Bowes, BBC correspondent in North America.

Meanwhile, speculation continues to rise.

Software "improvement"

The Boeing 737 MAX 8 is an updated version of the 737 used commercially since just 2017. One of the differences with the previous model is that the sensor says "angle of attack" and the software connected to it works differently.

The flight control software is a system called MCAS (Maneuvering Increasing System). It was developed by Boeing specifically for the 737 MAX 8 and MAX 9.

Boeing says that software "does not control the aircraft during normal flights", but "improves part of its behavior in non-normal operating conditions"

Boeing stated that the software "does not control the aircraft during normal flights", but "improves part of its behavior in non-normal operating conditions".

He also points out that the MCAS has been implemented on aircraft to improve their maneuverability and their tendency to lean under high attack angles.

But Indonesian accident investigators have discovered that the sensor on which the aircraft software could have activated an "anti-pinch" system, thus canceling manual controls. It could have tilted the nose of the plane to the ground.

In addition, according to a government database on aviation incidents (to which the newspaper had access)

The New York Times

), at least two pilots who used Boeing 737 MAX 8 aircraft on US routes expressed concerns in November about how the nose of the aircraft suddenly tilted after the activation of the automatic system.

In both cases, the pilots say they managed to regain control of the aircraft after disabling the autopilot. One of the pilots says that the descent began two or three seconds after having activated it.

The problems faced by these pilots would be similar to those who led the fatal flight of Lion Air to Indonesia last October.

In an official document, two American pilots reported having encountered problems similar to those caused by the Indonesian flight.

On Monday, March 11, a few hours after the accident in Ethiopia, Boeing posted on its website a statement in which he announced that he was working on an "improvement" of this software.

On Monday, March 11, a few hours after the accident in Ethiopia, Boeing posted on its website a statement in which he announced that he was working on an "improvement" of this software. In the text, there is hardly any mention of the tragedy of Ethiopian Airlines, but it links the "update" of the software to the crash of Lion Air six months ago.

"Boeing has been working closely with the FAA on the development, planning and certification of the software enhancement and will be applied to the 737 MAX fleet in the coming weeks." The update also incorporates comments received. of our customers, "said the company. company.

Possible challenge

The company says its software update is designed to "make a safe ship even safer." But some doubt that the ship is as safe as Boeing says.

"It is too early to speculate that we still do not know how much the crash of Ethiopian Airlines is linked to that of Lion Air," said Marc Szepan, an academic at Said Business School. , at the BBC of Oxford University. , United Kingdom, who worked as a manager for the German airline Lufthansa.

The convictions related to the accident of Lion Air have triggered alarms stating that it is a technical failure.

"If that's the case – and that's an excellent badumption – and that it turns out that it was exactly the same main cause and it had to do with MCAS, then Boeing will have an even bigger challenge to solve. "

Szepan says software "is at the heart of aircraft certification and can not be changed easily."

A dozen countries – including China, Australia, the United Kingdom and Singapore – and more than a dozen airlines – such as Aeromexico and Aerolineas Argentinas – have pulled this model out of the service. Szepan said it was "extraordinarily rare" to place a new model of ground plane.

"The last time we saw anything like this, it was in 2013, when the FAA withdrew another Boeing, the 787, because of a battery problem."

Szepan notes that the main cause of the accident in Ethiopia is still unknown, but warns that "from a reputation point of view, Boeing must be very careful".

The Boeing 737 MAX 8 is the aircraft that has the fastest selling business during its history.

The security crisis of this model could compromise the delivery of nearly 4,700 orders already approved.