What Exactly Is Being Fixed On The Boeing 737 MAX?

The Boeing 737 MAX saga has taken on strangely epic proportions for its relatively short existence. Since the plane’s grounding back in March 2019, the recertification process has taken on near Odyssean features. Just as a potential return to the skies has been heralded, another issue seems to have popped up, one after the other, for Boeing to deal with. So what exactly is being fixed?

Boeing 737 MAX
Since the grounding of the MAX, new issues keep presenting themselves. Photo: Getty Images

Safest ever or inherently flawed?

Some say that, because of all the extra tinkering, the MAX, when it does return to service, will be the safest aircraft around. Others say it is a problematic model to begin with, a rushed job that should never have been built with that hardware and to those specifications.

As anyone familiar with commercial aviation is aware, the 737 MAX has been grounded since March 2019, after a faltering software known as the Maneuvering Characteristics Augmentation System (MCAS) caused two fatal crashes in the space of six months.

Boeing 737 MAX
The MCAS was granted extra powers due to aerodynamic issues arising from the larger engines. Photo: Getty Images

Originally a limited AI

The MCAS was initially intended to be an extremely limited function AI software. It was supposed to kick in to course correct the plane in the case of two sensors picking up extreme wind resistance and force. However, then Boeing decided to put larger engines on its 737 to make the old bestseller more competitive in a new market.

A test pilot noticed issues with handling the plane, and Boeing decided to broaden the scope of the MCAS to more routine instances, not just emergencies. It removed the sensor responding to force so that the software would switch on just in hard wind conditions. Boeing also gave the MCAS more control over the plane in such instances, meaning it would function more aggressively.

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The MCAS has been the biggest issue. Photo: Getty Images


We know what happened next. The system malfunctioned, causing the noses of Lion Air flight 610, and Ethiopian Airlines flight 302, to dive repeatedly towards the ground until they crashed. There was a lack of training on how to handle the aggressive AI if it went haywire, which requires multiple and complex interventions. Even with such training, pilots have failed to override the system in simulations.

Obviously, the MCAS has needed a lesson in humility and extensive re-programming. This includes requiring information from both sensors before activating. Furthermore, it will now only activate once, and will not provide more input than the pilots can counteract using only the control column.

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Since submitting the MCAS fix a whole host of other issues have popped up. Photo: Southwest Airlines

Other issues presented themselves

Boeing first submitted the software fix to the Federal Aviation Administration (FAA) in June 2019. While conducting tests on the flight control system, however, the FAA found an additional flaw with one of its microprocessors.

Boeing proceeded to change the MAX’s automated flight control system so that it will take input from both flight control computers at once. This introduces a fail-safe, as they receive input from separate sensors.

Normally, it would only use one computer during one flight and then switch to the other on the next one. This has been the case in the 737 series for decades, but the MAX has different requirements than its predecessors.

Since then, issues have been discovered with an indicator light that would falsely light up, again due to a problem with the flight control computer. Irregularities have also been found with the software that oversees the powering up of the plane.

Furthermore, the company has also run into the dilemma of whether or not it needs to separate wire bundles potentially too close together that help control the tail of the aircraft. And if so, then they most likely need to separate the wires on all the MAXs built to date.

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The 737s flight control computers have the same processing power as a Super Nintendo. Photo: Getty Images

Asking too much of the computers?

An issue not so easily fixed lies deeper at the core of the 737 series. The reliable computers that have made it one of the safest aircraft around (up until the MAX) have the same processing power as a Super Nintendo. That is 16 bits, and its era ended with the 64-bit console, first released in 1996.

This was fine for the needs of aircraft up until a few years ago when Boeing, all of a sudden, asked it to do way more for the MAX than it had for previous models. The aerodynamic issues that arose from the addition of the new larger and heavier engines needed to be fixed with hardware changes.

However, such measures would have required more time, cost, and regulatory proceedings, putting the MAX behind schedule to compete with the Airbus A320neo. And so, Boeing threw software at the problem instead, which became too much for the outdated computer to handle.

Therefore, the question arises if all the software fiddling in the world will ever be enough if it is too sophisticated and complex for the underlying system.

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Will Boeing be able to rebuild trust in the MAX? Photo: Getty Images

Trust issues

Another matter is if people will trust Boeing enough to fly on the MAX, once it is back in the air. Getting on an airplane requires a significant amount of trust in the first place. Even if it is the safest form of transport around, you need to trust (obviously) the pilots, the crew, the maintenance workers – and the aircraft’s manufacturer.

Disturbing internal correspondence was leaked following the two fatal crashes caused by the MCAS. The condescending tone and disregard for safety displayed in those emails may have caused a breach in confidence that will take more to fix than the glitches in the software that keep popping up. Rebuilding that relationship may be more complex even than the recertification has been so far.

What do you think about the MAX? Will she be the safest ride around, or are there fundamental issues that are too difficult to overcome? Let us know your thoughts in the comments.