Boeing Issues Software Fix For 737 MAX Aircraft After Two Fatal Crashes

After the crash of two brand new 737 MAX 8 aircraft, Boeing has introduced a software fix designed to make these aircraft safer. Once this fix is approved, it will be presented to 737 MAX customers.

Boeing desperately needs to save the 737 MAX from negative publicity. Photo: Boeing

The Software

Anyone following the news of the Lion Air and Ethiopian Airlines crashes knows two things. Firstly, they involved brand new aircraft. Secondly, the crashes were very similar in nature. After the Lion Air crash, scrutiny was drawn to a system on the 737 MAX called the Maneuvering Characteristics Augmentation System or MCAS for short.

Boeing designed the MCAS on their 737 MAX with the purpose of helping pilots recover from a stall. In theory, the system is a great idea. If sensors detect that the airplane’s angle of attack is too high, the system will automatically pitch the nose downward. However, something went wrong, to disastrous consequence.

Many pilots were seemingly unaware of the MCAS system, so when the angle of attack sensor gave a false reading, they didn’t know why the nose was trimming down. Pilots wrestled against the system as the vertical speed of the aircraft became erratic, with the system winning out in these two tragic cases.

Lion Air pilots wrestled against the system in an effort to save their aircraft. Photo: Boeing

The Fix

The 737 MAX is a big moneymaker for Boeing. It’s their most successful aircraft model to date. With Garuda’s recent cancellation, the floodgates could be opened for many of their customers to abandon the aircraft in favor of rival A320neos.

Recently, Boeing officially introduced new fixes to the 737 MAX software designed to reduce the impact from erratic sensor readings. These fixes come after recent studies Boeing has conducted on the system. Pilots from American Airlines and representatives from Southwest Airlines and United Airlines were involved in some of the testing on improvements to the 737 MAX.

United flies the 737 MAX 9. Photo: Boeing

The changes to be implemented include:

  • The MCAS system will analyze data from two angle of attack sensors. Previously, the system only received data from one of the sensors
  • The new software will have the MCAS disabled if the readings from both sensors disagree by a margin of 5.5° or more.
  • In the cockpit, the flight control display will be modified with an indicator light to alert pilots to different readings from both sensors. This feature was originally an option for airlines, however now Boeing will be installing it on all new 737 MAX for free.

In addition, Boeing has modified their pilot training for the 737 MAX. Pilots will now have to undergo specific training regarding the MCAS system. With greater knowledge of this system, Boeing hopes that 737 MAX pilots will better be able to identify any potential issues with the MCAS system, and avoid another accident.

When will the 737 MAX return to the skies?

Boeing’s software fix is a step in the right direction. However, regulatory agencies, including the FAA, will have to certify the upgrades before it can be sent to customers. Once customers receive the update, they will have to install it and allow time for pilots and the aircraft to undergo additional training and testing.

Boeing would like the worldwide grounding of the 737 MAX to end swiftly. For regulatory approval, this process could take anywhere between a few weeks to a month or more, as agencies will need to rigorously test the improvements.

Boeing’s distinct 737 MAX winglet could soon return to the skies. Photo: Boeing

While some airlines planned out the groundings to last a few months, the 737 MAX could be flying again sooner than anticipated. Once the 737 MAX returns to the sky, however, Boeing will likely have a few more issues to take care of.

We’ll keep you updated here at Simple Flying.

Would you fly the 737 MAX with this software update? Do you trust Boeing’s 737 MAX? Let us know in the comments below!

2 comments
  1. Yaaay, here comes the software update! We’d like to thank Boeing’s leadership, their hard working engineers, and their ties with uncorrupted politicians. This software should save the lives of passengers this time.

  2. 2 sensors is not enough. 3 is the minimum for a reliable solution, that I would trust.
    So no thanks to ever step into a 737 MAX plane.
    Also. Boeing has clearly only tested sunny days scenarios in their old software. This is beyond what I can forgive. It is totally irresponsible and those people at Boeing have those lives on their hands.

    I have worked with avionics software and sadly it seems that many people in this industry have a “good enough to ship” attitude if you can just get the paperwork in order. Then it does not matter that the actual code is a mess without any unit tests or module tests and generally in a much poorer quality than an average website.

    The whole standards system is flawed as it grown out of a physical world where the idea is that if you only make changes to a subsystem, then only that needs to be tested again.
    The premise does not hold for software – at all. Almost any change to the software will require you to test it completely again. SW components are reused many places in the system and interact with each other in way nobody can predict a 100%. It’s like when you change a bolt on the wings, but for software this would be like changing all the bolts on the entire plane. if people does not understand this, then we will see many more planes dropping in the future.

    Part of the solution at least is to require 100% testing of all the software for any change. This is only practically feasible with the vast majority of the tests being completely automatic. But this is what people outside the “embedded” software world has been doing for a long time, so it’s totally doable – but requires that you design the system from the ground up with this mindset.

    -Martin

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