To understand Boeing’s challenge, consider if you were to build a house with 2000 sq. ft. You spec an air conditioner and heater out for it and run all of the ducts and everything is perfectly working as designed. Now you want to add a room. So you add a 500 sq. ft. room. you split a nearby duct and feed the new room. But your HVAC system is not designed for 2500 sq. ft. and the ducts are not run from your HVAC unit directly to the new room. So now you have a consequence of having diminished the HVAC effectiveness in the existing areas, and also in the new area. To fix the problem, you develop fancy software to control electronic louvers that route air to where it’s needed so that you can prevent hot/cold spots. Now you’ve introduced something else that, if it breaks, can jeopardize the effectiveness of your entire HVAC system. At the end of the day, you have compromised the initial design in a way that can only truly be corrected with a completely new design. Anything but, just adds complexity (more things that can break).

Back to the 737 issues – no matter what Boeing does to fix the 737 Maxes, and even if they are successful in their quest, at the end of the day, they’ve added complexity which reflexively makes their modified 737 Max design inferior to a new design/model. The introduction of and critical dependence on the MCAS software is a byproduct of their modification to a pre-established design. Put simply, MCAS is yet another potential point of failure of the entire aircraft. We want to minimize potential points of failure, not add to them. MCAS would never be a critical feature of a new design, and this is why I believe that Boeing is going to eventually need to discontinue production of the 737 max produce an entirely new plane.