[toufka]

I think (please correct me if I’m wrong), the plane’s “type” is fixed, and pilots have certifications for that “type”. So theoretically the plane is simialar enough to not require completely new training if a pilot is certified to the type - this new 737 Max is grandfathered into the 737 “type”. If it were different enough, then it would be a new type. If the plane is a new type, pilots, and likely all sorts of other things, mist be retrained, and reissued.

So there’s an incentive to not just make the type backwards compatible to keep the common “type”, but also not introduce too many new features that might bring into question the grandfathered training.

This 737 Max added this new “safety feature” without telling the pilots (because it’s the “same type”). And that feature seems to have an unfortunate interaction with other systems in some circumstances.