It makes sense that very minor differences don't require extra training if the differences have no meaningful impact on cockpit design or flight characteristics. But in this case, flight characteristics were clearly different, and MCAS was supposed to compensate for those differences.
I don't know how they measure such differences, but you'd think that different engines, different aerodynamics, and a new control system to compensate for those differences, are enough to warrant a new type certification.
They should really have type certification diffs. If 90% of the airplane is the same as the previous version, the manufacturer should expect a type certification procedure that costs about 10% of a fully new design and pilots should gain the new type rating with about 10% of the effort and hours of what would be required for a completely new plane.
It sounds really cumbersome to have it either-or way, making it difficult to develop planes too much incrementally and keeping it very costly to start from scratch with a completely new design.
well, yes, exactly, MCAS was supposed to compensate for these differences, to make sure that the flight characteristics are close enough to not require additional training. But tragically, what was supposed to be part of the solution turned out to be part of the problem...
I don't know how they measure such differences, but you'd think that different engines, different aerodynamics, and a new control system to compensate for those differences, are enough to warrant a new type certification.