That's great that the MAX is Stable even with MCAS turned off. I think we wasted pages on debating what stable is. Without MCAS the MAX is not an unsafe aircraft.
If that is the case, why aren't Boeing simply removing MCAS?
As I wrote which now seems like years ago - while MCAS was needed to meet a reg - sometimes regs need to be looked at and exceptions made in certain cases as they can add too much complexity for very little to no safety benefit(the stick force requirement decreeing that the force must always be increasing and can't plateau).
Two points to this: Firstly, if MCAS was needed to meet a reg, which one do you mean? Secondly, if it was needed to meet a reg, why was it not known before the Lion Air crash? Anything installed in an aircraft in order to fulfil regulatory requirements must be traceable and thus disclosed as part of certification. To my knowledge, Boeing's argument at the time of certification was that MCAS impacts the aircraft's characteristics to such a small extent that noone needs to know about it, even the pilots.
In terms of AOA - The NG has been flying very safely with 2 AOA sensors for decades now - why add unneeded complexity? Let it be. Even with three sensors there are examples of those planes almost going into the ground.
Again, two points: Firstly, as far as I'm aware, the NG only ever flies using one of the two flight computers, alternating between the two available units for each flight. As such, the NG would only ever be using one AOA sensor. Also, the NG never had any flight control system feeding off it - it was purely informational - and thus requires no further complexity. On the MAX, however, a system with the ability to significantly influence the aircraft's flight control was installed that used the AOA as its (only?) input. This requires additional complexity to avoid it acting on a wrong input. On most aircraft with similar systems, the common practice is to use three AOA sensors to be fully immune to the random failure of a single sensor.
Secondly, )'m very interested in what examples you have of aircraft with three sensors almost going to the ground. Can you name them please? The only incident I know of that is directly related to AOA sensors is LH1829
. I'd like to know of more these types of incident.
One of the downsides of making a plane too perfect is Pilot's start assuming that it is perfect and that it can do nothing wrong. Instead of trusting their own training (assuming they had half decent training) when something goes wonky with the flightpath they start analyzing the systems vs just flying the aircraft like they are supposed too.
In my opinion, if we start assuming that aircraft are perfect, then we have already lost before we start. Any system not only can but will fail. If we do not start from that assumption, then we will not make good decisions, both in terms of aircraft design as well as pilot training. The problem with MCAS on the MAX is that it was not included anywhere in pilot training so that when it activated, the pilots could no longer just fly the aircraft like they are supposed to.
Until such time that AI can be perfect and take over the whole flight - I suggest we reexamine how we train commercial pilots and no more 100 hour wonders which end up in an 737 without having any real experience actually flying and dealing with adverse situations.
As mentioned earlier, any system will fail - the same goes for AI. So, I wouldn't put too much hope in that eliminating the need for pilots. We humans have a much greater array of inputs (eyes, ears, nose, sense of balance, experience, intuition) and can apply these to unforseen situations, something any programmed system is incapable of.