As far as I'm aware, it would glide as well as any other 737 if both engines were cut. It merely had a slightly lower maximum nose-up because of the increased engine thrust or something like that.
It wasn't the engine thrust. There were a bunch of subtle design changes because newer, fuel efficient engines are much larger than the style of engine when the 737 was first designed. Unlike the competing A320, the 737 didn't have the necessary clearance under the wing to fit the new engines.
They had to make a bunch of tweaks like moving the engine higher up, further forward, tweak the wings etc. to make it fit with the necessary ground clearance. These subtle differences added up so they added MCAS to make it handle closer to the original design.
But instead they wanted to handle like something it wasn't and then made buggy fix for it to do so.
This had two problems. Firstly, this flight characteristic (more AoA gives less stick pressure) is considered risky, because it can trick pilots into thinking the AoA is decreasing. Secondly, and apparently more importantly to Boeing and American Airlines, this meant that pilots certified to fly the old 737 would need to go through new training. This new training was required because of a significant change in flight characteristics and would be very expensive to airlines.
So Boeing created MCAS, and tried their best to hide the change so no one would question whether new training might be required. If I recall correctly lion air (the airline of the second MAX crash) had actually asked Boeing if they should do some new simulator training for the 737 max in an e-mail and had been ridiculed for even asking that.
There’s a similar failure mode in pre-MAX 737s called “runaway trim”. The giant trim wheels on the center pedestal spin in a loud and attention-getting fashion. The fix? Pull the breaker on the overhead panel.
The MAX does not have a stick pusher. MCAS works on the position (trim) of the stabilizer. The elevator feel system (which the NGs have as well) works by creating additional resistance at the yoke (which is hydraulically assisted). Neither are stick pushers.
> There’s a similar failure mode in pre-MAX 737s called “runaway trim”.
That's a thing that can happen on any plane with a similar horizontal stabilizer setup. I'm sure even a plane with a flying stabilizer (e.g. L-1011) has similar failure modes.
> The giant trim wheels on the center pedestal spin in a loud and attention-getting fashion.
The "giant" trim wheels were reduced in size on the NG (and MAX?) reducing their leverage.
> The fix? Pull the breaker on the overhead panel.
There are two switches (whose function was subtly changed with the MAX) that control the trim motors and they're located behind/below the thrust levers.
The design goal for the software was to make it fly like other 737s. The software did not actually do that, but did "something" that inspectors allowed was just enough different from without to certify. And, in case of equipment failure, or various other circumstances, the software failed completely, because it was just really badly designed. If you knew about the system, you could turn it off in case of trouble, and then the plane would fly fine, just not enough like a real 737 that you could completely ignore the difference.
Then they made it hard to know that the system was there. People who knew how to turn it off could prevent disaster.
Thing is though the pilots of the second MAX crash took all the right steps. Just too slow.
There was like 10 seconds to turn off mcas, after that a crash was inevitable.