Emergencies are very often situations in which the plane is operating outside of normal parameters or even outside of specified parameters, e.g. a sensor failure or damage to the aircraft. In those situations software can not reliably control the plane and should return control to the crew.

The nature of emergencies themselve make dealing with them in software near impossible. How do you write software for a condition you can not anticipate? How would you test it? How can you make sure that it is not misdiagnosing a situation and making the problem worse?

The 737max disaster should be enough to demonstrate how dangerous misbehaving software in a plane can be.

Human airline pilot here, I'm not sure where you're getting this from:

> Many private planes with modern avionics now have an auto-level button on the AP that very reliably recovers from a dive or other unusual attitudes. Airlines typically don't and it's clear that the simple (and very easy to program) button could have saved many lives.

Every modern jet since the early 90s has this. In every family of Airbus you can press the 'ALT' push-button or pull on the V/S knob. Both will level off the aircraft immediately (with slightly different follow-on characteristics).

Edit: to add more context, this works in unusual situations like dives and high-nose attitudes as well. The only difference is the inertia of a modern jet means the leveling off takes a bit longer.

Is pressing the button now taught/expected as the correct way to recover from unusual attitudes, and does it also handle leveling the wings?

It used to be 'level the wings, pull the nose.' The issue is even expert ATPs often perform the wrong action initially, making the problem worse.

It won't auto-level the wings for you in an airbus, however unless you're in an unusual configuration in alternate or direct laws (requiring a significant series of failures), the bank angle is limited by the aircraft anyway (whether you're on AP or not). For reference, in my 10 years of operating Airbus aircraft I have seen alternate law just once, we train it in the sim regularly but it's not a common occurrence.

Pressing ALT is taught as the correct thing when you're not completely sure what to do but for a fully unusual attitude (e.g. really nose-high or nose-low, or an acute bank angle) then currently the procedure is to handle it manually. To be honest, to get a large aircraft into that situation requires a pilot to screw it up badly in the first place, the AP won't get you there (well it might but hasn't happened yet).

A couple of years ago most airlines started training a more verbose method of recovery (disengage, push/pull, roll, thrust, stabilise - is the mantra) in response to studies conducted by Boeing and Airbus. Before airlines I used to compete in and teach advanced aerobatics so I'm not completely happy with that procedure (e.g. why push/pull first if you have huge bank on, only going to make things worse) but it's what the industry is pushing right now.

Overall though I think the bigger issues with pilot error are not things like unusual attitudes, yes they do happen from time to time but far more incidents occur from unstable approaches and silly inputs during takeoff. Hence why most changes in regulation right now are in those areas.