Peter wrote:
If not, how is the protection available unless flying on autopilot?
If like the PA46, the autopilot is always there for ESP and envelope protection. Of course no auto throttles. But it will lower nose to prevent a stall.
Is it a “stick override” i.e. the pitch servo is always engaged?
I assume it is more like a stick pusher. But yes the autopilot is always engaged and the servos will act to protect the pilot if the computer detects an out of envelope condition.
OK, but without auto throttle coupled into GPWS (even an Airbus doesn’t have that), you can still kill yourself simply by reducing power.
So, the scenarios where this system will save your life are quite narrow – because the only time a stall will kill you is when you hit the ground as a result, and there is no plausible scenario where this should happen at altitude, with a live pilot at the controls.
Traditionally, most stall/spin fatals in GA are on the base to final turn, or some other mismanaged operation during landing.
Peter wrote:
If not, how is the protection available unless flying on autopilot?
Is there any other way or flying? 400ft A/P ON 
DMEarc wrote:
On newer model Cirruses (2010+) a stall should be relegated to the history books due to ESP and Underspeed Protection. ‘Pros’ will put down these technologies but they are the future (and wonderful).
Not that I want to knock technology, I enjoy electronic aids even on motorcycles (cornering ABS is great; not that one should suddenly willy nilly brake in corners, but it sure is nice to have in the toolbox for emergencies). People still manage to stall airliners. The protection can always pack up. And in some cases, you will fly into terrain nicely instead of spiraling into it.
Peter wrote:
Traditionally, most stall/spin fatals in GA are on the base to final turn, or some other mismanaged operation during landing.
I think it should help even there. That situation is dangerous because you’re so low you won’t be able to recover. This will ensure a plane stays controllable. If you take the loss of control element out of it, it’s just a question of recognizing whether you’ll make it to the runway. And it’s not limited to pitch. It should just monitor flight parameters and if you get outside the envelope, it uses servos to correct attitude. I don’t see why a servo would have to be engaged all the time.
PS:
Peter wrote:
and there is no plausible scenario where this should happen at altitude, with a live pilot at the controls.
You do remember AF447, don’t you? Altitude just buys you time. And it sure is nice if you can avoid spin or spiral. If you let it develop too far, you might not be able to recover.
AF447 happened due to a loss of airspeed coupled with two pilots who didn’t understand the aircraft systems (they were just button pushers). The SR22 envelope protection will have the same problem if you lose airspeed (e.g. simply forgot to turn on pitot heat) and the pilot is not, shall we say, performing sensible actions.
It’s a good thing for sure, but the statement
a stall should be relegated to the history books due to ESP and Underspeed Protection. ‘Pros’ will put down these technologies but they are the future (and wonderful).
is over-selling it, IMHO. And I am not a “pro”
Peter wrote:
The SR22 envelope protection will have the same problem if you lose airspeed
Not necessarily. It shouldn’t be too hard to have the system revert to flying fixed pitch and power if the airspeed suddenly packs up and GPS speed remains constant. After all if pitot speed suddenly goes to zero with constant attitude what chances are there for it to be a valid indication other than hitting a very solid obstacle.
True, but you don’t have auto throttle here so no control over power. Even the Airbus would not, upon getting unreliable airspeed, apply 2.5 degrees up pitch and 80% N1 (or whatever).
