Really? I didn't know that Boeing had envelope protection 30 years ago. I thought this was Airbus world.
My 30 year old Boeing is envelope protected provided the autopilot and autothrottle are engaged it won,t fly below the alpha floor or pass limiting speeds,vertical speed mode however can get into a lot of trouble as has been demonstrated in past incidents.For light aircraft a simple heading hold on a heading bug and altitude hold are enough to keep me happy.I try and keep it as simple as possible. My Robin only has a simple wing leveller on The TC or tracking (not very well) a vor.Better than nothing though and retrofitting is horrendously expensive on Robins.vbr Stampe
Yes, but one might argue that the only time a pilot actually needs envelope protection is when he has either gone to sleep (and the copilot has also) or when he is so far behind the plane he is not even in the cockpit.
It's a bit like GPWS. It has dramatically reduced CFITs in airframes where it is mandated, but the airlines that train their pilots to some degree did not have CFITs anyway, by the time GPWS came in.
It also can be useful for low passes at airshows, but you better make sure the gear is not down because that disables some of it 
Just my opinion of course 
What I have read is that an Airbus can climb faster than a Boeing because, post takeoff, the pilot can just hold the stick all the way back as far as it will go, and the computer flies the climb right on the verge of the stall buffet, all the way up.
There was recently a case in the United States when the pilot of an SR 22 with a DFC 90 autopilot lost consciousness. He was flying over the desert at the time and, when the plane ran out of fuel, the envelope protection feature of the autopilot caused him to descend at a shallow angle such that, when the aircraft impacted terrrain, the pilot survived although he was quite badly hurt.
Jonzarno, that's very interesting. Would you have a link, by any chance?
what next, a 20 year old Citation autopilot has GPSS? Envelope protection? I had no idea!
min. clean speed is 3 knots above flap limit...work that one out ...
Stampe, out of interest - what airplane is this? Intrigued......
Jonzarno, that's very interesting. Would you have a link, by any chance?
There was a long thread on COPA but, other than that, I don't have a direct link to the story itself. Sorry!
a 20 year old Citation autopilot has GPSS?
I would say that GPSS doesn't actually do anything useful. I know many will say this is an outrageous statement but go here and search for "performance in turns". That is late 1990s technology, yet flying the LNAV profile within RNP1 (PRNAV) i.e. the max deviation is within 1nm.
It would be only during the most unusual flying that one would exceed RNP1 e.g. a descent at close to Vne and doing a 90 degree intercept onto the FAT.
And during all enroute flight the deviation is practically nil - maybe 100 yards.
The key is to have an auto-slewing course pointer i.e. an EHSI or some more modern equivalent presentation.
With a mechanical HSI the pilot has to twiddle the course pointer to the next track when the GPS tells him to, which is both good (because if you are cunning you can do it at just the right time to get a perfect intercept) and bad (if you don't do it the plane will do something daft as the deviation bar flies off to one side while it tries to fly the old track).
I think the real benefit of GPSS to many GA pilots is that they can retain their old HSI and get hands-off flight. The drawback is that you then have a dead course pointer, which is not really satisfactory for situational awareness.
I suspect the majority of big jets flying today will not do a "perfectly computed" intercept either... that needs airdata input so you start the turn at exactly the right point taking into account what the wind will be along the new track.
I know this sounds like I am minimising technology which I don't have anyway, but envelope protection in something like a Cirrus isn't going to do much at the bottom end of the speed range because the most likely reason you are about to stall is that you don't have enough power! So all it can do is point the nose downwards. There is no auto throttle.
There was a long thread on COPA
How much does it cost to join COPA, enough to read the site?
I know they have a public access section but there is little activity there. I once posted something there about that company which has the STC for the mixture lever, and got a hostile reception.
the pilot can just hold the stick all the way back as far as it will go
... only allowed in case the GPWS or any pilot calls "Terrain, terrain" - "Too low terrain" or "pull up "
