How do pilots learn where the protection limits are?
They read and understand their manuals.
Stop your disinformation please.
Good advice, wrong address.
MacMillan committed suicide and lived to tell about it.
Not this MacMillan. Do you perchance live in a country where googlesearch of "Who killed MacMillan?" is blocked? Try with: FlightSafety Foundation, Accident prevention, November 1989.
Airbus pushed hard for more automation, and their airliners are more automated than any other types of the same vintage.
Simples. It was cutting edge at the time. Not any more. Nowadays it is proven, reliable and well known system - except for those who don't want to know.
As an engineer speaking, there is no man-made aircraft, engine, control system, software or whatever, however you want to cut it, that can't be improved upon, period!
Real world engineers know that no improvement comes without costs, either strictly financial or improvement in one area is inseparable from degradation in other. It's a tough world outside.
The plane did exactly what it was suppose to do according to the computers and landed in the treetops.
Real world physics demands that aeroplane has enough energy for sustained flight, no appeal against that allowed or useful. Lack of energy results in either decay of airspeed and increase of AoA untill aerodynamic stall or depletion of potential gravitational energy and collision with ground or objects attached to it, such as trees. Alpha protection at Habsheim prevented first scenario from occurring but lack of energy made the second one inevitable. Such a situation is colloquially known as low & slow. Contrary to some uninformed beliefs, FBW does not include distortion-of-Newtonian-physics protection.
There is no AoA gage to consult as a cross check.
So? Procedures based on attitude gauges (two big, one small) were not followed despite competent authorities' belief that following them is way to dig out oneself out of UAS was many times validated in real world.
Yes, it is remarkable how, just before the FD reappear, the situation was improving
Another remarkable thing is how the CM2's reaction to stall warning is to keep quiet yet always to pull, eventually pulling to back stop. One never pulls to backstop on airborne Airbus unless performing GPWS or low level windshear escape, none of which are applicable at FL350.
Does he instead mean: "I've lost command of the aircraft"
Legally, he never had command of the aircraft and would have never had it unless both capt and SFO were incapacitated. If under "command" is meant knowledge and skills needed to successfully fly the aeroplane, he lacked that at the time of the accident.
We know with a large probability/certainty that the jet was flown at a high attitude as the airspeed slowed and that all the "protections" did not keep the jet from exceeding the stall AoA or even the basic limits we see in the manuals.
Simples. Air data based protections ned reliable air data to work reliably. They were not available. That's what is meant by very technical term "Alternate law".
There is an simple and effective autotrim cancel 'feature'.... just hold the manual wheel.
Correct, but there is even simpler way to make autotrim work in the opposite direction: push the stick.
Why are the jets flying so close to a mach limit?
It's cheaper that way, when the fuel is cheap and aircraft/crew time expensive. Anyway, it's not that critical as maximum operating mach has inbuilt margin, which must not be used up deliberately.
Also, in the AF447 case, a level bust could be understandable and considered as normal as the memory item for UAS states to initially adopt 5 degrees of positive attitude.
In the real world, achieving 17.9°pitch at cruise altitude when the target is 5° is not normal or tolerable. That it can turn out to be fatal is not news to some of us. Hopefully, most.
Back to the different laws, if those are not displayed in detail by the system, the degradation of subsystems is not clearly recognizable in such a human thinking process.
Protection limits are displayed all the time on PFD when protections are available. Attitude protections marks are replaced with yellow X signs when lost, alpha prot and alpha max speeds disappear from the speed tape. IMHO, clear enough for anyone who knows his aeroplane sufficiently and pays attention to speed and attitude.
Then you throw CRM into the mix and you have an solution
If the crew (C) has no knowledge (R) to draw upon, all the management (M) is useless.
Unfortunately I think some pilots may rely on the Normal flight law protection too much.
You shouldn't be thinking that. Protection activation is very serious safety occurrence and more often than not is bound to be investigated by the independent air safety investigative body, not just airline safety dept. In the first world, at least.
Folks can point out that my ancient jet was not designed for the same operational needs and requirements as a commercial airliner. Nevertheless, just divide our "limits" by certain values and you get the 'bus "limits".
Errr... similar but not quite the same. There are radical differences in protections use between Viper and 'Bus. On Viper one would go regularly to full back stick in ACT (or real stuff) to get maximum rate turn, either G or lift limited. On Airbus, intentional activation of alpha prot by pulling full back stick is reserved only for GPWS or low level windshear escape and you have to do some pretty bad planing or be once in a 10E4 lifetimes unlucky to get there. DozyWannabe seemingly cannot get the message through, the one that all Airbus pilots must be familiar with: protections absolutely do not interfere with normal flying, they stop the pilot from doing something that he shouldn't be doing.
I'd be inclined to think that using full back stick in windshear escape is using the tools provided well, but he's right that the trainng should include the caveat that full deflection should be used as an emergency measure only, and only when the control law has not degraded.
I think you are now talking about dumbing down the pilot training down to level of system operators, which is impossible. Pilots have it covered on the very first page of any Airbus manual, the one stating this manual does not cover what the basic airmanship should. Airbus manual is not meant to teach people how to fly, but to acquaint the proficient pilot with the peculiarities of the aeroplane. If your protection is dependent on the correct functioning of a system and system goes AWOL, knowing you will lose the protection is not just basic airmanship. It is basic intelligence.
That is why I lean toward an internal dialogue inside each head "with airspeed unreliable, stall warning must be spurious."
Could be, but chances are very low. It is not unreliable airspeed but rather ADC DISAGREE that is either result of pitot, static or AoA disagreement, with spurious stall warning effected only in the last case. It would be possible to think that "unreliable airspeed" implies "unreliable stall warning" but it would take quite a lot of creative misunderstanding and magical thinking to get there.
While the internal dialog of the doomed crew is matter of considerable conjecture even for experts, CVR and FDR readouts show utter confusion and tragically maladjusted reactions. Stall warning goes uncommented, except for CM1 comment "Qu’est-ce que c’est que ça ?" It did go off a few times while commander was back in cockpit, yet even he did not consider worthy of commenting on it. CM1 recognizes and verbalizes that speed indications are lost, only to exclaim "Fais attention à ta vitesse!" (watch your speed!) ten seconds later. We are looking at the three pilots who went into territories totally unknown to them, got thoroughly scared and managed to kill themselves and all on board through panicky reaction. How and how much did the aeroplane, regulators, airline and pilots themselves contributed to tragic inability to cope with minor malfunction is something that has to be resolved. Last thing I want to see in the final report is that BEA was unable to determine what made the crew's situational awareness fall to pieces and confession "I killed Bonin" twentysomething years later.
EDIT:
It´s not a question to stay inside the envelope, it´s a question how to do that
Tens of thousands pilots do it every day. Staying inside envelope we call "flying", excursions are called "falling".