Originally Posted by
Gretchenfrage
Second, I consent that some pilots were involved in design. But which ones?? Most probably management pilots and technical pilots. Now most experienced line dogs will agree, that they are not bad guys, but somewhat estranged to daily operations.
As I understood it the group from which requirements were drawn involved a fairly broad cross-section of pilots.
The big issue with Airbus was and still remains the lack of feedback on controls. They let their aircraft use one single channel to communicate with the pilot, the one through the eye, meaning an intellectual, a serial input to the brain. To a small degree they use the audio channel as well, however in this particular case shows how small: The THS movement is not audio connected, you can’t hear it moving, you need to look at it again, with your single serial channel.
I'd venture to say that *your* big issue with Airbus is the lack of tactile feedback. You're not alone, Heino Caesar of Lufthansa felt the same way - however a lot of pilots have no issue whatsoever with it.
You can buy a rumble joystick and a simple thrust level duplicator for a few bucks in any game shop (not wanting to implement such a cheap solution remains therefore a matter of pride and principle).
If you really believe it's that simple, give it a try, and good luck getting that gear certified. "Pride and principle?" - rubbish. In order to pass certification the devices have to be proved to be able to resist failure to a probability ratio of 10^-9 per hour. My CH simming gear went back twice - the first time failing after 6 months, and that was kept in a dry, sealed box, not constantly exposed to the ever-changing temperature and humidity of a line aircraft - though somewhat ironically, the cheapo rumble stick that I used when flying the A320 sim (sadly, I don't have the free time anymore) never gave me a day's trouble.
We only need the tactile feedback serving the other channel input to our brain.
Who do you mean by "we"? If you mean pilots, then it's clear that a significant number consider it a "nice to have" rather than a necessity in day-to-day operations, otherwise Airbus would never have been able to challenge Boeing in the airliner stakes.
If you mean human beings in general, I'd say that it becomes a matter of training and what we become used to. I maintain that tactile feedback is useful in the initial training scenario in order to accustom the pilot with the inputs required to maneouvre the aircraft, and additionally to understand the factors of how air resistance affects the control surfaces at various attitudes and speeds - in line flying, when you're supposed to have all that stuff (as well as stall recognition and recovery) down, I (along with others) don't see it as so much of a necessity.
WHY DEPRIVE THE HUMAN OF AN INPUT CHANNEL INTO HIS CONTROLLING DEVICE? A CHANNEL THAT IS OLDER AND MORE INSTINCTIVE AND MUCH FASTER THAN THE ONE HE LATER AQUIRED, THE INTELLECTUAL ONE?
No need to shout. As I said earlier there are several things to take into account. The A320 project went onto the drawing board in 1982 and was just about ready to enter service by 1988. This meant that in those 6 years (which is by no means a short time to develop an airliner) every new system had to go through a long certification process which, coupled with the engineering complexity maxim, meant that those systems had to be kept as simple as possible.
Combine this with the fact that the hardware specified had to be proven and therefore a few years old at the time. I'd hazard a guess that the hardware was specified around 1985, which meant the venerable (in computer terms) 80186 (introduced 1982) and 68000 (introduced 1979) were pressed into service. They were quite advanced for their time, but even by the standards of the late '80s and early '90s they were fairly low down the pecking order performance-wise. When Boeing caught on to how the airlines were responding to the new FBW offerings and put the 777 on the drawing board, they had more advanced proven technology to work with, and so the complexity of a force-feedback system was less of a challenge. Added to which the FBW concept in general had been proven by Airbus, so Boeing probably had an easier job getting their basic control logic systems certified in the first place.
As a pilot being placed into the modern cockpit to supervise and program the automation and to intervene when it screws up, I need all the channels and inputs I can get, especially the parallel ones, as my brain starts working more constrainly in stress.
What this tells me is that you have an innate distrust of technology, and that colours your perception of the systems - which is quite ironic given that the modern Airbus and Boeing systems are designed to degrade quite gracefully - they've convinced the certification authorities and the regulators that they won't automatically control you into an unstable attitude and then hand you back the controls, yet you seem to be fully convinced that they will.
Now I'm not saying they won't or can't, but I believe the chances of it happening are suitably remote, and I hope that given a competent pilot, the aircraft is capable of being recovered in the highly unlikely event that they ever do.
You can point at the not using the unreliable speed checklist, badly using the stall recovery procedure, not realizing the THS position, not knowing that the stall warning goes out below 60kts, being slow in realizing that the AT was off, the lever position not where the power was, having tocheck on ECAM and click up and then down with it, etc. etc. (all single channel eye-brain operations).
That's a fair amount of conjecture in there, and a couple of outright misapprehensions. They didn't perform the stall recovery procedure *at all*, the PNF clearly called out that A/P and A/THR were off, followed by announcing Alternate Law - and none of us know whether the PNF was ever "head down" reading the ECAM messages, let alone scrolling through them - he certainly seemed to be aware enough of how the PF was controlling the aircraft to tell him several times that he was overcontrolling in pitch and roll.
But what bugs me more is the switching of stick priority back and forth, no double inputs, as this is not allowed, the swinging of the stick up-down-left-right, the moving of the thrust to TOGA-idle-TOGA and so forth, the shouting “I have no control”.
He had no control because he'd stalled the aircraft! Look, regarding the priority switch, the Airbus design (due to the factors I mentioned earlier) was designed to operate in an environment where the crew follow procedure, which is that one pilot should be PF and the other PNF at any given time in 99% of operational situations, and as such is an aid to enforcing CRM and flight deck discipline. Double inputs *are* allowed by the system, but they are summed, meaning that in an emergency situation, the pilots can theoretically command twice normal pitch-and-roll rate in an emergency situation if they co-ordinate properly, and that a pilot can counteract the inputs of an incapacitated pilot in the other seat if the situation is recognised. Compare that to the old yoke system whereby whoever was the strongest decided the direction of the aircraft, or the more modern yoke in the 767 when opposite inputs cause the elevators to move in opposite directions (as EgyptAir 990 appeared to prove).
It reveals a completely lost PF(no feedback on his tactile channel), a PNF that has no clue what the PF is swinging (again no tactile feedback).
Not that this would be the initial reason for the crash, but to me it certainly points to a huge weak spot of the Airbus design.
But that's just it - you're hammering the known aspects of this case into the frame of your particular dislike of the Airbus design. There's no evidence that the PNF was unaware of the inputs being made because he told the PF to ease off several times, and there's no evidence that tactile feedback would have told the PF that he was overcontrolling, and it looks like he simply had no appreciation of how little input is actually required to get positive response from the aircraft at altitude.
I know however that I will be cried down by the lobbyist and all others will shrug their shoulders and say “so what, there are so many ABs flying around and so much money involved, nothing is going to change”.
It's so easy to blame lobbyists and beancounters, because it's not well-known by the public that pilots were involved in the Airbus FBW design, that the march towards pilotless airliners was a fabrication of the press (as was the junk about the Habsheim A320 "thinking it was going to land") and that the politics being played by pilot's unions in the wake of the A320's introduction were largely a response to the cr*p being spouted by the press, and not because they'd flown the A320 and found it wanting.
Let us thus wait for the next pilot error
This wasn't just pilot error, this is a systemic problem affecting the airlines and the industry as a whole. PPLs start their ATPL training knowing how to recognise and recover from a stall - that this knowledge is not periodically revised and enforced is a sad indictment of the real issues that cost-cutting and poor corporate morale produce.