Originally Posted by
DJ77
The way we flew airplanes before FBW had been refined over decades and was satisfying almost everyone. Why change? Why did Airbus needed to invent a new way of flying airplanes? Until now, I fail to be convinced the reason was for the pilot’s better.
*Part* of the reason was, otherwise, why would they have bothered including pilots in the requirements capture phase? Also, what you're saying is just not accurate. The fact is that the "refinements" you're talking about were inexorably leading up to the point where FBW would be introduced in airliners, it was just a question of when and how. The aircraft on the drawing board in the mid-60s (B747, DC-10, L-1011) simply weren't capable of being controlled by the mechanical linkages that had been used in the past, and so the decision was made to go all-hydraulic. This led to it's own set of problems, but that's a subject for another time. FBW technology had been around since the '60s and there were a lot of advantages to it's use. It had also undergone many refinements since its introduction, making it a logical choice for fighter jets in the '70s and - as had always been the case before, what was good for the military found its way into civil aviation a few years later.
I still believe Airbus missed a trick by not instituting a pilot outreach programme at the same time it was courting airlines with the economy and safety aspects. All they had to do was say to pilots "Look, our aircraft fly like spacecraft - want to know how Neil Armstrong felt in the
Eagle?", and I suspect it may have been looked on a lot more favourably. Much is made by Airbus detractors of the involvement of Bernard Ziegler in the early days of the Airbus FBW programme, which is fair enough - he's a controversial individual who said some less-than-clever things. However not so much is made of the presence of Gordon Corps at the same time - I don't think he could be described as anything other than a "pilot's pilot", and he was *very* comfortable with the design. There's a thread kicking round here somewhere from someone who was suspicious of the A320's ability to get out of extreme situations and Captain Corps took him up on the challenge - in every case the A320 in Normal Law fared better than the conventional aircraft, albeit in the simulator.
When I first read HTBJ, I was struck by D.P. Davies mentioning that some in the piloting fraternity kicked up an almighty stink about the presence of the "stick pusher" in CAA-certified aircraft - the arguments used then were much the same as those made against the Airbus FBW system today - claims of "encroachment on a pilot's authority" etc. The "stick pusher", as many will know, was a simple hydraulic ram system designed to force an aircraft which did not have good stall characteristics (particularly rear-engined T-tail designs, but a "stick nudger" was fitted to all G-registered B707s as well) into a nose-down attitude, and yet pilots of the time still claimed that it was a technological step too far. In other words, the bunfight that always occurs when the subject of automation comes up is nothing new.
The truth is that while Airbus marketed their FBW designs as a quantum leap forward, in fact it was very much an evolutionary rather than revolutionary step in terms of aeronautics - the only thing radical about it was that it was the first time it had been applied to an airliner. Boeing knew this too, and that's why the B777, when it arrived, was basically a FBW airliner with a computer-controlled force-feedback system, kind of like how a nicotine inhaler is compared to a cigarette - the old feelings are all there, but it's artificial - under the hood it's a very similar computer-driven system to that of the FBW Airbii.
Is it just because it was not required by regulations that unless you trip the auto-trim it does not even provide classical low speed longitudinal stability in ALT law?
Whether it has "classical low speed longitudinal stability in ALT law" has yet to be confirmed - I'd need someone who's more familiar with the systems to answer that question.