Defense of FBW
Salute!
First thing I want to make clear - if anyone here has flown a fully fly-by-wire plane with zero mechanical backup before 1979, then speak up. Even the Airbus has a mechanical linkage with the stabilizer ( slow, but still mechanical). The jet I flew, as with the Space Shuttle had ZERO mechanical connections or hydraulic connections between the pilot and the control surfaces. It was all electric, with computers in the way.
That being said, if anyone questions my trust in FBW, then look at the pic I posted of a wounded jet that I landed after a few harrowing minutes. The FBW system saved me from punching out, and I doubt any normal jet would have given me the opportunity to continue flying and then land the damned thing.
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All must realize that the FBW system I flew and the ones other vehicles have flown with since then do not simply convert pressure or control movement to direct movement of all the control surfaces. None!
Most have limits as to control surface movement rates and those rates are adjusted for dynamic pressure, mach, etc. So a ten pound pull might move the elevator a few degrees at 0.78 M, but move the same elevator 10 or 15 degrees when approaching the field with gear down.
Some systems place a premium upon AoA, and this too is varied according to the plane's configuration for landing or cruising or fighting.
The gee limits are the easiest to program and fly with.
With all of the above in mind, I have tried to show that flying about with a cosmic computer-assisted flight control system is not fool proof. With virtually no limits compared to the Airbus, we quickly found a way to beat the computers and wind up in a deep stall. It was a combo of aero and aft center of gravity. We couldn't get out unless we could turn off the computer control of our elevator. Only the elevator. This is prolly not a great idea for the Airbus, but who knows?
PLZ revisit the F-16 'Semper Viper" articles I have posted.
My problem with the Airbus fly-by-wire implementation is two-fold: 1) Too damned many reversion sequences and autopilot connections with the flight control computers with their laws and sub-laws and sub-sub-laws....., then 2) Flying with aft c.g. that most planes would not be certified for.
In the Viper we had to live with a possibility of getting into a deep stall and then using the manual pitch override to "rock" outta the thing. Heh heh, I am sure the PAX would like that ride in the 'bus. Until we got a bigger horizontal tail we balanced fuel forward until coming back home. This did not completely preclude a deep stall, but it significantly reduced the probability, as well as helping to get outta one quickly.
I do not recommend a "direct" control of the elevator in the Airbus for several reasons, so we have to live with what we can control tomorrow, and then maybe re-visit the reversion sequences and control rates, limits, etc.
No reason to fly with an extreme aft c.g. when there is the possibility of prolonged turbulence. I am talking about a CB and not clear air turbulence that exists for 20 or 30 seconds.
much more to discuss, but just back from TDY and have to think more.