Quote from
TyroPicard:
"Out of interest are you anti side-stick or just anti-the lack of interconnection? I have been thinking about the difficulties and implications of connecting them and have concluded that if you choose side-sticks for their amazing precision you can't connect them."
Very tricky question, and perceptive follow-up. You may remember I've stuck my neck out on PPRuNe before on the characteristics of sidesticks, and how some pilots abuse them (physically, not verbally).
Re the first part, I liked the sidestick from the first simulator session at Blagnac. However, certain combinations of roll and pitch commands can become less coordinated than one would like, even in Normal Law. The interface between sidestick and FBW in Roll Normal complicates the handling of the wing-down technique (after de-crab) in crosswind landings, but "bumping" the stick seems to work well. The (AF447) combination of Pitch Alternate with Roll Direct, however, would not be a comfortable one.
Re the second, the lack of interconnection makes it impossible for the PNF to monitor the stick handling of the PF in flight, doesn't it? Can be a real problem, particularly when you are "giving away" a landing in a gusty crosswind. But even in smooth weather I've watched guys from my frequent perch on the P3 seat (line checking), and over-use of the sidestick is all too common. It seems to be a form of occupational therapy for some when the adrenalin is going. Sometimes this leads to PIO, sometimes not. We know that Bernard Ziegler ruled out interconnection at a very early stage in the design process, presumably for weight and reliability, although the latter has been perfected in all other dual-control aircraft.
But now you raise the other problem with interconnection. Due to its size, relatively-small, quick, brief movements are the norm (two exceptions being rotation on take-off, and a roll from full bank one way to full bank the other). I'm no engineer, but if these movements had also to power the complimentary movement of a system of cable and pulleys (or anything else mechanical), the hand force required would be great (and the best way to use the sidestick is with finger-tips and thumb). Is that your point?
Any interconnection, therefore, might have to be via electronics: presumably using servos. The throttle levers work brilliantly in manual thrust, but the command from the transducer is one-dimensional and the signal time to the FADEC may be less critical. Could a sidestick system work in both directions, and would it be accurate enough and quick enough? Could the sticks be allowed to be in different positions, as at present, and would the algebraic sum still apply? How would the PNF assert control as PF?
That brings us to your final point:
"I never found non-moving [non-driven] T/L a problem - did wonders for my N1 scan!"
We know the throttle levers have transducers, but no servos, so could they have both? The reluctance of some fleets and individual pilots to using manual thrust is partly because of the awkwardness of the transition from auto to manual (not to be done at 100ft on the approach, as I’ve seen so often). Also, in my opinion, the pilot desire for extra thrust on the (rare) occasion that the A/THR is too slow to react to a tailwind shear is not adequately catered for by the (retrofitted) feature whereby the pilot briefly advances the levers from the CLB detent. This crude expedient could get you into a lot of trouble on the approach to a short runway like Jersey. That’s why nearly all my “manual” approaches were in manual thrust.