'Ullo, everybody...
Originally Posted by
Machinbird
Maybe they really should tell you something that you really might need to know like "Alternate Law" or as in the case of the Perpignan A320, "Direct Law."...
The Flight Control Law shouldn't really matter that much. In real terms, Alternate Law means "take extra care with your inputs, as it's now possible to stall your aircraft" and Direct Law means exactly the same with the addition of "...and you have to do the trim yourself". No matter what control law one is in, you should never deflect your stick to the stop unless you've got a damned good reason to do so.
Originally Posted by
Machinbird
All circumstantial except for one thing. Just why was AF447 oscillating in roll during those first 30 seconds?
Didn't we cover this a few months ago?
Originally Posted by
DozyWannabe
It may be possible that the roll direct aspect of Alt2B might have thrown Bonin initially, but consider these points:
- Bonin had *no* training or experience in high-altitude manual handling in Normal Law, let alone any of the Alternate configurations - how could he have known what to expect (put another way, how could he be 'thrown' or 'confused' by the control law change when he had no prior experience with which to compare it)?
- Take a close look at the "Lateral Wind" graph alongside the pink trace on the "Roll Attitude" graph. At the moment Bonin took manual control, a 25kt right crosswind with an updraft component suddenly dropped sharply. The pink trace indicates that even with no input, the simulated aircraft actually rolls about 2 or 3 degrees to the left from inertia.
- The right crosswind returns and averages around 30kts for the next 12 seconds, but at this point, Bonin's initial overcontrol to the left has him disorientated and making input reversals.
No matter what control law you are in, or even if you're in a type with traditional controls, I'd imagine that kind of initial quick reversal would be very tricky to damp out manually, and practically impossible if you've just been handed control from the AP with little warning. The return of a near-constant right crosswind for the next 12 seconds can only complicate matters further.
Originally Posted by
Goldenrivett
Better tell BAE they are wasting their time then.
...
"The biggest drawback of the “passive” sidesticks now used in civil aircraft is the lack of control feedback from the aircraft or the other pilot."
Of course, being sales literature, they don't enumerate the potential benefits (e.g. what happens when someone wires one side up backwards?)
PJ2 has the right of it here, and so (for the most part) does Clandestino.