AA 587 /rudder use
Re various FAQs on 587 -
The reason the rudder was so sensitive is that unlike the current Boeings that use variable rudder ratio systems (full travel produces progressively less actual surface movement as speed increases) airbus dropped that system with the A300-600 and subsequent and use a variable stop. the gearing is constant but the load increases, and the maximum travel decreases with increasing speed. The effect of this when breakout forces are taken into account is that it would be very difficult to modulate such a control - but of course no one ever thought that pilots would use the control in that way... see various Aviation Week articles by the excellent Michael Dornheim.
Re jshg's query about why the A 300 didn't easily outclimb the 747 - it did, but then accelerated from 1000ft while the 747 didn't begin its acceleration and clean up until at least 2000ft, so the A300 was at one point below and downwind of the 747. Actually the wind necessary to bring the vortices into play has been quoted as only 28kt (from memory) but this refers to the component at right angles to the flight paths, and means that the total wind necessary might have been higher...unless these vortices were left lying around from some previous departure! The point is not that the vortex upset was particularly strong, but that it triggered this wholly inappropriate and uniquely AA response with the aggressive rudder inputs.
There has been a lot of puzzlement along the lines of 'I thought i could apply full control up to Max manoeuvre speed' Well, you can though whether you should really want to is debatable, but what happens with the reversals is that the aircraft yaws and overshoots the equilibrium position, so achieves a higher than normal sidleslip; if you then reverse the control, the fin load is now much higher than the either of the two design cases. These are: max deflection at zero sideslip (ie one bootful from straight and level) and max rudder in a sustained sideslip, and it is easy to see how the reversal loads will be higher. Should we all have been expressly warned of this? Well, my car handbook doesn't spell out for me what would happen if I decide to slam the shift into reverse at max speed, because they don't believe I would want to do that, and it has been the same for the aircraft builders. Of course in a country that tells you your coffee is hot, things may be different.