Phoenix
Are we looking to a Dutch roll mode or to an adverse yaw damping?
Good question! but impossible to answer definitively from the published DFDR traces.
OTOH:
One cannot roll the aircraft without exciting all three lateral modes, so dutch roll behaviour must be in there somewhere!
IIRC the outer ailerons are locked out at high speeds and with much of the rolling moment coming from spoiler deflection on the downgoing wing I would think it quite difficult to generate any significant adverse yaw.
PS: Looking at the traces again with a critical eye I see there was a permanent small rudder trim offset ( 0.5 deg right rudder) which could have generated a slow spiral divergence to the right.
PPS: I am now reliably informed that this apparent indication of a standing trim offset is a quirk of the A330 design - something to do with dis-similar metals in the linkage and changes of temperature apparently. This would make my speculation a nonstarter, but to maintain thread continuity I'll leave it here.
Last edited by Owain Glyndwr; 20th Sep 2014 at 07:58.
Reason: adding PPS