PJ2:
AA586 is not the only example of an aircraft loss after the VS was lost in flight. The B757 involved in the midair collision over Switzerland a few years ago had it's VS removed in the collision but was otherwise intact. The crew flew on for a while but ultimately lost control and crashed. In modern swept wing transport aircraft, yaw damping is provided through the rudder and directional stability by the vertical stabilizer. Loss of both would soon lead to uncontrollable roll/yaw oscillation, ie Dutch roll. The fact that the AF engines were found with the main wreckage would seem to indicate that they were with the aircraft at impact. If the VS and rudder had come off in flight, it might be expected that they would been found some distance away, as the kind of lateral forces which detached the AA586 engines would have occured in this case also.