BIK_116.80
All B707's had yaw dampers and especially the early models were quite unstable in the yaw axis. Earlier models had parallel units, later had series.
Had not heard about the RAAF accident. Nasty business, it has always ammazed me why someone would purposely switch OFF an esential system, especially rudder boost on the 707.
With two engines out on one side, the B707
Vmca (boost ON) 170 knots, (boost OFF) 235 knots. This is for the -320B advanced series.