Lateral flapping itself isn't locked out (then the rotor would not be gimballed), however I believe there is no lateral cyclic actuator to actually control flapping in the lateral axis (yaw in AP mode and roll in helo mode is accomplished by DCP). Its my understanding that there are provisions for an actuator but it has never been installed. V-22, for example, has a flapping controller and cyclic actuator setup that can mitigate lateral flapping.
Notice the map photo and the red triangles marked "LH HIT" and "RH HIT", I suspect that the yaw oscillation caused by reduced yaw stability from a resized tail created enough unmitigated lateral rotor flapping for a set of wing strikes.
Last edited by SansAnhedral; 24th Jun 2016 at 15:36.