Based on Lyapunov exponent criterion. the aircraft lateral-directional stability during critical flight cases is presented. A periodic motion or limit cycle oscillation isdisplayed. A candidate mechanism for the wing rock limit cycle is the inertia coupling between an unstable lateral-directional (Dutch roll) mode with stable longitudinal (short period) mode. https://smokeysmountainfurnitureoutlets.shop/product-category/casual-seating-set/