(a) A rough air speed, V_RA, for use as the recommended turbulence penetration airspeed, and a rough air Mach number, M_RA, for use as the recommended turbulence penetration Mach number, must be established. V_RA/M_RA must be sufficiently less than V_MO/M_MO to ensure that likely speed variation during rough air encounters will not cause the overspeed warning to operate too frequently.

(b) At altitudes where V_MO is not limited by Mach number, in the absence of a rational investigation substantiating the use of other values, V_RA must be less than V_MO - 35 KTAS.

(c) At altitudes where V_MO is limited by Mach number, M_RA may be chosen to provide an optimum margin between low and high speed buffet boundaries.