Plane: Do not pitch down below horizon level to gain airspeed in auto modes unless descending or airspeed < FBW_ARSPD_MIN + X%

When below the airspeed-trim and/or cruise airspeed, maintain airspeed with throttle and pitch up. Do not pitch down to speed up unless trying to prevent a stall. If you hit Throttle_max and still not reaching throttle trim and/or cruise speed then you've done the best you can and just carry on