ED Decision 2003/13/RM
It must be shown that the sailplane with the airbrakes extended, will not exceed VNE in a dive at an angle to the horizon of:
(a) 45° when the sailplane is approved for cloud flying and/or aerobatics when certificated in the Aerobatic or Utility Category;
(b) in other cases
(i) 30°
(ii) less than 30° when a rate of descent of more than 30 m/s can be achieved.