Wednesday, October 31, 2007 Duo Discus XL becomes certified for simple aerobatics! By FlyingNews @ 12:53 PM :: 576 Views :: 0 Comments :: Gliders The improved effectiveness of the airbrake system makes it now possible for us to apply the approval for simple aerobatics including spinning. It's now possible to fly from the back seat without any operating handicaps. These features extend significantly the spectrum of use. Further there are many surprising solutions, like the changed water valve lever.