Private Pilot Flight Training and Instruction Flight Training Article Library | Back To 4VFR.COM Special Use Airspace (SUA) Not on charts but often mentioned by VOR/Tower broadcasts. Locally by Livermore ATIS to warn of National Guard firing range near Danville/San Ramon border as being "hot". Best way to avoid incursion problem is to file IFR. An IFR clearance that transits a SUA does not allow flight through that airspace unless ‘cleared as filed’ is a part of the clearance. If the airspace should become ‘hot’ while enroute you will be issued an amended clearance. Written by Gene Whitt Flight Training Article Library | Back To 4VFR.COM