This handbook departs from the conventional norm, in that  the airspace discussions are presented in reverse order, in  the belief that it is much easier to learn the airspace from  least complicated to most complicated; also, the information  presented for basic visual flight rules (VFR) weather minimums  is only that necessary for balloon operations.  [Figure 5-1] Other information, specifically for instrument flight rules (IFR)  flying or night flight, has been omitted, as it has little or no  value to the balloon pilot. For a complete discussion of these  issues, the balloon pilot should refer to the AIM, or FAA-H- 8083-25, Pilot’s Handbook of Aeronautical Knowledge. The two categories of airspace are regulatory and non- regulatory. Within these two categories, there are four types:  uncontrolled, controlled, special use, and other airspace.  Figure 5-2 presents a profile view of the dimensions of  various classes of airspace. It will be helpful to refer to this  figure as this chapter is studied, as well as remembering that  almost all sport balloon operations are conducted in Class  E or G airspace.  Class G or uncontrolled airspace is the portion of the airspace  that has not been designated as Class A, B, C, D, or E.  Class G airspace extends from the surface to the base of the  overlying Class E airspace. Although air traffic control (ATC)  has no authority or responsibility to control air traffic within  Class G airspace, pilots should remember there are VFR  minimums which apply while operating in it. Class G airspace  is essentially uncontrolled by ATC except when associated  with a temporary control tower.  [Figures 5-2  and  5-3] In the eastern half of the United States, most Class G airspace  is overlaid with Class E airspace, beginning at either 700 or  1,200 feet above ground level (AGL). In the western half of  the United States, much of the Class G airspace goes up to  14,500 feet before the Class E airspace begins. The pilot is  advised to consult the appropriate sectional chart to ensure  that he or she is aware of the airspace limits prior to flight  in an unfamiliar area. Most balloon operations are conducted in Class G airspace.  There are no communications requirements to operate in Class  G airspace. If operations are conducted at an altitude of 1,200  Uncontrolled Airspace Class G Airspace Airspace Classification Basic VFR Weather Minimums Airspace Flight visibility Distance from clouds Class G  1,200 feet or less above the surface 1 statute mile  clear of clouds (regardless of MSL altitude).  More than 1,200 feet above the 1 statute mile  1,000 feet above surface but less than 10,000 feet MSL. 500 feet below 2,000 feet horizontal  Class E  At or above 10,000 feet MSL  5 statute miles  1,000 feet above 1,000 feet below 1 statute mile horizontal Less than 10,000 feet MSL  3 statute miles  1,000 feet above 500 feet below 2,000 feet horizontal Class D  3 statute miles  1,000 feet above 500 feet below 2,000 feet horizontal Class C  3 statute miles  1,000 feet above 500 feet below 2,000 feet horizontal Class B  3 statute miles  Clear of clouds $_{Figure 5-1.}$  Basic weather minimums for balloon operations in the different classes of airspace. 5-2