For WSC aircraft flying above 10,000 feet MSL, the visibility  must be greater than 5 SM and cloud clearances increase to  1,000 feet below, 1,000 feet above, and 1 SM horizontal.  If the WSC aircraft was not certificated with an electrical  system, an altitude encoding transponder is required per 14  CFR section 91.215. Oxygen is required for the pilot above 12,500 MSL up to  and including 14,000 feet MSL if the flight at those levels  is more than 30 minutes duration. At altitudes above 14,000  feet MSL, oxygen is required for the pilot during the entire  flight time at those altitudes. At altitudes above 15,000 feet  MSL, each occupant of the aircraft must be provided with  supplemental oxygen. Class A airspace is generally the airspace from 18,000 feet  MSL up to and including FL 600, including the airspace  overlying the waters within 12 NM of the coast of the 48  contiguous states and Alaska. Unless otherwise authorized,  all operations in Class A airspace are conducted under IFR.  Class A airspace is not applicable to WSC pilots. Special use airspace is the designation for airspace in which  certain activities must be confined, or where limitations may  be imposed on aircraft operations that are not part of those  activities. Special use airspace usually consists of: Except for controlled firing areas, special use airspace  areas are depicted on visual sectional charts.  [Figure 8-11] Controlled firing areas are not charted because their activities  are suspended immediately when spotter aircraft, radar,  or ground lookout positions indicate an aircraft might be  approaching the area. Nonparticipating aircraft are not  required to change their flightpaths. Special use airspace  areas are shown in their entirety (within the limits of the  chart), even when they overlap, adjoin, or when an area is  designated within another area. The areas are identifi ed by  type and identifying name or number, positioned either within  or immediately adjacent to the area.  [Figure 8-11] Prohibited, restricted or warning areas; alert areas; and MOAs  are further defined with tables on sectional charts for their  altitudes, time of use, controlling agency/contact facility and  controlling agency contact frequency.  [Figure 8-12] Prohibited areas contain airspace of defi ned dimensions  within which the flight of aircraft is prohibited. Such areas  Figure 8-11. Special use airspace designations as appear on  sectional charts. • Prohibited areas • Restricted areas • Warning areas •  Military operation areas (MOAs) • Alert areas • Controlled fi ring areas • Parachute jump areas  Airspace Above 10,000' MSL and Below 18,000'  Class A Airspace  Special Use Airspace  Prohibited Areas 8-8