<P> Class G airspace includes all airspace below 14,500 feet (4,400 m) MSL not otherwise classified as controlled . There are no entry or clearance requirements for class G airspace, even for IFR operations . Class G airspace is typically the airspace very near the ground (1,200 feet or less), beneath class E airspace and between class B-D cylinders around towered airstrips . </P> <P> Radio communication is not required in class G airspace, even for IFR operations . Class G is completely uncontrolled . </P> <P> VFR visibility requirements in class G airspace are 1 mile (1.6 km) by day, and 3 miles (5 km) by night, for altitudes below 10,000 feet (3,050 m) MSL but above 1,200 ft AGL . Beginning at 10,000 feet MSL, 5 miles (8 km) of visibility are required, day and night . Cloud clearance requirements are to maintain an altitude that is 500 ft below, 1,000 ft above, 2,000 ft horizontal; at or above 10,000 ft MSL, they are 1,000 ft below, 1,000 ft above, and 1 mile laterally . By day at 1,200 feet (370 m) AGL and below, aircraft must remain clear of clouds, and there is no minimum lateral distance . </P> <P> It should be noted that there are certain exceptions where class G extends above 1,200 feet AGL . This is usually either over mountainous terrain (e.g., some areas in the Rocky Mountains), or over very sparsely populated areas (e.g., some parts of Montana and Alaska). </P>

The airspace system designations used throughout the united states