Class (G) Airspace is uncontrolled airspace that extends from the surface to the base of the overlying Class (E) Airspace. It is not depicted on a sectional chart. Additionally, no Air Traffic Control (ATC) services are provided to VFR or even IFR traffic while traversing this airspace.
Class (G) Airspace will normally begin at the surface and will extend upward to 1,200 feet AGL. Except where other airspace areas exist (such as Class B, C, or D), Class (G) Airspace will exist immediately below Class (E) Airspace.
There is no minimum pilot certificate requirements to enter Class (G) Airspace. There is also no specific minimum aircraft equipment required to operate within Class (G) Airspace.
BELOW 10,000′ MSL: The aircraft cannot exceed 250 KIAS.
ABOVE 10,000′ MSL: Once an aircraft climbs above 10,000′ MSL over the airspace that surrounds the 48 contiguous United States of America and Alaska. The aircraft may accelerate to a maximum speed which does not exceed Mach 1.0, or in simpler terms: the speed of sound; unless the operator possesses a written waiver, as per 14 CFR §91.117.
Ground Visibility is defined in FAR Part 1 as “the prevailing horizontal visibility near the Earth’s surface as reported by the NWS or an accredited observer.” If an airport within controlled airspace officially reports the weather, a pilot taking off, landing at, or entering the traffic pattern at that airport is bound by the officially reported Ground Visibility.
Otherwise, the Visibility Minimums refer to Flight Visibility, “defined as the average forward visibility observed by the pilot from the cockpit.” Therefore, an aircraft transitioning controlled airspace, but not operating at the airport, must maintain the proper Flight Visibility Minimums but is not bound by the officially reported ground visibility.