14.class-g-airspace. Class G Airspace
Class G airspace (uncontrolled airspace) is the portion of the National Airspace System that has not been designated as Class A, B, C, D, or E. It is the only class of airspace in which air traffic control (ATC) has no authority or responsibility to control air traffic; however, pilots should remember there are visual flight rules (VFR) minimums that apply to Class G airspace.
Vertical Limits
Class G airspace extends from the surface up to the overlying controlled (Class E) airspace. The exact ceiling depends on the geographic area:
- In most of the conterminous United States, Class G ends at 1,200 feet AGL, where Class E begins (depicted by the fading edge of a magenta shaded band on sectional charts).
- In some mountainous and sparsely populated areas of the western U.S. and Alaska, Class G extends up to 14,500 feet MSL (but never higher, because Class E begins at 14,500 feet MSL nationwide, excluding airspace at and below 1,500 feet AGL and certain restricted areas).
- Around airports with an instrument approach but no operating control tower, Class E may begin at 700 feet AGL (depicted by a fading magenta ring), leaving Class G below.
- Near nontowered airports without instrument procedures, Class G may extend up to the base of the overlying Class E.
VFR Weather Minimums
VFR cloud clearance and visibility minimums in Class G are the least restrictive in the NAS, but they vary with altitude and time of day. Per 14 CFR 91.155:
1,200 ft AGL or less (regardless of MSL altitude):
- Day: 1 statute mile visibility, clear of clouds.
- Night: 3 statute miles visibility, 500 ft below, 1,000 ft above, 2,000 ft horizontal from clouds.
More than 1,200 ft AGL but less than 10,000 ft MSL:
- Day: 1 SM visibility; 500 below, 1,000 above, 2,000 horizontal.
- Night: 3 SM visibility; 500 below, 1,000 above, 2,000 horizontal.
More than 1,200 ft AGL and at or above 10,000 ft MSL:
- 5 SM visibility; 1,000 ft below, 1,000 ft above, 1 SM horizontal from clouds.
A limited exception exists at nontowered airports operating in Class G: an airplane may be operated clear of clouds with at least 1 SM visibility in the traffic pattern within ½ mile of the runway, provided the pilot maintains visual reference to the surface.
Operating Rules and Communications
No ATC clearance is required to operate VFR or IFR in Class G airspace. There is no requirement to establish two-way radio communication with any facility, and a transponder is not required by airspace class alone (Mode C/ADS-B Out are still required above 10,000 ft MSL except within 2,500 ft AGL, and within Mode C veils, regardless of class).
IFR operations in Class G are legal but unusual. A pilot may file and fly an IFR flight plan, but ATC does not provide separation services until the aircraft enters controlled airspace. IFR cruising altitudes in Class G follow the standard hemispheric rule above 3,000 ft AGL: odd thousands on magnetic courses 0°–179°, even thousands on 180°–359°.
Speed Limits
The general speed limit of 250 knots indicated airspeed (KIAS) below 10,000 ft MSL (14 CFR 91.117) applies in Class G as in all other airspace.
Practical Considerations
- See-and-avoid is paramount; without ATC traffic separation, midair collision avoidance is entirely the pilot's responsibility.
- Use CTAF at uncontrolled airports to self-announce position and intentions.
- Be alert that the Class G ceiling can change abruptly along your route — crossing under a magenta ring drops the ceiling from 1,200 ft AGL to 700 ft AGL, and the cloud clearance requirements remain the same below those Class E floors but become stricter once you climb into Class E.
- Many remote areas of Alaska and large parts of the mountainous West retain Class G to high altitudes, making it a common environment for backcountry and bush operations.
Example: A pilot is flying a sectional route under a 1,200 ft AGL Class E floor at 1,000 ft AGL during the day. With reported visibility of 1.5 SM and a scattered cloud layer at 1,200 ft AGL, the flight is legal — Class G day rules require only 1 SM and clear of clouds. If the same flight occurred 30 minutes after sunset, however, night Class G minimums (3 SM, 500/1,000/2,000) would make the flight illegal.