GENERAL AVIATION
That portion of civil aviation that does not include scheduled or unscheduled air carriers or commercial space operations. (See ICAO term GENERAL AVIATION.)

GENERAL AVIATION [ICAO]
All civil aviation operations other than scheduled air services and nonscheduled air transport operations for remuneration or hire.

GEO MAP
The digitized map markings associated with the ASR-9 Radar System.

GLIDEPATH
(See GLIDESLOPE.)

GLIDEPATH [ICAO]
A descent profile determined for vertical guidance during a final approach.

GLIDEPATH INTERCEPT ALTITUDE
(See GLIDESLOPE INTERCEPT ALTITUDE.)

GLIDESLOPE
Provides vertical guidance for aircraft during approach and landing. The glideslope/ glidepath is based on the following: a. Electronic components emitting signals which provide vertical guidance by reference to airborne instruments during instrument approaches such as ILS/MLS, or b. Visual ground aids, such as VASI, which provide vertical guidance for a VFR approach or for the visual portion of an instrument approach and landing. c. PAR. Used by ATC to inform an aircraft making a PAR approach of its vertical position (elevation) relative to the descent profile. (See ICAO term GLIDEPATH.)

GLIDESLOPE INTERCEPT ALTITUDE
The published minimum altitude to intercept the glideslope in the intermediate segment of an instrument approach. Government charts use the lightning bolt symbol to identify this intercept point. This intersection is called the Precise Final Approach fix (PFAF). ATC directs a higher altitude, the resultant intercept becomes the PFAF. (See FINAL APPROACH FIX.) (See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE.) GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS)

GLOBAL NAVIGATION SATELLITE SYSTEM MINIMUM EN ROUTE IFR ALTITUDE (GNSS MEA)
The minimum en route IFR altitude on a published ATS route or route segment which assures acceptable Global Navigation Satellite System reception and meets obstacle clearance requirements. (Refer to 14 CFR Part 91.) (Refer to 14 CFR Part 95.)

GLOBAL POSITIONING SYSTEM (GPS)
GPS refers to the worldwide positioning, navigation and timing determination capability available from the U.S. satellite constellation. The service provided by GPS for civil use is defined in the GPS Standard Positioning System Performance Standard. GPS is composed of space, control, and user elements.

GNSS [ICAO]
(See GLOBAL NAVIGATION SATELLITE SYSTEM.)

GO AHEAD
Proceed with your message. Not to be used for any other purpose.

GO AROUND
Instructions for a pilot to abandon his/her approach to landing. Additional instructions may follow. Unless otherwise advised by ATC, a VFR aircraft or an aircraft conducting visual approach should overfly the runway while climbing to traffic pattern altitude and enter the traffic pattern via the crosswind leg. A pilot on an IFR flight plan making an instrument approach should execute the published missed approach procedure or proceed as instructed by ATC; e.g., “Go around” (additional instructions if required). (See LOW APPROACH.) (See MISSED APPROACH.)

GPD
(See GRAPHIC PLAN DISPLAY.)

GPS
(See GLOBAL POSITIONING SYSTEM.)

GROUND CLUTTER
A pattern produced on the radar scope by ground returns which may degrade other radar returns in the affected area. The effect of ground clutter is minimized by the use of moving target indicator (MTI) circuits in the radar equipment resulting in a radar presentation which displays only targets which are in motion. (See CLUTTER.)

GROUND COMMUNICATION OUTLET (GCO)
An unstaffed, remotely controlled, ground/ground communications facility. Pilots at uncontrolled airports may contact ATC and FSS via VHF to a telephone connection to obtain an instrument clearance or close a VFR or IFR flight plan. They may also get an updated weather briefing prior to takeoff. Pilots will use four “key clicks” on the VHF radio to contact the appropriate ATC facility or six “key clicks” to contact the FSS. The GCO system is intended to be used only on the ground.

GROUND CONTROLLED APPROACH
A radar approach system operated from the ground by air traffic control personnel transmitting instructions to the pilot by radio. The approach may be conducted with surveillance radar (ASR) only or with both surveillance and precision approach radar (PAR). Usage of the term “GCA” by pilots is discouraged except when referring to a GCA facility. Pilots should specifically request a “PAR” approach when a precision radar approach is desired or request an “ASR” or “surveillance” approach when a Nonprecision radar approach is desired. (See RADAR APPROACH.)

GROUND DELAY PROGRAM (GDP)
A traffic management process administered by the ATCSCC; when aircraft are held on the ground. The purpose of the program is to support the TM mission and limit airborne holding. It is a flexible program and may be implemented in various forms depending upon the needs of the AT system. Ground delay programs provide for equitable assignment of delays to all system users.

GROUND SPEED
The speed of an aircraft relative to the surface of the earth.

GROUND STOP (GS)
The GS is a process that requires aircraft that meet a specific criteria to remain on the ground. The criteria may be airport specific, airspace specific, or equipment specific; for example, all departures to San Francisco, or all departures entering Yorktown sector, or all Category I and II aircraft going to Charlotte. GSs normally occur with little or no warning.

GS
(See GROUND STOP.)