Air Traffic control - Ground Control vs Air Control

The purpose of air traffic control is quite complex. They’re the person who works from the control tower, giving clearance for aircraft to take off and land safely in the airport. The air traffic controller works within a system, coordinating patterns to ensure aircraft keep a safe distance in the air and on the ground. The main goal of an air traffic controller is to ensure the safety of aircraft, pilots, flight attendants, and of course, the airline passengers. An air traffic controller will communicate with pilots throughout their entire flight, relaying information back and forth between incoming and outgoing flights. They use a large system of computers, radars, and visual references during this communication. They must provide pilots with an in-depth explanation about the weather and should be prepared for any necessary flight path changes.

Ground control (sometimes known as ground movement control) is responsible for the airport "movement" areas, as well as areas not released to the airlines or other users. This generally includes all taxiways, inactive runways, holding areas, and some transitional aprons or intersections where aircraft arrive, having vacated the runway or departure gate. Exact areas and control responsibilities are clearly defined in local documents and agreements at each airport. Any aircraft, vehicle, or person walking or working in these areas is required to have clearance from ground control. This is normally done via VHF/UHF radio, but there may be special cases where other procedures are used. Aircraft or vehicles without radios must respond to ATC instructions via Aviation light signal or else be led by vehicles with radios. People working on the airport surface normally have a communications link through which they can communicate with ground control, commonly either by handheld radio or even cell phone. Ground control is vital to the smooth operation of the airport, because this position impacts the sequencing of departure aircraft, affecting the safety and efficiency of the airport's operation.

Air control (known to pilots as "tower" or "tower control") is responsible for the active runway surfaces. Air control clears aircraft for takeoff or landing, ensuring that prescribed runway separation will exist at all times. If the air controller detects any unsafe conditions, a landing aircraft may be instructed to " go around" and be re-sequenced into the landing pattern. This re-sequencing will depend on the type of flight and may be handled by the air controller, approach or terminal area controller. Within the tower, a highly disciplined communications process between air control and ground control is an absolute necessity. Air control must ensure that ground control is aware of any operations that will impact the taxiways, and work with the approach radar controllers to create "gaps" in the arrival traffic to allow taxiing traffic to cross runways and to allow departing aircraft to take off. Ground control need to keep the air controllers aware of the traffic flow towards their runways in order to maximise runway utilisation through effective approach spacing. Crew resources management procedures are often used to ensure this communication process is efficient and clear. Within ATC, it is usually known as TRM (Team Resource Management) and the level of focus on TRM varies within different ATC organisation.



Reference

https://www.natca.org/education/what-is-an-air-traffic-controller/

https://www.cfinotebook.net/notebook/air-traffic-control/air-traffic-control-tower