The control frequencies (also referred to as control channels) are the channels that planes are controlled on in the AH series
Description
The approach channel handles incoming flights
Tower Control handles planes in the vicinity of the airport and it's runways.
Ground Control handles planes on the taxiways
Delivery Control handles planes leaving the gate
Ramp control (Only in AH Narita) handles planes on the apron
Departure Control handles planes leaving the airport
The control frequencies are a crucial part of the game. They allow the tower to communicate and give orders to aircraft. The channels are color-coded. There are 5 control channels in AH Honolulu and AH Kansai:
Each channel controls a specific part of the airport or a specific flight. In AH Narita, there was a sixth channel called Ramp Control that separated the taxiways from the apron of the airport. Since this channel mostly added confusion and made other channels busier, it was removed for Osaka-KIX and likely will not appear in future games.
These are short descriptions for each channel's purpose. For more information, visit the channel's full page.
Approach Control
Approach Control is coded blue on the panel and controls all planes that are preparing to land at the airport. Their main job is to guide the plane to a runway.
Tower Control
Tower Control is coded red and manages planes near the airport and the runways. It is Tower Control that gives landing and takeoff clearance, for example
Ground Control
Ground Control is labeled yellow on the panel and handles all planes on the ground. In AH Narita, they only control the planes on the taxiways.
Delivery Control
Delivery Control appears pink on the panel. They check every airplane's flight plan and clear it to depart before handing it over the ground control for pushback
Departure Control
After a plane takes off, they are handed over from tower control to departure control. It is coded green. They watch over every plane leaving the airport until they leave the airspace
Ramp Control
Only in AH Narita, Ramp Control manages the apron of the airport (the light gray sections near the gates). In this game, they handle pushback instead of ground control. A plane will not enter or leave the apron until they receive clearance from ramp control