Airports (in the United States) lacking a tower are sometimes served by a UNICOM radio. The UNICOM frequency gives pilots a common channel to communicate their intentions to other pilots in the vicinity of an uncontrolled airport.
It is generally required that pilots of aircraft having radio equipment permitting two-way communications should contact the Airport UNICOM to obtain advisory information and announce their intentions when within ten (10) miles of the Airport. Pilots are also encouraged to maintain a listening watch on the frequency when operating within a ten mile radius of the Airport. All departing aircraft shall announce on the UNICOM their intention and runway to be used for departure.
On initial contact, pilots report altitude, aircraft type and identification, and location relative to the airport and state their intention, to land or overfly.
Pilots give a status report on downwind, base and final approach.
FlightGear does not fully implement UNICOM entirely. UNICOM works best in multiplayer, where you actually have listeners.
- To access UNICOM, press the dash key (-) to enter the radio chat menu. Press the number that corresponds to '[XXX TRAFFIC]'
(where 'XXX' corresponds to the airport you are closest), then choose your message.
Air Traffic Control
|Air traffic control|
Air traffic control (ATC) is a service mostly provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other support for pilots when able. In some countries, ATC may also play a security or defense role (as in the United States), or actually be run entirely by the military (as in Brazil).
FlightGear and ATC
FlightGear suppots several ATC systems.
- ATC chatter: to hear some random records of real-ATC, enable "Chatter" at the File > Sound Configuration dialog.
- ATIS: set COM1 to the ATIS frequency to hearr ATIS for the choosen airport. Unfortunately this is broken in FlightGear 1.9 and 2.0.
- Multiplayer text-chat: occasionaly someone plays the "tower" at the multiplayer server by using the ATC-aircraft. You can communicate with Multiplayer > Chat Dialog or by using predefined messages with Multiplayer > Chat Menu.
- FGCom: as an alternative to text-chat, there is the ability for voice communications over the multiplayer network. Be aware that not all controllers/pilots have FGCom.
- ATC-FS an ATC aircraft with flightstrips.
- ATC phraseology lists common phraseology and their meanings.
- ATC Tutorial to find out how ATC should be used.
- ATC best practices lists a number of best practices to be followed in controlled areas.
The Automatic Terminal Information Service is broadcast from most airports, informing about active runways, weather and conditions, exceptional airport information, etc. It is typically recorded every half-hour by controllers and looped over on a published frequency for pilots to listen before making contact.
Look up the ATIS frequency of an airport in range and set it to COM1. With the somewhat misleadingly named "ATC" sound configuration option, you will hear a faint broadcast automatically generated by FlightGear. In a controlled multiplayer session and with FGCom turned on, you may hear a proper ATIS if it was recorded by the ATC. Always tune in first! Alternatively, you can be given one though multiplayer text chat.
Most radio racks have similar controls. As an example look at the Kx165 VHF communication transceiver and VHF navigation receiver.