UNICOM (Universal Communications) is the VHF broadcast frequency, set to 122.800 MHz in IVAO, which is selected to send traffic information broadcast by aircraft (TIBA), named in IVAO as self announcing procedure for pilots. The aim is to report aircraft positions and pilot intentions where no active and relevant air traffic controller is available and connected.
The use of UNICOM allows all pilots to be informed of the presence of nearby aircraft movement and to know the intentions of each of them, whether on the ground or in flight, in order to prevent collision and airprox.
In the real world, Air Traffic Services are very often present. We have:
In IVAO, active control is often not present. This is one of the main differences between the real and virtual world.
Like in the real world, in the absence of air traffic control, all pilots shall ensure self-information in flight and on the ground. This is a mandatory procedure (it is not optional). This is known in real aviation as Traffic Information Broadcasts by Aircraft (TIBA) or self announcing procedure in IVAO.
In IVAO, the solution was to choose a unique self-communicating information service on a defined frequency 122.800MHz named UNICOM for all airspace and all airfields. Any message on this frequency shall be sent in text mode only on UNICOM.
What you should know about Unicom:
UNICOM is used by pilots in command of an aircraft to:
In summary, the use of UNICOM allows all pilots to be informed of the presence of nearby aircraft movement and to know the intentions of each of them, whether on the ground or in flight. This is called Situational Awareness: know where you are, who is around you and what is happening.
To do this, you must submit your intentions on UNICOM in advance so that everyone can correctly anticipate the actions of others.
All UNICOM transmission must use text mode only (via IVAO pilot software) and the transmission shall be made in aviation English. No voice can be used.
English to be used are the basic words from standard phraseology. The use of codes and text shortcuts are permitted.
There are six ICAO languages used in aviation (English, French, Spanish, Arabic, Chinese, and Russian). Sometimes the local country ICAO language is used instead of English. Please pay attention that the use of another language (other than English) does not allow self-information as effectively with foreign pilots!
Why UNICOM voice cannot be used:
- Having several hundreds of pilots voices on the same frequency would not be feasible
- The voice servers cannot filter channels according to distance
- There are not enough voice servers to accommodate everyone on UNICOM (saturation)
- Those who do not speak English would be penalized.