UNICOM[PDF]

Introduction

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.


Interest and explanation of Unicom

In the real world, Air Traffic Services are very often present. We have:

  • En-route air traffic controllers that control the FIR and UIR airspace 24h per day and are available every day of the year.
  • Major airports are mostly permanently staffed with at least one Air Traffic Control position. Usually available 24h per day or otherwise between 6h to 24h or when there is traffic. Traffic is not permitted outside of the operating hours. However, it is possible to specifically request a controller at an airport and to file a flight plan to that specific airport.
  • Smaller airports are open with an active air traffic control service during slots of commercial traffic (7h-12h 14h-21h) and on days when commercial traffic is present. Outside of these time slots, the service is limited to self-flight information for pilots on a published radio frequency.
  • Very small VFR airfields sometimes have only flight information services that are open only during day time or on weekends. Outside of these time periods, pilots rely on air-to-air self-information procedures.
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.


Characteristics of UNICOM

What you should know about Unicom:

  • IVAO pilot software is equipped with a filter that removes communication channels which are too far from your flying area.
  • Only aircraft located in your area will receive your text transmissions in IVAO pilot software
  • Only aircraft transmissions in your area will be displayed on your IVAO pilot software
  • the UNICOM frequency is unique, equals to 122.800MHz and is used throughout the world.
  • English language should be used for all messages

UNICOM is used by pilots in command of an aircraft to:

  • send information to other pilots to notify them of his intentions of flying or moving on the ground
  • to receive any information from other pilots and to be informed of their intentions and their movements
  • coordinate with other pilots for a landing or take-off procedure, for altitude separation, for negotiating on integration in the traffic pattern, or for a visual separation

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.


Text only and NO VOICE

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.

See also

Reference

  • none

Author

  • VID 150259 - Creation - Wiki integration
  • VID 150259 - Update October 2019

DATE OF SUBMISSION

  • 16:15, 13 December 2019

COPYRIGHT

  • This documentation is copyrighted as part of the intellectual property of the International Virtual Aviation Organisation.

DISCLAIMER

  • The content of this documentation is intended for aviation simulation only and must not be used for real aviation operations.