Air Traffic Services Outside Controlled Airspace (ATSOCAS)
(Note: this acronym has no meaning outside of UK)
In the UK Air Traffic Services Outside Controlled Airspace (ATSOCAS) are provided by both civil and military air traffic control units to a variety of airspace users ranging from commercial airliners to military fast jets and general aviation aircraft.
The UK’s Air Traffic Services Outside Controlled Airspace offer four levels of service:
A Basic Service is intended to offer the pilot maximum autonomy and the avoidance of other traffic is solely the pilot’s responsibility. The controller/FISO will pass information pertinent to the safe and efficient conduct of flight. This can include weather, changes of serviceability of facilities, conditions at aerodromes and general activity information within a unit's area of responsibility.
A Traffic Service provides the pilot with surveillance derived traffic information on conflicting aircraft. No deconfliction advice is passed and the pilot is responsible for collision avoidance. A Traffic Service contains the information available in a Basic Service. In addition, controllers provide surveillance derived traffic information on relevant conflicting traffic. Headings and/or levels may also be issued for positioning and/or sequencing.
A Deconfliction Service provides the pilot with traffic information and deconfliction advice on conflicting aircraft. However, the avoidance of other aircraft is ultimately the pilot’s responsibility. A Deconfliction Service contains the information available in a Basic Service. In addition, controllers shall aim to assist the pilot with his responsibility for the safety of the aircraft by passing traffic information and deconfliction advice. Headings and/or levels will also be issued for positioning, sequencing and/or deconfliction advice.
A Procedural Service is a non surveillance service in which deconfliction advice is provided against other aircraft in receipt of a Procedural Service from the same controller. The avoidance of other aircraft is the pilot’s responsibility.
ATC Service similar to ATSOCAS may be available in other territories and if it is, details may be found in the ENR section of the State AIPs.