Types of Service

Radar Control Service

When aircraft are flying within controlled airspace such as airways, they are usually under the positive control of ATC.  This means the controller will issue positive intsructions to the aircraft such as speed, level and heading control.  Airacraft being transferred from one unit to the next remain under positive control and details of the flight are co-ordinated prior to handover by the controller.

Radar Advisory Service

Outside controlled airspace, when under this service, the controller will give advice on all actions necessary to maintain seperation from other aircraft.  Pilots can choose not to take the advice, but are assumed to be doing so, unless they inform ATC otherwise.  If the pilot does not follow the advice from the controller, then the pilot assumes responsibility for any further avoiding action.  Under RAS, the pilot must inform the controller of all changes to level and heading.

Radar Information Service

Under this service, a controller will issue information on other known aircraft, but it is up to the pilot to choose what action to take if necessary.

Flight Information Service

All aircraft talking to an Air Traffic Unit automatically receive a minimum of a Flight Information Service.  This is generally a service from which the pilot can obtain information such as aerodrome and navigational aids serviceablility, weather, airways crossing clearances and known conflicting traffic information.

Distress

Based at LATCC and SATCC is service provided on dedicated frequencies, frm which a pilot can obtain assistance in the event of an emergency.  There are two frequencies used which are 121.5mHz and 243.0 mHz which are the International Aeronautical Emergency Frequencies.  When an aircraft contacts the station, automatic direction finding equipment can imediately pinpoint the aircraft position accurately and this information can also be displayed on a computer, overlaid onto an ordance survey map of the UK.  This system is known as auto-triangulation.   Pilots are also encouraged to make use of the service also for training purposes providing no real emergency is in progress.

Military - London Joint Area Services (LJAO)

To enable military requirements to be co-ordinated effectively with civil aircraft, an LJAO controller can operate at various sectors covering the UK.  Often, military aircraft need to cross airways and the LJAO military controller will 'work' the aircraft, whilst sat alongside the civil controller for that section of airspace, which eases co-ordination.  In addition to this, there are dedicated frequencies and sectors for the control of military aircraft outside controlled airspace.

ATIS/VOLMET Weather Information

Broadcast on particalar frequencies continuously, are stations which contain regular updated weather information.  Major airfields often have an ATIS, or Aerodrome Terminal Information Service.  This gives information on current weather conditions at the airport concerned as well as any esssential aerodrome information.

The Volmets are a set of pre-recorded phrases which are assembled from actual and forcast weather reports, and gives these reports for a selection of various major airports, so that pilots can check and update their information on conditions further on which they may be likely to encounter.