HOW AIR

TRAFFIC CONTROLLERS

KEEP AIRPLANES

APART

USING RADAR

 

Separation of aircraft as expressed in the previous page is known as Procedural Separation. However a more efficient and expeditious method of separating aircraft is by means of Radar. Many countries, in modernizing their air traffic control systems have moved to separation of aircraft by use of radar.

Radar is short for Radio Detection and Ranging and as used in air traffic services, is an electronic method of determining the location and direction of aircraft from the airport or radar station, once those aircraft are within the serviceable range of the equipment.

If you remember, longitudinal separation is the method applied to provide a required spacing between airplanes flying at the same level or altitude and along the same route. Radar separation is the most expeditious method of separation in any of two dimensions, laterally and longitudinally. Using radar, the controller can now literally "see" the location and determine the actual distance of aircraft from the airport. He can also determine the distance between the airplanes for himself, and can make use of the information to separate airplanes longitudinally or laterally (side by side). The separation applied is usually a minimum of 3 or 5 nautical miles between airplanes depending upon circumstances.

As aircraft approach to land in an active radar environment, the radar controller will instruct aircraft to adjust their airspeed and their direction of flight in a manner which will safely position aircraft 3 to 5 miles apart longitudinally, and place them on an imaginary extended straight line about 8 to 10 miles from the runway. From this position there will then be continuous movement of airplanes towards the runway, with each aircraft separated from the one in front by the required 3 or 5NMs. Departing aircraft must also be separated laterally from arriving aircraft by the required 5 NM, if not possible at the time, then must be separated vertically by 1000 feet until they cross each other and are at least 5 NM apart.

Trinidad and Tobago has recently installed a new MSSR and PSR radar to replace its old radar that was removed from service. Flight check inspection of the new radar installation is scheduled within the fourth quarter of 2009. With the cooperation of many of the Eastern Caribbean (ECAR) States, controllers in Piarco will soon be able to provide  a wider radar service to aircraft flying above 24,500 feet throughout the island chain. This is due to  the recent capabilities to link all the ECAR radars with the final display being available to the Piarco controllers. Read More

Using only Piarco's radar system, approximately 10 % of the airspace under its control can be covered.  This percentage will increase dramatically when the new radar-linking equipment is installed and new radar displays resulting from this radar linking become fully operational. ..  Read More

In the light of modern electronic radar and radar linking equipment, you may wonder then if procedural control is not an obsolete system. The problem is that there are still many areas of the world where it would be impossible, or not practicable to install radar equipment - like over the high seas. In some cases, where it may be practicable, it is not cost-beneficial.
 

Procedural Separation

END

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