Final Director

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A final director, is an air traffic controller, working at larger approach units. The final director's job is to sequence aircraft onto the final of each respective runway.

There are 3 phases to aircraft approaching to land on a runway:

The initial brings aircraft over a fixed point which is the last point of an en-route trajectory or routing. From there aircraft may start their manoeuvre to the runway or, if necessary, hold to delay on a predetermined race-track (holding) over this fixed point

During the intermediate phase aircraft leave this fixed point taking a course towards a line that coincides with the extension of the runway, some 10 to 15 nautical miles (28 km) from the runway threshold. The end of this phase is usually a track to intercept this line at an angle close to about 30-50 degrees. At this point the pilot, or autopilot, turns the plane to achieve alignment to this line. When this is achieved the aircraft is said to fly on its final track. During this phase a constant rate of descend ensures that the aircraft will touch the runway within its first 300-400 meters, said to be the runway Touch Down Zone and will use the rest of its length to decelerate and stop.

While aircraft fly this final phase in case of separation with others executing the same procedure there can be a controller charged with the task of taking care of speed and, if necessary, small track adjustments. This controller is called the Final (Approach) Controller. The application of even minor adjustments becomes critical especially in co-ordination with the Tower Control that monitors the availability of the runway for each incoming flight while another one on the runway is about to slow down and evacuate it

This is, however, a phase that does not last for a long time, something like between 3 to 4 minutes. If, therefore, a Final Controller position is necessary, this will have to be the case with airports with a large number of closely spaced arrivals where special attention is necessary to ensure they all land successfully. The case of a missed approach is never excluded of course, where a pilot may climb again to retry a new landing, but this is very costly in delay and fuel when many others follow behind.

In low traffic aerodromes, all the above phases can be executed by the same controller, called simply an Approach Controller

In some aerodromes the intermediate and final phases are allocated to one controlling position while the Initial phase is allocated to another, known as well as the 'stacker'. He mainly stacks the holding traffic over the Initial Approach Fix point as they arrive from the En Route Control and releases them to the next phase controller when he will have space to take more aircraft for the runway. This is a configuration usually encountered when there are many different entry points from various directions to an aerodrome or even more aerodromes that are very closely spaced