These are the aerial experts controlling our flights
Correspondent BOB HOPKIN takes a look behind the scenes at a vital component of our travelling safety – Air Traffic Control.
THE visible face of airline safety – the captain with his four gold-striped epaulettes, the first officer and the professional cabin crew – is a familiar and a respected necessity of every commercial flight.
What they do to ensure a safe and comfortable flight is accepted by all regular fliers: timely departure, bump-free climb to cruising altitude, avoiding bad weather turbulence, on time or early arrival and smooth landing are the marks of an enjoyable and safe flight.
A sobering thought, however, according to popular app and website Flightra-dar24.com, is that some 3,300 aircraft are in flight worldwide at any one time,
carrying about 660,000 passengers high above Earth.
The task of keeping all these aircraft en route but separated from each other is the domain of air traffic control (ATC).
In a local context, a recent visit to the ATC tower at George airport (CGRT in aviation parlance) revealed several interesting details of how the system works in SA.
Although Airports Company SA (ACSA) manages most of our major commercial airports, the air traffic control function is sub contracted to Air Traffic and Navigational Services SOC Ltd (ATNS) who train, equip, and staff all the control towers at each of ACSAs airports.
In a smaller airport like George, there are usually just two AT controllers on duty and in touch with incoming. overflying, and departing aircraft.
According to ATNS Officer in Charge of Air Traffic Services at George Airport Lucinda Slander, the best way to understand the complexities of ATC is to imagine the scenario of an upside-down layer cake, where the greatest breadth of control would be the international air lanes.
Then, at the national level, the country is divided into regions controlled by either Johannesburg or Cape Town airports. The final local level layer is where an individual airport’s ATC function controls its immediate area.
In the case of George, Lucinda has at least two. and sometimes three, staff monitoring and communicating with aircraft – firstly at the Approach’ level, when aircraft are still some hundreds of kilometres distant but coming into George airspace, and then at ‘Tower* level, when another controller takes over just prior to landing and until just after take-off.
The latter also controls the aircraft’s movements on the ground to avoid collisions.
The now familiar ‘white mushroom’ George Radar dome and tower adjacent to the N2 near the airport is the primary source of location information for the Approach controller, as it gives the precise locality of every aircraft within several hundred kilometres.
The hard and fast rule is that aircraft must be separated by a minimum of 5 miles (8.1km) in distance and 1,000 feet (305m) in altitude.
The output of this and every other radar dome is integrated nationwide in the Multi Radar Tracking system and this, combined with the onboard aircraft TCAS (Traffic Collision Avoidance System), makes an airborne collision practically impossible.
These fact, and the obvious competence and training of staff at George ATC, gave this reluctant flier the reassurance that flying really is the safest way to travel.
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