The ups and downs of Australian air traffic control
Box 1 | The beginnings of air traffic control in Australia
In the beginning, there was no air traffic control. The aviation pioneers flew where they liked, when they liked. There were few aeroplanes about, so the chance of a mid-air collision was pretty remote.
But there were plenty of other hazards. The flying machines were less reliable than they are today and information on weather conditions was scant. In addition, navigation was hindered by poor maps, basic instruments, and no radio contact with the ground. True, help was sometimes obtained at ground level, but in a way that would be considered somewhat cavalier today. For example, the story is told of one Qantas pilot flying in the Northern Territory in the 1920s who swooped low over a bushman and switched off his engines while he yelled for directions.
Early air disasters were catalysts for air traffic control
It was only after a few major air disasters that people started to consider the need for the control and monitoring of planes in the air. One of the most significant was that of the Southern Cloud, which crashed on a flight from Sydney to Melbourne in 1931, killing the two crew and six passengers on board. Although its wreckage was not discovered for 27 years, the disappearance of the Southern Cloud prompted an investigating committee to advise that all passenger aircraft should be equipped with two-way radios. In addition, ground radio stations should be established to communicate with the planes and to monitor progress towards their destinations.
The loss of the Kyeema in 1938 was another catalyst for the introduction of air traffic control. Due to a navigation error, this airliner crashed into the side of Mt Dandenong near Melbourne, killing the four crew and fourteen passengers on board. An inquiry later suggested the need for a system 'whereby the movements of aircraft could be checked by a competent person on the ground'.
Techniques and technologies from World War II
Air traffic control really kicked off in Australia after World War II, when technologies and techniques developed during the war effort were adapted to civilian use. One of these was radar, used by air traffic controllers to pinpoint the location of aircraft. Radar assisted in aircraft separation near airports and was also useful for 'talking down' an aircraft which had suffered an instrument failure or whose pilots were unable to navigate visually due to darkness or bad weather.
Another technique was the instrument landing system (ILS), improved from the wartime 'standard beam approach' and installed at all major airports in Australia shortly after the war. The ILS operates in the following way. A transmitter located at the airport sends out two beams that can be picked up by an approaching aircraft. One beam, called the localiser, keeps the pilot from moving away from the correct approach path. This path projects as an extension of the runway centreline. An instrument in the cockpit shows divergence from the correct path with a vertical needle. The other beam, the glideslope, gives the path the plane should take downwards – a horizontal needle shows the pilot whether the plane is above or below the correct glide path. In theory, pilots don't need to look out the window (until very close to the landing strip) – all they need to do is keep the localiser needle vertical and the glideslope needle horizontal to arrive safely at their destination.
Radar, ILS and other techniques formed the basis of post-war air traffic control. They are still in use today, although they have been modified in various ways.
Related sites
Air traffic control – Part 1
(Airways Museum and Civil Aviation Historical Society, Australia)
Air traffic control – Part 2
(Airways Museum and Civil Aviation Historical Society, Australia)
Edward George Bowen (Biographical Memoirs, Australian Academy of Science)
Frederick William George White (Biographical Memoirs, Australian Academy of Science)
Page updated February 2005.