In the very early days, of aviation the need for any form of control of aircraft in flight was negligible and pilots were able to use the airspace with virtually no risk of meeting another flying machine coming the other way. Flying generally was thought to be an adventurous but light-hearted sport, and it was never really considered to be a serious challenge to the more orthodox forms of transport.
The- earliest commercial flights were, restricted to daytime operation in good visibility. Provided the pilot knew the landmarks around the airfield and along the route, it was a relatively straightforward matter to follow prominent landmarks such as railway lines, roads and rivers in order to reach the destination in one piece. The only limitations on safe flight - apart from the fact that the infernal machine might fall out of the sky - were bad weather or darkness. Landings at airfields were assisted by the use of simple visual signals set out on the ground, or by signaling lamps which indicated to the pilot the direction for landing, permission to take off, and so on.
From a commercial point of view, the main obstacle to be overcome was the inability to operate at night. In the early 1920s, commercial night flights in the UK and in America were starting to follow lighted 'airways', marked out on the ground by relays of gas-fuelled beacons or, in many parts of America, by bonfires kept alight by local farmers who were paid a retainer to keep them going.
Radio aids to navigation were in their infancy at this time; where airways were eventually marked by radio beacons, they were often used in conjunction with lights, set on top of lightweight towers. In front of the tower, a large concrete slab in the shape of an arrow pointed the way along the route. The wooden generator shed nearby had large painted letters on the roof indicating to pilots the name of the beacon and. its number.
Visible lights were still the order of the day and the aircrew saw radio simply as an aid to navigation. In America, for example, bad weather ahead was signaled to pilots along the airway by a system of various lights, warning of the need to turn back or land. The need to actually regulate aircraft in the sky was still considered to be unnecessary.
However, in 1922 the first civil mid-air collision occurred over France when two aircraft met head-on whilst following one of the airways. Following this incident, urgent talks were arranged to discuss the issue of safety in general. Even so, in 1923 air travel was still in its infancy.
In 1927 the Marconi Company installed a single-channel radio at Croydon, although 'control' of aircraft was not part of the system. Position reports, estimated times of arrival and weather information were the principal issues of this new facility. Pilots continued to operate by flying visually, following landmarks along the route. To this end, the Department of Civil Aviation issued highly detailed maps and descriptive information of routes to assist the aircrew. A telephone call before departure to a distant point along the route enabled the pilot to obtain first-hand information on the weather.
Radio aids were, of course, improving steadily. Position fixing could be obtained by the pilot speaking on the radio telephone (R/T) for a few moments, while three separate receiving stations established an accurate fix; airfield landing aids on VHF were also available.
The first attempt at effective control occurred in New Jersey, USA, when a number of the major airlines grouped together to co-ordinate their flights across the country, meeting beforehand to agree on reporting points and altitudes. Radio position reports were recorded on a large chart spread across a table, and flight details were entered on a large blackboard. Incidentally, the first person to take charge of this control' situation was a woman.
World War 2, as might be expected, spurred the aviation world into greater advances and resulted in national action towards increased safety. In 1942 the Royal Air Force School of Flying Control was set up in the UK and the position of Airfield Controller was established. Before this, spare air force pilots had undertaken any involvement with aircraft control. .
A major advance towards the control of aircraft in flight came with the development of radar during the war years. Instead of relying on reports from the pilot concerning positions, headings and speeds, ground personnel were now able to identify aircraft quite independently. In fact, they knew as much as the pilots themselves.
At the end of the war, as civil aviation began to expand, the basis of air traffic control, as we know it today was taking shape. In 1950/51 the airways systems, which are in use to this day, came into effect: Airway Green One was the first, and five more airways followed soon after. ,
Today we have an elaborate and complex organized structure dealing with all forms of aviation to ensure safe and economic movements. It is difficult to imagine that the next 70 years will see changes as dramatic as those, which have taken place since World War 1. Future development will most probably be through evolution of the present system, which is working well and is trusted by those who use it. More sophisticated methods of processing traffic information to produce greater efficiency will be achieved by better. Flight management systems and improved data transfer techniques between the ground and the flight deck. Certainly, aviation and air traffic control will continue to be a subject of fascination for many years to come.