The Birth of Air Traffic Control Celebrating 100 years of keeping the skies safe

Blurred beginnings

There have been plenty of major aviation anniversaries in recent years with many airlines celebrating their origins, but what about the birth of Air Traffic Control?

In truth, it’s not entirely clear. Unlike the first powered flight, or landing on the Moon, there is no single definitive moment to point to. But as civil aviation emerged after the First World War, a need to safely support growing levels of traffic became paramount and from that emerged the role of the Air Traffic Controller we recognise today.

Major developments in early Air Traffic Control occurred between 1920 and 1922, such that we think of this period as its inception point. Of course it didn’t emerge fully formed, but the intent to aid the safety and efficiency of aircraft was clearly there among those early pioneers. It is one that remains at the heart of what we do today.

Throughout this year and beyond, alongside other industry groups such as Historic Croydon Airport, CANSO, IFATCA, GATCO and Prospect, we are going to celebrate the centenary of those milestones as part of ATC100.

It might be a little unusual to celebrate a centenary over two years, but we hope you’ll permit a little creative ambiguity and join us in recognising the remarkable and often unsung role Air Traffic Control has played in the making of the modern world. Aviation has connected us to places and people in a way that was never thought possible and Air Traffic Control has made, and continues to make, a major contribution to that.

We’ve come a long way in the last 100 years. From a dozen flights a day in 1920, now 2.6 million aircraft are controlled every year by NATS as the UK's main air navigation service provider. But equally, the blueprint laid down in places like Croydon Airport in the 1920s - where the first control tower was built - is still remarkably recognisable. It is only now, 100 years later that things like digital towers and satellite surveillance are re-writing that blueprint and ushering in a new era.

That’s a story that we’ll be exploring this year. Putting a spotlight on the past, the technology and people that made it all possible, while looking to the future and the transformation that’s already underway, the challenges we face and the opportunities.

The birth of Commercial Aviation

Although Germany had begun passenger-carrying Zeppelin operations, followed by a short-lived attempt to use aeroplanes to carry fare-paying passengers in the USA, the start of the first-scheduled commercial air services - between London, Paris and Belgium - had to await the resumption of flying after the First World War in May 1919.

The first commercial aviators, mainly flying in converted bombers, had to confine their activities to flying in ideal conditions, but scheduled operations demanded regularity in all weather. Under the aegis of the newly-formed ICAN (International Commission for Air Navigation and precursor to ICAO) every major airport began sending out and receiving weather reports.

But as demand grew, it became clear a more organised way of safely managing aircraft was essential and so the development of a system of Air Traffic Control began. It was an iterative process, developed by pioneers using the most advanced technology of the day, and all without blueprints or precedent to call upon. And nowhere was that more the case than at the UK's designated primary “air port” in Croydon.

The first control tower

On 25 February 1920, the UK Air Ministry gave approval for the construction of a new building at Croydon, to be ‘erected 15 feet above ground level’ and with ‘large windows to be placed on all four walls’. This building was to be called the ‘Aerodrome Control Tower’ and at a stroke coined both the term that has remained synonymous with Air Traffic Control for the past 100 years and a design that remains instantly recognisable.

The Air Ministry memo that started it all

Airfields before this had had radio offices and aerial lighthouses, but nothing with the explicit intent of providing technical air traffic services to aircraft, in what was described as an ‘essential’ development. Croydon Airport opened in March 1920, taking over from Hounslow as London’s main airport, and the control tower - shown here - was operational later in the year.

The first controllers

The first controllers – known as or Civil Aviation Traffic Officers or CATOs – and the Radio Officers who worked alongside them, provided traffic and weather information to pilots over the radio or via a system of flags or lamps. Croydon also had what was called ‘Direction Finding’ services from 1920 – using radio signals to ascertain an aircraft’s bearing from the airport - while the team there also perfected the more sophisticated system of Wireless Position Fixing, something that was then formally adopted in 1922.

In an age before radar or satellite tracking, Wireless Position Fixing allowed the CATOs to triangulate the location of aircraft via the bearings from three separate radio receivers. The bearings were passed to Croydon where the aircraft’s position was manually calculated and passed back to the pilot. His position could then be plotted on a map with pins, used to chart the course of each arrival and departure. Given radio itself was barely 20 years old, this was absolutely leading-edge technology at the time.

Early Air Routes

As is often the case, it was a disaster that necessitated a change in regulations. On 7 April 1922, a French Farman Goliath and a British de Havilland DH18 collided about 60 miles north of Paris, killing seven people. It was the world’s first mid-air collision and resulted in the adoption of a precursor of the modern airways system.

A Farman Goliath like the one involved in the mid-air collision over France

Pilots on the busy London-Paris air route were instructed to remain west of Ecouen, Abbeville, Etaples and Ashford when flying towards London and east of these landmark towns when flying the route in the opposite direction. Controllers were also given legal authority to instruct pilots – another milestone.

Air Traffic Pioneers

James Jeffs

James “Jimmy” Jeffs, Civil Aviation Traffic Officer at London Croydon Airport, was one of the great innovators in developing the new discipline of Air Traffic Control and went on to have an extraordinary career.

Holder of Air Traffic Control Licence No.1, Jeffs helped developed many of the systems and procedures that were approved by the UK Air Ministry. Having established over twenty-five ATC Units, and the first controller training college, he then led the establishment of the North Atlantic Airspace and the 'track' system that is only now becoming obsolete thanks to real-time satellite surveillance.

By the end of his career in civil and military Air Traffic Control, Jeffs had been awarded the CVO, OBE and the US Legion of Merit.

Jeffs was awarded ATC Licence No.1 in 1953, backdated to his first day at Croydon on 22 February 1922. These ‘little yellow books’ are still awarded to Air Traffic Controllers today.

Fred 'Stanley' Mockford

Another pioneer in those early days, and whose legacy lives on today, is Fred 'Stanley' Mockford.

Moving from Morse Code to radio telephony saw the need for a new way to use language to ensure messages were clearly understood. A railway telegrapher, Mockford served in the Royal Flying Corps during WWI as part of a team developing ground to aircraft communication.

After the war, as Croydon’s Senior Radio Officer, Mockford used that experience to help develop the system of Wireless Position Fixing. Mockford also conceived the distress phrase “Mayday, Mayday, Mayday” in 1923, based on the French word m'aider meaning ‘help me’.

Adopted as the international standard distress phrase in 1927, it still saves lives today.

The re-development of Croydon in the 1920s saw the construction of a second tower in 1923 and a third and final control tower in 1928. The iconic square, white tower - alongside the new airport terminal building - remained in operation until the airport closed in 1959.

Today Croydon Control Tower houses a museum as a lasting monument to the pioneers of the 1920s, the birth of Air Traffic Control and early civil aviation in the UK.

Air Traffic Control: The Early Years

1919 - International convention agreed by 26 countries lays down basis of international aviation and establishes principle of sovereignty of national airspace; International Commission for Air Navigation set up.

May 1919 - UK civil aviation officially resumed after WW1

1919 - Air Navigation Regulations establishes system of 'ground control' under which pilots must seek permission to land with signals to be used; Rules of the Air issued.

1919 – Airlines form International Air Transport Association to represent their interests.

1919 - First scheduled international commercial flight, London Hounslow to Paris by de Havilland DH4 of Aircraft Transport and Travel (AT&T).

1920 - Croydon Airport replaces Hounslow as London's airport; radio telephony stations established at Croydon and Lympne, Kent. French and Belgian authorities follow suit.

1920 - First “Control Tower” is constructed at Croydon

1920 – UK “Aerial Route Traffic Control” procedures implemented with the intent to control air traffic

1921 – Air Ministry promulgates Phonetic Alphabet for aircraft radio communications

1921 - Wireless Position Fixing procedures trialled and calibrated at Croydon

1922 - Wireless Position Fixing promulgated for use for commercial air transport. Position accurate to 2 miles and fix completed in 2 minutes

1922 - First mid-air collision between airliners, killing seven people, leads to system of specific routes for aircraft flying between London and Paris.

1923 - 'MAYDAY' conceived as international signal for aircraft in distress.

1924 - Western Europe linked by international weather reporting system.

1924 - Air Ministry promulgates use of “Mayday” via the Air Navigation Order

1926 - 'Wireless Traffic Control' adopted as title for system of controlling traffic at Croydon by 'control officers.'

1927 - Airliners flying in and out of Croydon required to use wireless and carry a licensed operator

1928 - New Croydon Terminal and Control Tower opened and is the most advanced in the world

1929 - Government warns private pilots without wireless to keep clear of routes used by commercial aircraft in bad weather; pilots using Croydon instructed to use specific routes to avoid annoying local residents.