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The Start of Commercial Aviation - 1919-1929

Although Germany had begun passenger-carrying operations by Zeppelin airships, 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 and Paris – had to await the resumption of flying after the first world war.

The first aviators had confined 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) every major airport began sending out and receiving weather reports.

A mid-air collision in 1922 near Paris between a British and a French airliner resulted in the adoption of a precursor of the airways system.

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.

Many aviators navigated by following railway lines and station names were painted on roofs to help them. Soon, all commercial aircraft were required to carry wireless and there were further experiments with radio direction finding and ‘air-light’ beacons.

But at London’s newly-opened airport of Croydon, plotting the position of aircraft was still in its rudimentary stages using a map pasted on a board with lengths of string; the point where the strings crossed was the aircraft’s position.

Radio direction finding equipment was installed there and at Pulham in Norfolk and radio transmitting and receiving stations were opened in both Britain and Europe.

When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return.

Leonardo da Vinci

Key Dates


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.

UK civil aviation officially resumed after WW1.

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.

Airlines form International Air Transport Association to represent their interests.

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


Latitude: 51° 21’ 13.78” N
Longitude: 0° 07’ 1.45” E

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


First “Control Tower” is constructed at Croydon

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


Air Ministry promulgates Phonetic Alphabet for aircraft radio communications

Wireless Position Fixing procedures trialled and calibrated at Croydon


Jimmy Jeffs begins work at Croydon Airport as a Civil Aviation Traffic Officer

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

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

James 'Jimmy' Jeffs



Conceived as international signal for aircraft in distress.



Gathering Pace

Technological developments helped to improve the safety of flying especially at night and in poor visibility. In the USA, where mail flights were being made in all weathers and over long distances, a network of radio beacons transmitting signals to help pilots find their way was under development. It would lead to the creation of ‘airways’.

Aircraft instrumentation improved and Germany introduced the Lorenz radio-beam blind approach landing aid, the use of which spread throughout Europe.

Meantime in Britain a system of light signals was developed to maintain safety of aerodrome operations, but demands for a more systematic form of air traffic control were growing both at home and abroad. Yet despite having Europe’s most a rigid form of air traffic control Germany suffered two mid-air collisions in 1936. There were none in Britain.

Key Dates


First radio beacon installed at Croydon.


Traffic density at Croydon results in the UK’s first Aerodrome Control Zone and adoption of specific procedures to maintain safe separation between aircraft.


IATA calls for standardised system of aircraft landing aids.

Most of Britain’s 27 municipal airports now equipped with wireless and maintain some form of control for aircraft using them.


Lorenz blind approach landing equipment installed at Croydon.


First training school for ‘air traffic control officers’ set up by Jimmy Jeffs and approved by Ministry of Aviation; Ministry opens its own school a year later.


Government-appointed Maybury Committee calls for a ‘comprehensive air traffic control organisation adequate to ensure the safety and regularity of air communications.’


Division of airspace into two categories, aerodrome and area, proposed.


Air Ministry officially adopts term Air Traffic Control.

There’s more to life than being a passenger. Never interrupt someone doing what you said couldn’t be done.

Amelia Earhart


First radio beacon installed at Croydon




The Impetus of War

Worried about Britain’s vulnerability to aerial attack and Prime Minister Stanley Baldwin’s assertion that ‘the bomber will always get through,’ the Government appointed a committee of scientists to find a defence.

Quickly rejecting the idea of ‘death rays’ to disable attacking aircraft the committee moved on to consider their detection by the transmission of radio waves.

This was ultimately to lead to the development of radar, which was not only to be crucial to national defence in the coming war but was later to put a vital tool in the hands of air traffic controllers.

The impetus of war lead to further technological advances in the identification of aircraft, in navigation and target finding, all of which were later applied to air navigation and air traffic control. At the same time, aircraft were becoming more reliable and able to carry larger payloads over greater distances than ever before.

We shall fight with growing confidence and growing strength in the air, we shall defend our island, whatever the cost may be. We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender.

Winston Churchill

Key Dates


Drawing upon earlier work in Britain and Germany, Robert Watson Watt submits memorandum to committee on The Detection and Location of Aircraft by Radio Methods, which will later be acknowledged as marking birth of radar.


Government sets up Chain Home network of radar detection stations along Britain’s east coast; will play a vital role in the nation’s defence in the coming war.


Luftwaffe uses radio beams to find targets in night attacks on British cities.

British scientists develop resonant cavity magnetron, leading to greater concentration of power in reduced wavelengths and radar sets small enough for aircraft use.


Gee equipment, using intersecting radio beams transmitted by ground stations, enables 80 per cent of attacking force to find target in RAF1,000 bomber raid
on Cologne.


RAF pathfinder force uses starts using OBOE blind- bombing aid.


US-developed LORAN system improves navigation and position finding on north Atlantic; later extends to Europe and Far East as war progresses.


RAF opens flying control centres at Uxbridge, Gloucester, Watnall, Preston, Prestwick and Inverness to provide ATC services to aircraft flying over UK; will form the basis of post-war civilian ATC system.

1943 H2S radar equipment enables RAF crews to pin-point targets with greater accuracy.



RAF ATCHQ established at Uxbridge.

Even before the war was over, representatives of the allied nations were again meeting to set rules for commercial aviation in what was expected to be an era of growth encouraged by the use of newly-developed technology.

The resulting Chicago Convention and the Standards and Recommended Practices contained in a series of annexes lay down rules on every aspect of civil aviation including (in Annex 11) the development and conduct of air navigation and air traffic control.

This forms the basis of present day ATC throughout the world.

A network of control centres based on the RAF’s war-time defensive system was quickly established. But despite its early lead in the development of radar, Britain lagged behind the USA in applying the new technology to civilian use. The US was already well on the way to establishing a system of airways, essentially aerial highways ten miles wide and extending upwards from 3,000 feet and marked by regular radio range beacons. The UK, meanwhile, was making good use of the comprehensive network of 53 beacons installed by the US forces during the war. And from a study of US methods emerged the beginnings of the airways system in the UK in 1951 when the first airway Green One was swiftly followed by Amber One running up the middle of England to Prestwick and then to the Solway Firth. The Manchester Control Zone was set up and Airways Green Two and Red Three, for flights to Dublin and Belfast, were created.

The Ground Controlled Approach (GCA) system, in which a team of controllers using radar (initially installed in a caravan at the end of the runway) vectored incoming aircraft to a safe approach and landing in all weathers, also originated in the USA. GCA led on to Precision Approach Radar, later replaced by today’s Instrument Landing System (ILS). Other war-time inventions also had valuable peace- time applications. The Chain Home network of air defence radar stations, which had played so crucial a role in the Battle of Britain, formed the basis of a civilian ATC system. In fact, the last of the military installations was not superseded by new equipment until the 1970s. During the 1950s, the wartime Identification Friend or Foe (IFF) was developed into Secondary Surveillance Radar (SSR). This meant that by transmitting a signal from the ground, controllers could interrogate an aircraft’s transponder and receive valuable information about its height, route and callsign.

Give me the third best technology. The second best won’t be ready in time. The best will never be ready.

Sir Robert Alexander Watson-Watt

Key Dates


52 nations meet to consider needs of post-war commercial aviation with a framework contained in Chicago Agreement and subsequent annexes; by year’s end, outline of an international air traffic control system has been drawn up.

Construction starts on new airport at Hounslow Heath, later to become Heathrow


Government establishes post-war system of ATC with specified flight safety regions, control areas and control zones within which aircraft are required to conform to laid- down procedures, especially in poor visibility.

Creation of Metropolitan Control Zone, covering area “within 24-mile radius of Westminster Bridge London, equipped with non-directional beacons enabling pilots to fix positions and report to controllers.


First Ground Controlled Approach (GCA) radar equipment installed at Heathrow and Prestwick.

UK airspace divided into five flight information regions (FIRs) each with its own control centre: south eastern (Uxbridge), south western (Gloucester), northern (Preston), central Scotland (Prestwick) and northern Scotland (Inverness).


Control zones established within eight miles of major airports.


Airlines call on Government to improve UK ATC with a ‘corridor system of control,’ similar to the US airways.

Senior British air traffic controllers visit Chicago to study US ATC operations.


London Radar becomes operational Heathrow.

Green One, Europe’s first airway opens, running from Woodley near Reading to Strumble Head on the Welsh coast.


Five new airways created: Amber One- Daventry- Dunsfold-Dieppe-Paris; Amber Two – Daventry-Brookmans Park-Maidstone-Paris; Blue One – Woburn-Watford- Crowborough; Red One – Dunsfold-Maidstone-North Foreland-Amsterdam; and Red Two- Woodley-Epsom- Ashford. Government considers use of computers for processing flight plan data.


Plans announced for Gatwick to become London’s second airport.


Southern Air Traffic Control Centre moves from Uxbridge (where it had been known as London Airways Centre) to Heathrow.


Re-developed Gatwick opens.


Croydon Airport closes.



Growing Pains

Steadily increasing air traffic, spurred on by the development of the inclusive tour holiday market, caused further headaches for successive governments. Inside 15 years, traffic grew from a million passengers a year to 15 million. The ensuing debate about the need for more airport capacity for the London area dominated headlines during the 1960s and 1970s.

This overshadowed the need to modernise the nation’s ATC system, which was just as pressing. As a result a new ATC radar system known as Mediator emerged and with its supporting flight data processing system was operational by the early 1970s. Mediator had originated as the civil spin-off from the Linesman equipment developed for national defence. To run Britain’s ATC a new unified civil-military operation was formed outside direct government control.

The new organisation inherited the task of providing a guaranteed route structure for commercial air traffic while maintaining maximum flexibility for every sort of flying outside that route structure. Only about three per cent of the airspace was actually controlled airspace, which included airport terminal areas and the airways (between 5,000 feet to 24,500 feet) for airline traffic. Aircraft flying in controlled airspace were subject to ATC instructions and obliged to carry specified navigation and communications equipment.



By the end of 1971 Britain had A combined total of 150 radar displays presenting basic information for the tactical control of air traffic a network of ten civil radar stations and seven joint civil/military units, equipped with primary and secondary radars.

  • 59 Non-directional beacons (NDBs) with another 20 ‘ specifically en-route non-directional beacons.
  • 42 VHF omni-directional ranges (VORs) including one Doppler VOR.
  • 25 Beacons with distance measuring equipment.
  • Four control centres: West Drayton, Preston, Prestwick and Oceanic, also at Prestwick, handling trans-Atlantic traffic.
  • 14 airport radars.
  • 45 Radio stations providing voice communications between pilots and controllers using 150 VHF and 75 UHF radio channels.
  • 200 Civil and military controllers at centres and airports.

I need a High Intensity Runway Operations

Key Dates


Government gives go-ahead for Linesman/Mediator military-civil radar system.

National Air Traffic Control Planning Group, also known as the Patch Report, recommends unified civil- military organisation to run Britain’s ATC.


Government announces formation of National Air Traffic Control Services (later National Air Traffic services – NATS) to operate under a controller reporting to Ministry of Aviation and Secretary of State for Air.

RAF West Drayton designated as site of civil-military air traffic control centre for southern England.


First Scottish area control radar operational at Gailes on the Ayrshire coast; other will follow at Renfrew and Prestwick.


Technical specification issued to industry for development of flight planning system.


Stansted designated London’s third airport after three-year study despite being rejected by public inquiry.


Edwards Committee on future of UK airline industry recommends formation of separate civil aviation authority to act as regulator and operate ATC


London Air Traffic Control Centre (LATCC) operational at West Drayton; new civil sector suites introduced under Mediator programme.


Civil Aviation Authority formed with NATS reporting jointly ‘to its chairman and the Chief of the Air Staff.

British European Airways (BEA) Trident makes first ‘blind’ (Category 3A) landing at Heathrow; CAAorders 23 ILS systems of Category 2 (400 metre runway visual range) or Category 3A standard.

Scottish and Oceanic centres move to Atlantic House, Prestwick.


Mediator programme completed with closure of Preston Control Centre and duties assumed jointly by West Drayton and Manchester Sub-Centre; London Flight Information region formed covering whole of England and Wales.

Flight data processing system in operation at LATCC using IBM9020D computer equipment.

SSR code to callsign conversion system introduced at LATCC to convert aircraft transponder signals to callsign or flight number on-screen display.


NATS’ first off-shore radio station opens in North Sea


New Scottish Air Traffic Control Centre opens at Prestwick with UK’s first fully processed radar system receiving information from five sites.

70 years of UK air traffic



The Building Blocks

Far-reaching decisions on the ownership of British Airways and the nation’s major airports were taken by the Thatcher government. The thorny question of airport development in the south east of England, too, was settled, at least for a while.

But lack of concerted action and investment in air traffic control infrastructure, both in the UK and Europe, made itself felt in the late 1980s.

A series of delays at major airports during the peak summer season was a consequence of sharp traffic increases fuelled by strong economic growth. The problem moved swiftly up the political agenda and as it did so the scale of the problem became clear.

European air traffic control was based on a multiplicity of different national systems using a variety of equipment, often incompatible with one another. Concerted action, focused on a number of pan-European harmonisation programmes run by Eurocontrol, followed.

The CAA’s response was a comprehensive nationwide programme to up-date the nation’s en route and airport ATC systems. Planning also began on a complex re- organisation of air traffic management in the south-east in anticipation of increases in airport capacity. But the biggest and most ambitious proposal was for a brand new air traffic control centre for handling traffic flying over England and Wales.

Key Dates


NATS starts airport radar replacement programme.


Monopolies and Mergers Commission (MMC) publishes report on UK air traffic control praising NATS’ high safety standards but making 49 recommendations for cost reduction and efficiency improvement.


NATS starts planning for new air traffic management system for south east England.


One million movements handled by controllers in London FIR for the first time in a year.


Doppler VOR navigational beacon programme complete.

Sixth new radar station at Great Dun Fell completes en route radar replacement programme.


European Central Flow Management Unit established at Brussels by Eurocontrol.


European Central Flow Management Unit established at Brussels by Eurocontrol.



Towards the New Millennium

The UK’s response to the deficiencies of the air traffic system so graphically demonstrated in the late 1980s was both swift and re-assuring: a major investment programme worth around £100 million a year at its peak in the early to mid 1990s.

By then, much of the UK’s ATC infrastructure had been comprehensively up-dated and in 1995 the highly complex Central Control Function project was successfully completed with the seamless transfer of airport approach control to the new terminal control room at LATCC.

Key Dates


Work starts on construction of new air traffic control centre at Swanwick, Hampshire


NATS airport primary radar replacement programme completed.


Terminal control room opens at LATCC with move of Heathrow and Gatwick approach controllers.

Opening of re-developed Manchester Area Control Centre


Government announces plans to privatise NATS.

Swanwick Centre building complete and handed over to CAA


Central Control Function project completed with move of Stansted approach control to LATCC Terminal Control Room.


London Flow Management Unit closes with establishment of Central Flow Management Unit at Brussels.


New Labour Government says it wants to make NATS a public private partnership and separate it from the CAA.


Government and NATS announce that Swanwick will open in the winter of 2001/2002.


Government gives go-ahead for preliminary stage of New Scottish Centre but abandons Public Finance Initiative.

Transport Bill, providing for NATS to become a public private partnership, introduced to Parliament.

Air traffic control centre at Swanwick, Hampshire




The Public-Private Partnership for NATS was proposed in June 1998, and enshrined in the Transport Act 2000.

The Government chose the Airline Group as the preferred partner in March 2001 and the transaction was completed in July 2001 with the sale of 46% to the AG and the devise of 5% to staff. Although the Government retained the balance, the company was free of Treasury control.

The aviation industry downturn after 11 September 2001 led to a financial restructuring of NATS. This involved £130 million of additional investment (split between Government and LHR Airports Limited) to reduce borrowings. At the same time, LHR Limited took a 4% shareholding, reducing the Airline Group’s holding to 42%. A £600 million bond issue, successfully completed in October 2003, further reduced NATS’ debt.

In 2003, NATS launched its ten-year £1 billion investment programme with the announcement of a complete renewal of its radar network. NATS then became the first in Europe to establish a working Functional Airspace Block (FAB) with Irish counterparts; and launched a Joint Venture company with the Spanish to develop the next generation of air traffic management systems for Europe.



NATS becomes a Private Public Partnership


9/11 results in a 15% drop in trans-Atlantic traffic


Last commercial Concorde flight [see flight strip photo in G Drive link]


London Terminal Control moved from West Drayton to Swanwick Centre


The new Prestwick Centre opens


Icelandic volcano Eyjafjallajökull erupts spreading ash over northern Europe and bringing air travel to a halt for six days


NATS develops iFACTS, technology that can predict aircraft trajectories 18 minutes in advance


NATS introduces an environmental improvement programme, including 3Di, the world’s first flight efficiency index


Time Based Separation – a world first – it deployed in London Terminal Control for Heathrow arrivals and cuts head wind related delays by 62%


NATS launches its Deploying SESAR programme to being introducing the next generation of air traffic management technologies. London Area Control moves into a temporary operations room at Swanwick


Airspace changes are introduced for London City and Stansted airports as part of longer-term plans to redesign and modernise UK airspace for the first time in 60 years


The next generations flight data processing system, iTEC is deployed at Prestwick as part of the Deploying SESAR programme


NATS takes a 50% stake in the digital tower and artificial intelligence company, Searidge Technologies


Electronic flight strips replace paper in London Terminal Control meaning all UK en-route ATC is now paperless


Aireon’s real-time satellite surveillance is introduced over the North Atlantic by NATS and NAV CANADA in what was a world first


Busiest ever day in UK airspace with 8,863 flights


100th anniversary of the opening of the world’s first ‘Aerodrome Control Tower’ at London Croydon Airport


The COVID-19 pandemic sees up to a 90% fall in air traffic

Celebrating The Birth of Air Traffic Control 100 Years