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Understanding The Dowding System


A Briefing Paper


The Association of RAF Fighter Control Officers

Footnote Information:
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The story of the Battle of Britain has been told many times by many very capable and distinguished authors and, of course, some less so. The achievements of the fighter pilots - 'the Few', as Churchill dubbed them - is a tale of courage, fortitude and shear tenacity that will endure over time. However, the amazing achievements of the Few have tended to distort the way a battle is usually analysed. It has also tended to mask the contribution of other forces in the battle and especially the system of surveillance and command and control that became known as the Dowding System. This system was highly complex for its day, it reached over vast distances and it conditioned tactics and the way the battle was fought.

Another problem in many accounts of the battle is the fact that they do not always distinguish properly between battle management and combat tactics. Once again the focus of many authors is on how the fighter combat tactics evolved; this is a fascinating and most important aspect of the battle and, of course, it is where either life or death was an immediate outcome. That said, the command and control of the battle was all about how sufficient weapons were brought to bear at the right time and at the right, three-dimensional, place. If this had not been achieved it would have mattered nought about the capability of the Spitfire and Hurricane or the courage and dogged tenacity of the pilots - the battle would have been lost.

The Dowding System provided the commanders at all levels with the tools to manage their part of the battle and its strengths and weaknesses were important conditioning factors on the way the battle was managed. A battle, and especially an extended battle such as the Battle of Britain, is likely to see the enemy change the tactics it uses and the commanders must adapt their response; the pilots may also have to modify air combat tactics in response. In the defensive arena there is a direct linkage between tactical control and combat tactics in that every effort must be made to place fighters in a position that gives them the best tactical advantage to employ their combat tactics and most importantly, to try and surprise the enemy. Surprise is one of the most powerful war winning principles of war. The Dowding System was the instrument of war in Fighter Command’s armoury that denied the enemy the element of surprise and, in turn, enabled the fighter force to surprise the enemy.


There are three things that are necessary for a commander in battle. First, he needs as accurate as possible a picture of what is happening on the battlefield; secondly, he needs to know where his own forces are and, finally, he needs a way of passing orders and instructions to his forces and receiving battle reports from them so that he can control the battle.

In our national history since 1066 there have been four battles the outcome of which was to secure the nation from invasion: The Armada, the Battle of Trafalgar, the Battle of Waterloo and the Battle of Britain.

The first three battles were concentrated in relatively small areas and the eye was the method by which an understanding of the battle could be arrived at and signal flags and riders were the methods by which the battle was controlled.

The threat that faced the United Kingdom in 1940 was vastly different and comprised a numerically superior German Air Force with modern bombers and fighters which could travel at speeds in excess of 200 miles an hour. Moreover, attacks could come from the direction of Norway all the way around to North Eastern France. The rapid development of Radar and Radio Telephony (RT otherwise known as radio) provided the answer and defined a three dimensional battle space of vast proportions.

From 1936 to 1940 the challenge facing Air Chief Marshal Dowding and a small group of scientists and staff officers was, using radar to look far out over the sea approaches to the United Kingdom, how to construct a system that would deliver the three essential ingredients for controlling and winning an air battle anywhere in the battle space. The system they constructed was an amalgam of new technology, processes and procedures, all bound together by a communications network and it was both complex and extensive. The system was subsequently dubbed the Dowding System.

The Dowding System was the first integrated air defence battle management system in the world and the model upon which all others have been based. Not only was the system a compound of emerging technologies, communications, processes and procedures, it also needed people trained to manage and operate the technologies. The system was the instrument by which the Commander-in-Chief and his subordinate commanders were able to look into the battle space and gain an understanding of enemy movements and attacks and then manage, direct and control the air battles. From the outset, it is important to understand that it was an 'elaborate instrument of war' designed both to enable and facilitate command and control in the battle for air supremacy over vast distances in a timely manner.

The first duty of an air force is to win the battle in the air to ensure all other operations and activities can proceed without disruption by enemy air
Lord Tedder

The need for the system was driven by the threat of massive air attacks on the United Kingdom; an exciting brew of new technologies such as radar, radiotelephony and Identification Friend or Foe (IFF) were the enablers for its creation. There had been nothing like it before and there was no model against which military personnel could characterise the system. Hence, the nomenclature used to describe the system frequently failed to capture the true nature of what the system, and parts thereof, was actually doing. This coupled with the cloak of secrecy that was thrown over the system and its enormous complexity by the standards of the times has contributed to the widespread lack of understanding about the importance of the Dowding System and the part it played in delivering victory. Understandably, this, in turn, has led to quite a lot of uncertainty about what the Dowding system actually was.

Modern characterisations of war fighting capability have evolved since World War Two and now provide us with a framework to describe the system in a way that helps to bring its true role and achievements into sharper focus. This short article attempts to do this.

The Components of the System

Air Power has some distinctly different command and control imperatives to those of the other armed forces but the elements of 'generalship' needed to fight a fast moving and dynamic battle for air supremacy resonate strongly with the needs of army and naval commanders fighting tactical battles in their respective environments. Arguably the most important common factor is the need for a clear and unambiguous real time picture of the battle space. The gathering of information to service this need is characterised as Intelligence, Surveillance, Target Acquisition and Reconnaissance (ISTAR); the term actually does not distinguish between the strategic and tactical military need for information. Within most Orders of Battle (OOB) the force element that has to deliver 'ISTAR' is usually a distinct force element in its own right. The real-time requirement to produce a tactical air picture is provided by surveillance and, within the emerging system of air defence in the late 1930s, this element, which was characterised by the singularly inappropriate term Raid Reporting, was subsumed within the boundaries of the Dowding System itself. Like all ISTAR outputs there is a need for the raw data to be processed to produce a coherent and understandable product. In air defence terms this is now called a Recognised Air Picture (RAP) and, at the time, the process to arrive at this picture was called filtering. The Filter Centre was the master 'cog' which drove all the other 'cogs' in the system.

Command and Control (C2) are human functions and all fighting military forces have one commander and subordinate commanders at various levels, whose actions are limited by span of control and delegated responsibility, to deliver a military output to meet a military aim. Although the exercise of command and control is a human function delivering it is technology dependent and the technology that delivers a system to enable C2 is, in modern terms, unsurprisingly known as a C2 System. The rapid transmission of information necessary to prosecute a modern battle requires extensive communications and the complete dependence on communications has expanded the system definition to become a Command, Control and Communications (C3) system. The Dowding System was the progenitor of modern C3 systems.

The Fighter Command command and control ethos was characterised as centralised command and de-centralised control and it was implemented through a three level structure. Full command of all RAF assets and operational command of Anti-Aircraft Artillery (AAA) and the Observer Corps was exercised by the Commander-in-Chief. Group commanders and AAA Divisional commanders exercised operational control. At the lowest level of C2, Sector commanders and Battery commanders exercised tactical control.

From the foregoing it can be seen that the Dowding System was a combination of surveillance sensors, a recognised air picture compilation process and a C3 system used to manage and control all the weapon systems within the Order of Battle (OOB). The weapons are not part of the system per se and this is where there is often confusion between the OOB and the system of C3.

Recognised Air Picture Compilation

Figure 1 - The Recognised Air Picture

Radar was the technology upon which the system was built; it provided the warning necessary for commanders to organise a balanced tactical response to air attacks against the UK. However, it was not the complete answer. In the early days of the development of the system, radar installations only really looked out to sea from the coast and, therefore, another sensor system was required over land and this was the eyes of the Observer Corps. In summary, the two raw surveillance sensor systems were radar and the human eye and brain. The raw radar data was sent to a Filter Centre which analysed the information, removed anomalies and merged data to produce track information, in three dimensions; this was then uniquely referenced, identified and categorised. The overland reports emanating from observer posts were passed to Observer Group centres where the information was sorted to produce a coherent report. Because of time pressures the information from Observer Groups was initially passed directly to Sector headquarters. However, as radar coverage overland improved and the filtering process was de-centralised to Group headquarters the Observer information was passed directly to the Filter centres for processing into the air picture. Nonetheless, even in the early days, Observer reports had to be cued by a radar track; this meant that the Observer Group could not initiate new tracks overland that had not been previously built, referenced and recognised by the Filter centre.

Command, Control and Communications

The Commander-in-Chief (C-in-C) of Fighter Command exercised full command of all RAF forces allocated to his Order of Battle and Operational Command of the Anti-Aircraft Artillery and the Observer Corps. Full and operational command entails much more than just the management of forces in battle. For air battle management the C-in-C exercised command through an operations centre. This concept was flowed down to Group and Sector commanders who exercised operational and tactical control respectively through operations centres. These centres were all provided with the recognised air picture covering their area of responsibility. The AAA system was similarly served with an air picture and gun control and cueing flowed through Brigade Operations centres to Gun Operations Centres (GOC). The Sector headquarters was the only echelon within the C2 structure that talked directly to the fighter aircraft during early development of the system. From early 1941 an increasing number of Ground Controlled Interception (GCI) radar units joined the line and they also communicated directly with aircraft.

Figure 2 - Command and Control

Fighter Command was vast in both terms of geographical spread and resources that comprised the complete Order of Battle. All elements had to be brought together into a unified whole and to do this they had to both receive and disseminate information and orders and this required an extensive network of ground to ground communications, which was installed and managed by the General Post Office (GPO). The role of the GPO is all too frequently glossed over but the work it did in building a widely dispersed and complex network of ground communications, rapidly adapting the network and maintaining and repairing it often as a result of battle damage was a major feat in its own right and a story that needs to be told. The GPO also provided terminal equipment such as keyboards, Headset sockets, headsets and timing devices necessary for the system to function effectively. Where time permitted, a Wireless Telegraphy (WT) system was used to pass information and there was also a comprehensive ground to air Radio Telephony (RT) communications system which operated both in the High Frequency (HF) and Very High Frequency (VHF) bandwidths. The RT system was also used to triangulate the position of fighters to provide a ‘fix’ for battle management purposes and to help pilots to navigate and maintain station if they were on a combat air patrol flying a fixed circuit.

The System

The Dowding System was both a Surveillance and C3 system and it evolved as the war progressed and as lessons were learned, but the fundamentals did not change - they were just adapted to meet changing circumstances and one of the inherent strengths of the system was that it could be readily adapted to meet changing circumstances. The most obvious way this was demonstrated was the way the system was reconfigured to deal with attacks from unmanned aircraft - the V1 - and ballistic missiles - the V2. From the pictures above it can be seen that the system had two clearly bounded elements that were wholly inter-dependent. There is no better way than to let the words of Churchill sum up the importance of the system to victory in the air over the United Kingdom.

"All the ascendancy of the Hurricanes and Spitfires would have been fruitless but for this system which had been devised and built before the war. It had been shaped and refined in constant action, and all was now fused together into a most elaborate instrument of war, the like of which existed nowhere in the world"

Winston Churchill, The Second World War, Volume 2, 1949