Monday, November 14, 2011

The Dowding System and Information Strategy in the Battle of Britain

Sir Hugh Dowding, the Chief of RAF Fighter Command during the 1940 Battle of Britain faced a critical question, "How to best use the 1,000 fighter aircraft under his command against the much larger Luftwaffe?" He was responsible for the British air defense and knew from WWI that it was rare to find the enemy to engage them. Hoping to stumble on the enemy was futile, because even if the enemy aircrafts' location were known they deliberately changed course to disguise their true bombing targets. Alternatively, the Luftwaffe could overwhelm the RAF with countless flight plans. Improvements in aircraft further complicated matters as speeds exceeded 250 mph, increasing the required speed of communications, analysis, and combat. To counteract his numerical disadvantage Dowding turned to a system which integrated cutting edge communications, information gathering, flight scheduling, target prioritization and interception guidance: The Dowding System.

The Dowding System

Dowding's brainchild was called, "The complex machinery of detection, command and control that ran the battle." Great Britain was on the cutting edge of fighter aircraft design and manufacturing as WWII opened, but armaments, communications and enemy detection were still in their infancy. Dowding oversaw the installation of ground-to-air and air-to-air radios throughout the fighter squadrons, the testing and installation of radar arrays, the creation of a centralized communications system. It is this communications system which I credit with much of the victory.

The first requisition by Dowding on appointment to the fighter squadrons was to quintuple the number of phone lines running into his headquarters. He also fortified these lines against enemy bombing and ordered the creation of a custom made table. It may sound peculiar, but he was creating the first real-time interactive battle plan. The table (shown below) was carved with the outline of the English coast, and was surrounded by volunteer 'plotters'. The plotters would update the battle plan in real time to reflect friendly and enemy aircraft movements that were constantly phoned into headquarters.

Radar supplemented the phone reports, especially given its indifference to cloud cover and its ability to detect planes still over France and the Netherlands. These reports were supplemented yet again by altitude estimates from human spotters, owing to the newly implemented radar's inability to detect altitude.

With this information gathered and processed in this fashion, the plotters could readily provide coordinates, altitudes, and interception courses needed by RAF squadrons while Dowding tried to discern Luftwaffe targets from feints.

Quantitative Methods: Scheduling, Signal Detection, and Target Prediction

  • Maximize Fighter Utilization through Scheduling: Launch fighters so as to maximize time in the air, allowing one British aircraft to fight off multiple waves of enemy aircraft with limited fuel supplies. 
  • Target Prediction: Predict the most likely target using the course and enemy aircraft type data.
  • Interception Calculations: With 500 mph closing speeds for aircraft, enemy course prediction needed to be real time and very accurate.
  • Trigonometry: Dowding created a network of 1,400 trained spotters who used trigonometry to calculate the altitude of enemy aircraft.
  • Signal Detection: Identified aircraft on radar readouts, distinguishing friend from foe and determining the number of aircraft
  • Data Visualization: All radar data, spotter observations, aircraft movements and engagements were plotted in real time (picture below).

Quantification of Benefits

  • "At times, the Dowding System achieved interception rates exceeding 80%." 
  • The invasion of Great Britain (Operation Sea Lion) was postponed indefinitely.
  • The RAF were outnumbered two to one, but they fought off the Luftwaffe. It could therefore be claimed that the Dowding System was a force multiplier that at minimum doubled their strength.
  • Fuel economy: This may seem trivial, but the RAF fighters used 100 octane fuel imported from the United States. It enhanced the performance of the aircraft but it also made fighter fuel a scarce resource to be optimized, so it wasn't feasible to have aircraft on constant patrol. The Dowding System was fuel optimal.


I picked up this book to read over the Thanksgiving holiday without realizing the strategic lessons it would offer. It immediately reminded me  of the quote, "Wars are won by logistics, communications, and battles... in that order" with particular emphasis on the importance of communications. One of Dowding's first acts upon appointment  to lead fighter command was the centralization of communications, the quintupling of the phone lines to that centralized location, reinforcement of those phone lines with concrete to protect them from bombing, and the plotting table. This may seem excessive, but as mentioned in my Cemex blog 'data is the foundation of CAvQM' and communications are the conduit of data delivery.

I was also impressed by the primacy of data collection in the Dowding System. The RAF also needed  fighters that could rival the Luftwaffe, but without a very sophisticated data collection and filtering mechanism they could not have used their RAF fighters effectively. Furthermore, the numerical superiority of the Luftwaffe forced the British to accurately distinguish the important sorties from the diversions.

With Wings Like Eagles: The Battle of Britain. By Michael Korda. Copyright 2009. Harper Publishing.,_1st_Baron_Dowding