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A Briefing Paper


The Association of RAF Fighter Control Officers

The D-Day Fighter Control Story

Compiled and Edited
Group Captain Tim Willbond RAF (Retd)


This paper has been compiled from a number of sources. Squadron Leader Mike Dean and Mr Peter Best generously provided information and advice and a special debt is owed to Doctor Les Dobinson for his advice and contribution which was special because he was there. Some facts have been taken from Government sources and under the terms of the standard Open Government Licence we would like to acknowledge the importance of Air Publications 1063, 3237 and 1116 that were produced by the Air Historical Branch in the 1950s

This document is not for sale and has been compiled for use by the Association of RAF Fighter Control Officers and the RAF. The document may be used for wider research purposes but material contained herein may not be reproduced without the approval of the providers of the source material.

Fighter Control During the Assault Phase of Operation Neptune - 6th June 1944


By 1944 there was a wider understanding amongst the air planners that control of the air was a primary responsibility for the air force. Experience gained in the Battle of Britain, the Western Desert and Mediterranean had shown that success in controlling the air was dependent upon a system of command and control that used radar to provide warning of attack and a tactical picture of the airspace for battle management and weapons control. Surveillance using radar prevented the enemy air mounting surprise attacks and with intelligent battle management could be used to surprise the enemy. Moreover, the lessons from the North Africa had also shown the value of radar cover beyond the front line to help both direct and protect offensive air operations.

The section of the French Coast selected for Operation Neptune, which was the code name for the assault phase for the liberation of Europe otherwise generally known as D- Day, was over 80 miles from the English coast. South coast radar units could provide some cover over the beaches but the advanced warning of enemy air approaching the beaches was insufficient to ensure control of the air. It was necessary, therefore, to extend the coverage for both picture compilation and tactical control and to establish ashore, at the earliest possible time, mobile tactical air control units to control and defend the air above the bridgehead.

Once again experience from the Mediterranean, especially Operation Husky, the invasion of Sicily, had thrown up many valuable lessons one of these was that units providing control of the air and the control of offensive operations as part of a composite RAF Group working alongside the advanced elements of the Army could not also provide picture compilation and the control of day and night fighters in the base areas and behind the front line.

Another lesson was that picture compilation, which included the track analysis (known as filtering) and the track identification processes, should be collocated with the composite Groups’ operations centres and so these two operational capabilities were combined into one Group Control Centre (GCC). Prior to this the picture had been constructed and maintained by a separate Mobile Raid Reporting Unit (MRRU).

Air Organisation for Operation Neptune and Overlord

All RAF and US air forces assigned to operation Overlord – the liberation of Europe - were placed under the command of the Commander-in-Chief Allied Expeditionary Air Force (AEAF) with the RAF managing all air operations in the British area of responsibility and the USAAF managing air operations in the US area of responsibility.

In the UK area the plan was that No 85 Group would provide air defence behind the front line and especially all the base areas. The Second Tactical Air Force (2ATAF) was to prosecute the forward air battle including close air support to the army and it comprised two composite Fighter and Fighter Bombers Groups, Numbers 83 and 84 Groups, and a Medium Bomber Group - No 2 Group. Surveillance and control units providing air surveillance and tactical control were assigned to Numbers 83 and 84 Groups.

Figure 1 - AEAF Organisation

Generally speaking, No 83 Group worked with the Second British Army and No 84 group worked with the First Canadian Army.

The forward battle was fluid and control of both offensive and defensive air did not lend itself to the structure that had been established for the defence of UK airspace. However, the defence of the base areas was modelled more on the UK system and under the Group Commander three base Defence Sectors were established. The organisation is shown at Figure 1.


Operation Neptune

Operation Neptune covered the assault phase and was all about establishing a firm bridgehead ashore by D-Day plus 1. The responsibility for the defence of the air for Neptune was vested in the Commander-in-Chief of Air Defence of Great Britain (ADGB), formally Fighter Command, which was based at RAF Bentley Priory. The AOC in C delegated the operational control of air forces to undertake the task to AOC 11 Group. The challenge for the air surveillance and control system was to provide adequate forward cover and the seamless transfer of control of the air to 85 Group units; this group was to deploy the first tactical control units over the beaches.

Figure 2 - FDT Filter Table
Courtesy of Mike Dean

The plan that was formulated required a total of 3 Landing Ships Tank (LST) to be converted as air surveillance and control ships; these were designated as Fighter Direction Tenders (FDT). The interesting point is that the FDTs, in addition to early warning and control, also undertook the full picture compilation role with their own Filter Centres and Identification teams. A picture of a Filter Centre in a FDT is shown at Figure 2. The FDTs were Royal Navy units under the command of the Allied Naval Commander of the expeditionary naval forces but were operationally controlled by AOC 11 Group.

Figure 3 - Type 15 Aerial on a FDT
Courtesy of Mike Dean

Figure 4 - FDT 217

The concept of using ship borne RAF radar equipment for surveillance and control was first trialled in North Africa and then used during Operation Husky when LST 305 was fitted with Ground Control Interception (GCI) radar (the Type 8 then used by GCI units in the Mediterranean at the time), control equipment and radios. The D-Day FDTs were equipped with the Type 15 and the Type 11 radars both fitted with Mark III IFF interrogators/responders, Aircraft Interception beacons and VHF radio telephony and wireless telegraphy sets. The term GCI was a rather interchangeable term that was used to denote radars that could be used for close controlled interceptions but also for those which were primarily control units although they also had an early warning and surveillance role. The FDT system proved so successful the AOC-in-C Fighter Command pressed for 4 FDTs to support Operation Neptune. Three were produced:

Figure 5 - FDT 13

  • No 216 FDT. This FDT was positioned seaward of the US beaches in the western half of the assault area. Its role was to produce a tactical picture over the US area, provide raid reporting and to control both RAF and USAAF fighters tasked to operate in the area.

  • No 217 FDT. This FDT was positioned seaward of the British beaches in the eastern half of the assault area to undertake the same role as FDT 216. However the ship was designated as the main coordinating FDT or Master Control FDT; the senior RAF controller was aboard this ship. The Master Control FDT had the additional role of managing fighter resources across the whole assault area.

  • No 13 FDT. This FDT was positioned in the main shipping route to provide defensive cover over the shipping lanes.

The FDT positioning in relation to the air corridors, shipping lanes and assault beaches is shown at Figure 6 below.