Looking Down the Corridors

by Kevin Wright

  27 The National Archive: PRO AIR 2/18561: CMS.4123/D.D. OPs. (Recce) B & R 136, 10 January 1963.

  28 The National Archive: PRO AIR 2/18561: MoD Air to RAFG, MoD Signal Message Form, 29 July 1966.

  29 The National Archive: PRO AIR 2/18561: KFM 55569/ops HQ RAFG to MoD AIR, 15 September 1966.

  30 The National Archive: PRO AIR 2/18561, D/365/2/641 AVM Hodges to RAFG, 19 April 1966.

  31 The National Archive: PRO AIR 2/18561, Loose memo, HQ RAFG to MoD AIR, 1 February 1967.

  32 K. Wright (2011), ‘The Photo Pembrokes’, Aircraft, Vol. 44, No. 3, p. 24.

  33 Interview with David Clark.

  34 The National Archive: The National PRO AIR 2/18561, RAFG/TS1247/OPS, 29 January 1962, Para 7e.

  35 Aircrew logbooks are personal documents which record details of aircraft types flown, duration of mission, reason for flight, destinations, etc. They are regularly countersigned by the pilots’/navigators’ commanding officer. Details of security classified or other ‘sensitive’ missions are normally omitted or disguised in some way.

  36 The National Archive: PRO AIR 2/18561, Appendix ‘A’, to HQ RAFG (2nd TAF) Operation Instruction No. 2/62, 29 January 1962.

  37 The National Archive: PRO FO 371/160623, Cabinet Secretary to PM, 1 September 1961, p. 2.

  38 The National Archive: PRO AIR 2/18561, minutes 19 April and 13 June 1962.

  39 The National Archive: PRO AIR 2/18561, minutes 19 April and 13 June 1962.

  40 National Archives: PRO CAB 191/2 ‘The Joint BAOR/RAF Germany Air Reconnaissance Requirement Covering East Germany’, JIC (Germany) (69)24 Final, 31 October 1969, para 6.

  41 K. Wright (2009), ‘Opening the Skies: The Fascinating World of Open Skies Overflights’, Aircraft Illustrated, Vol. 42, No. 5, pp. 60–4.

  42 The National Archive: PRO AIR 20/12133 TS4042/DD Ops(Recce) RAF Doc. 49.

  43 The National Archive: PRO AIR 20/12133, 19 June 1967.

  5

  THE FRENCH CONNECTION: THE ALLIES’ ‘EARS’

  As the Americans and British did, the French Air Force (Armée de l’Air – AdlA), also conducted covert reconnaissance operations along the Berlin Corridors and Baltic coast. They did so in considerable secrecy and, until recently, most of the details remained outside the public domain. Approaches to the French authorities to examine official documents have been unsuccessful. However, in 2009 some participants in these operations produced an account of their experiences in a book, Les avions de Renseignement Électronique, published under the auspices of L’Association Guerrelec.1 This and Hugo Mambour’s extensive and authoritative website, Red Stars over Germany, which covers much detail of the Soviet military presence in the GDR, the AMLMs work and Allied Corridor flights has enabled the assembly of a credible account of AdlA Corridor and BCZ operations.2

  The AdlA used specialist units, aircraft and crews together with dedicated ground stations to collect SIGINT to establish and continually update the Soviets’ and Warsaw Pact’s Electronic Order of Battle (EOB). SIGINT flights made up by far the highest proportion of French missions with photographic flights being of secondary importance. The numbers of AdlA photographic missions were much smaller than those of the British, let alone the United States. The AdlA also expended considerable air effort monitoring the Baltic coast and IGB areas. After 1969 the assets used on Corridor missions were also deployed outside Europe, to support operations and exercises around the Mediterranean and parts of Francophone Africa.

  French SIGINT flights adopted the name ‘Gabriel’, although the origins of its use are unclear. One possibility is that in the French armed forces, Gabriel is the patron saint of signals personnel. It could also be an acronym of the Groupement Aérien de BRouillage et d’Interception ÉLectronique (Air Jamming and Electronic Interception Group) who were responsible for early SIGINT operations. The designators Gabriel I, Gabriel II, etc., refers to the generations of onboard SIGINT equipment, rather than the aircraft type into which it was fitted. Gabriel I–IV referred to the equipment fitted on the C-47, Gabriel V on the Nord N2501 Noratlas and Gabriel VI on the C-160G Transall. Day-to-day operational sorties were frequently referred to as COmmunications ÉLectroniques (Electronic Communications – COMEL) flights.

  French Berlin Corridor operations started in 1957, although the details remain unclear, the main platform for these early Comel flights being the ubiquitous C-47 Dakota. Gabriel I or IV C-47s of Escadrille de Liaison Aérienne 55 (Air Liaison Squadron 55 – ELA 55) flew intelligence missions in the Berlin Corridors from 1957 until the aircraft’s withdrawal in 1963. ELA 55 was based at Lahr-Hugsweier (Lahr) in Germany, alongside the nuclear strike capable F-100 Super Sabres of Escadrons de Chasse 1/3 Navarre and 2/3 Champagne.

  On 1 January 1964 a unit reorganisation transferred the three initial Noratlas Gabriel V aircraft from ELA 55 to Escadrille Électronique 54 (Electronic Squadron 54 – EÉ 54) at Lahr on 31 October 1963. Aircraft and crews now reported to COmmandement du Transport Aérien Militaire (Military Air Transport Command – COTAM). The 1,000th Comel mission milestone was achieved on 14 January 1964, with the 2,000th flight some four years later on 8 November 1968.3

  In August 1964, EÉ 54 was named, following French Air Force tradition, after the commune of Dunkerque in northern France. EÉ 54’s aircraft were distinctive from other units because they generally did not carry unit markings, or codes. The only known exception appears to have been the Noratlas cargo variant, No. 49.

  France’s withdrawal from NATO’s Integrated Command Structure in 1966 caused considerable upheaval amongst its allies. The subsequent departure of US and Canadian forces resulted in significantly reduced intelligence sharing. This was especially noticeable in the co-ordination of activities centred on Berlin. Whilst the Americans and British continued regular intelligence exchange, the French became all but excluded, apart from material covered by the AMLM Tri-Mission agreement.

  Withdrawal from NATO brought significant changes to Corridor flight operations too. The unit moved from Lahr to Metz-Frescaty in north-east France, with a final mission from Lahr on 15 June 1966. The Groupement Électronique 30.450 (Electronic Group 30.450 – GÉ 30.450) and the renamed Escadre Électronique 54 (Electronic Squadron 54 – EÉ 54) moved to Metz, in the same month, flying their first mission on 2 August 1966. On 1 July 1966 GÉ 30.450 had become Groupement Électronique 35.351 (Electronic Group 35.351 – GÉ 35.351), a numbering it retained until becoming the Groupement Électronique Tactique (Tactical Electronic Group 30.341 – GÉT 30.341) on 1 September 1971. Finally it was renamed Escadre Électronique Tactique 54 (Tactical Electronic Wing 54 – EÉT 00.054) on 1 January 1988. That change saw EÉT 54 take control of both airborne and ground-based electronic warfare units. Meanwhile, the Electronic Flight of EÉ 54 was redesignated Escadron Électronique 1/54 (1 Flight/Electronic Squadron 54 – EÉ 1/54).4

  The French military regarded the Gabriel aircraft as a ‘national reconnaissance asset’ rather than a theatre-level one, so they were liable to be deployed elsewhere in the world when wider French interests took priority. Gabriel III C-47s are known to have operated COMINT missions during the 1959 to 1962 Franco-Algerian war but may have been involved earlier. During Algerian operations the aircraft usually carried nine crew members: two pilots, a flight mechanic, a radio navigator, an Arab linguist, three intercept operators and a team leader.5

  N2501 Noratlas Operations

  The arrival of the first Noratlas Gabriel V in late 1962 started the type’s long association with the French Corridor operations, which continued until 1989.6 The first Noratlas modified to Gabriel V configuration appears have been in 1960 but ELA 55 did not receive its first aircraft until autumn 1962, flying its first mission on 29 October. Other modified airframes soon followed. During this transition period, the C-47s probably flew alongside the Noratlas until the latter became fully operational.

  A total of eight Noratlas were eventually modified to Gabriel V standard – Nos 25, 28, 33, 36, 39, 41, 42 and 66. By 1968 seven
were configured for electronic reconnaissance work and the eighth (No. 36) was mainly used to trial the Furet (Ferret) SIGINT systems. The actual number of Gabriel aircraft in the squadron’s service at any one time varied over the years with the addition of a small number of standard transport versions for training and support duties.

  On 1 April 1963, GÉ 30.450 took up residence at Lahr. It was responsible for four fixed ground intercept sites in West Germany that listened to Soviet radio communications and, in conjunction with the Gabriel flights, monitored Soviet and East German VHF/UHF aircraft and ground transmissions.7 Much of the Noratlas equipment was initially US Second World War technology and its limitations soon became apparent. Its relative simplicity and lack of precision meant that it was largely inadequate for the complex operations the Noratlas was called upon to perform. US equipment was soon superseded with that made by French companies CSF, Thomson and Dassault. They produced ‘S’ and ‘X’ band receivers in 1962 for Furet I (Ferret I), ‘L’ and ‘C’ bands in 1964 for Furet II (Ferret II) and 125–1000 MHz equipment for Furet III (Ferret III) in 1967. These programmes produced enhanced receivers that were more suited to the aircraft’s role.8

  Much of the new equipment was frequently installed first on Noratlas No. 36, used as the unit’s flying test bed from 1966 onwards. Initial testing involved the competitive evaluation of prototype Belette (Weasel) and Furet ELINT systems. Weasel was promptly abandoned in favour of the more promising Furet II. In 1969 operational trials were launched from Metz that involved no fewer than fifty flights in one month from Metz along the IGB. After further modifications, a further series of flights took place along the Air Corridors in 1970 and 1971. A 1964 photograph of No. 36 at Berlin-Tegel by photographer Peter Seemann shows that by then it had acquired wingtip pods housing the interferometry antennae of the Ferret III system.9 By 1977 No. 36’s experimental days were largely over and it was converted back to a standard transport aircraft, but the external scars left by the installation and removal of equipment over the years were still clearly visible.

  Whilst the aircraft were primarily configured for SIGINT operations, they were capable of photographic reconnaissance. The earliest camera assembly was fitted to the aircraft’s cabin roof with the lens pointing out of the windows in the rear clamshell cargo doors and looked like something designed by Roland Emmett. This arrangement proved generally unsatisfactory and produced sub-optimal quality, which perhaps explains why photographic missions were regarded as a lower priority. Later, some of EÉ 54’s Noratlas cargo aircraft had cameras mounted on a removable floor cradle that probably used an underside hatch to expose the lens. Noratlas camera configurations included a Omera 40 panoramic camera with a 75mm (3in) lens and a fan of three Omera 36 cameras with 600mm (24in) lens in a three camera installation – one vertical and two oblique – to produce horizon-to-horizon coverage.10 Production of consistently high-quality imagery was not fully resolved until the C-160G Transall entered service in 1989.

  Gabriel V crewing

  The front-end crew of a Noratlas comprised a pilot, co-pilot, engineer and two navigators/radio-navigators from EÉ 54. The mission commander was usually a pilot or radio navigator. The back-end equipment operators, in the cargo hold, came from Groupe Électronique GÉ 30.450.

  The layout in the rear cabin changed over the years but the following provides a representative picture of crew positions. Behind the flight deck on the starboard (right-hand) side was the flight mechanic, adjacent to the externally mounted APU turbine. He was responsible for the APU, the sole power source for all the onboard electronic equipment. The original APU, fitted to the first three aircraft, was a modified Peugeot 403 car engine installed at the rear of the cargo hold. From around 1968 an externally mounted ‘Air Research’ 25 kVA 115 Volt/400 Hz gas turbine replaced the Peugeot APU.11 Before the turbine APU was fitted on Gabriel aircraft, the flight times on each route could be up to an hour longer. The ‘Team Leader’, responsible for all the rear cabin personnel and compiling the mission summary report, sat close to the flight mechanic.

  Two crew positions concentrated on detecting, locating and analysing radar signals in the 50–10,750 MHz range using the AN/ALR 8 equipment. This determined a signal’s relative bearing to the aircraft by using two rotating antennae housed in two black rounded fairings mounted under the fuselage centreline. These were the Gabriel V’s main external distinguishing feature. Two intercept and recording positions monitored VHF transmissions in the 30–300 MHz range using ESM 180 and 300 receivers and a QHAE4A magnetic tape recorder stored the intercepts for further exploitation. One position intercepted and recorded UHF emissions using an ED80 receiver and tape recorder. Another position intercepted MF signals using an NR/AN 8 radio compass and recorder. The ADF receiver would be used to home in on the various VHF beacons located along the air routes and at airports.12 This was the only piece of equipment that did not undergo significant modification over the years, although its analytic and recording interfaces were replaced by French ones compatible with the Smyrne system. One crew position undertook immediate operational analysis of signals.13

  All the positions were manned by trade specialists from GÉ or the Centre d’Exploitation du Renseignement Tactique (Tactical Intelligence Operations Centre – CERT):

  L’Analyse Technique: These men were responsible for intercepting, locating, analysing and identifying all electronic signals originating from Soviet aircraft and ground stations.

  L’Analyse Phonie Graphie: Operators responsible for locating, identifying and analysing transmissions from aircraft and air-related ground stations. They were all linguists who understood the procedures and operational techniques employed by Soviet and East German forces.

  L’Interception: Linguists proficient in Russian, Czech and German with specific knowledge of aviation-related vocabulary who listened in to all air-related transmissions on a wide range of frequencies. The more experienced were able to recognise individual pilots by their voice intonations, even when they used throat microphones.

  Les Intercepteurs Graphie: These operators worked the lower end of the HF band monitoring the Morse networks. They continuously transcribed the stream of information into text for immediate analysis.

  Les Décodurs: ‘Decoders’ de-cyphered tens of metres of teletype printout, looking for Soviet code keys.14

  In addition there was the radio mechanic whose role was to rectify any technical faults with the equipment that developed during the mission. The final crew position was at the rear of the aircraft and was isolated from the rest of the crew by a curtain. This seat was occasionally used by a coder-decoder, photographer or other ‘passengers’, including MMFL members who sometimes used it as an opportunity for intelligence collection on selected targets. The total crew of a Noratlas Gabriel was around seventeen, although this number fluctuated as aircraft equipment fits changed.15

  The long duration and high altitude of Gabriel operations required the fitting of additional specialist equipment to try to improve the crew’s operating environment and almost non-existent comforts. Besides the APU, there was soundproofing and a strengthened cargo floor and all the workstations were fitted with an oxygen outlet. An electric oven was installed to provide hot in-flight meals, managed by the turbine mechanic. Despite the very basic operating conditions, the aircraft engine noise, the permanent turbine whistle when the APU was operating, air turbulence and the need to use portable oxygen equipment when moving around, the operators had considerable success intercepting and translating enemy radio communications.

  The Noratlas, especially in its later years, experienced frequent unserviceabilities, especially engine failures. These frequently caused missions to be aborted and diverted, although no aircraft was ever lost. Because of an engine shortage and the lack of skilled maintenance personnel, it became very difficult to achieve a 70 per cent aircraft availability rate in the 1970s, so maintenance operations were staggered to achieve maximum aircraft availability.16 On one flight, a Nor
atlas returning from a Baltic mission destined for Berlin-Tegel, experienced an engine failure as it approached the entrance to the Northern Corridor. The aircraft commander decided to divert to the West German Luftwaffe base at Wunstorf, near Hannover, and asked the Team Leader to send a coded message to the Metz Command Post advising them of the diversion. The Team Leader delegated the task to a young and inexperienced analyst who informed Metz that the aircraft had a damaged engine and would be making an emergency landing at Wünsdorf, south of Berlin and very close to HQ GSFG itself! The reactions in Metz, HQ Force Aérienne Tactique (Tactical Air Force – FATac) and elsewhere must have been interesting. Whilst nobody probably thought for a moment that the now single-engined aircraft might attempt to land in the GDR, it may have momentarily increased a few heart rates.17

  By 1987, EÉ 54 had only four operational aircraft – Nos 28, 41, 42 and 66. The first to retire was No. 42 in January 1988, followed by the remainder between January and October 1989. The last Noratlas Gabriel V flight by EÉ 1/54 was by No. 66 on 26 October 1989 after twenty-seven years’ service with the unit. It was also the final French Air Force Noratlas flight. By the time of the Noratlas’ withdrawal the whole SIGINT effort involved around 800 people including the flight crews, ground crews, listening station personnel, operations centre and CERT.18

  Mission Planning and Operations

  French Noratlas Corridor operations developed into a well-established routine that started with mission planning. Tasking for individual flights came from the Bureau de Guerre Électronique (Electronic Warfare Office – BGÉ) of the 1st Commandant Aérienne Tactique (1st Tactical Air Command – CATac, later FATac). They planned missions based on data from the CERT. BGÉ sent the orders, including date, timings, route, targets, etc., to the Joint Operations Centres of the GÉ and EÉ at Metz.