by Kevin Wright
The Sixties Peak
Lieutenant Colonel John Bessette USAF (Retired) was a C-97 navigator with secondary intelligence officer duties with the 7499 SG at Wiesbaden from September 1963 until January 1968. As a navigator he carried the responsibility during missions for ensuring that the flight remained within the Corridor airspace or, on peripheral flights, at a sufficient stand-off distance from borders and coasts. Vance Mitchell, also a retired US Air Force Lieutenant Colonel, flew three year periods in both the 1960s and mid 1970s. He too was a navigator in the 7405 SS flying Convair CT-29s and Boeing C-97s on Corridor and BCZ missions from Wiesbaden AB. He later went on to manage the programme at Headquarters USAFE at Ramstein AB for a further two years. Both men’s experiences were during the heyday of CT-29 and C-97 operations. Their observations give a revealing insight into the conduct of operational missions in the 1960s.
Vance Mitchell explained many procedural aspects of the operational missions. Daily activity began at the 7405 SS at about 07.00 when the Intelligence Duty Officer began work on that day’s requirements. As over 400 targets were observable from the Corridors and BCZ, there was always something going on. The more important ones – large troop movements, major training areas, airfields, and the introduction of new military equipment – required coverage ranging from daily to weekly. As Mitchell points out, less important targets were imaged anywhere from monthly to annually:
There were also two types of ‘specials’. The very rare ‘Priority A’ specials required that aircraft launch against them immediately unless safety of flight issues were involved. ‘Priority B’ specials did not mandate launches, but did have precedence over other targets if the mission aircraft flew that Corridor. The Intelligence Duty Officer melded priorities with more routine targets which needed imaging and any last minute intelligence to gain a better understanding of the outstanding requirements.
The result was the day’s target list and thus the Corridors to be flown. If requirements dictated, multiple missions involving as many as four aircraft were mounted. Aircraft commanders could alter the routes into and out of Berlin for reasons of flight safety, usually to avoid severe weather. The main briefing followed at 08.15, involving the whole crew, covering topics such as: aircraft availability, maintenance issues, weather, targets, flight altitudes for best photographic coverage and so on.
Having filed necessary flight plans (including one with the BASC), departures were often between 09.30 and 10.30 hours, though this could be changed for weather or Soviet activities and to suit light angles and seasonal conditions like mist that might affect the target areas. The aircraft, at this time, used their tail numbers as call signs so the Soviets were always aware of which CT-29 or C-97 was approaching the Corridor. Once in the selected Corridor the aircraft would often change course frequently. Whilst this was necessary to capture the selected targets on film, it adversely affected the work of the ELINT operators, who needed good steady courses to be maintained, with minimal changes, to help their equipment perform at its best. So combined sensor missions, with a photographic priority, almost inevitably meant that the quality of the ELINT data collected would suffer.
When ready for departure, the CT-29s taxied to Base Operations to take on any passengers bound for Berlin. The aircraft had a number of airliner-type seats to enhance its cover as a ‘courier’ mission, Mitchell explains:
The four 24-inch vertical and short range oblique cameras and two Special Equipment Operators (SEOs) occupied a tiny compartment in the rear of the aircraft behind a false bulkhead. The SEOs on all aircraft performed in-flight maintenance, activated cameras on command, and changed film magazines.
The flight deck navigator used a ‘modified A-17 viewfinder’ and a remote autopilot to fly a stable line of flight to ensure good-quality photography.33 The key intelligence specialists were the ‘Aircraft Observers’ (AOs), who were frequently PIs, often with a detailed knowledge of some, or all, of the priority targets being covered by the flight. Their task was to look out of the observation blisters on each side of the aircraft for targets of opportunity and any items of special interest.
The C-97s rarely carried passengers on their flights. This left the main deck free for some freight to be positioned, which added a little substance to the ‘regular transport’ cover. Below the main cargo deck was where the real action was happening. For example, C-97 ‘22687’, the most complex of the 7405 SS C-97 fleet, carried a 100in long-range oblique camera, four 24in vertical and short-range oblique cameras, an infrared scanner, and a four-position electronic intercept suite. The cameras and at least three SEOs occupied a relatively spacious below-deck compartment forward of the wings. There were two navigators on the C-97. The forward navigator sat in the window behind either the pilot or co-pilot with a sighting and control device to activate the long-range oblique camera. The radar navigator directed the aircraft and had responsibility for vertical and short-range targets. As in the CT-29s, any crew member could activate cameras to image targets of opportunity. In terms of the non-optical sensors Vance Mitchell explained that:
Electronic Warfare Officers (EWOs) manned the aircraft’s two-position electronic collection suite in a tiny, claustrophobic compartment below the main deck and aft of the wings. Small retractable antennae protruding from the wing and horizontal stabilizer intercepted signals, and a retractable dome, called ‘the tub’, extending below the fuselage, housed the direction finding antenna. The photo mission always had priority, but electronic collection proved valuable enough to remain part of the mission.
He also described for us the steps taken aboard flights to keep the aircraft looking like standard C-97s whenever necessary:
Keeping the real purpose of the aircraft covert required vigilance, cleverly designed systems and good sheet metal work. Whenever a crew member spotted another aircraft in the near vicinity, he would alert the crew to ‘clean up’ the aircraft by saying ‘pull the tub’. That was the signal to retract antennae, close camera doors, and within two seconds make it look externally like any other C-97. Crew members used the same command on all C-97s, whether they had an electronic mission or not. The crew also cleaned up when the aircraft descended below 3,500ft for landing, instead using the command ‘put everything to bed’.
On arrival at Wiesbaden the exposed film was developed to enable a quick intelligence assessment. The photos and electronic intercept tapes were then couriered to the 497 RTG at nearby Schierstein for more complete exploitation.
Following the loss of a T-39 aircraft and an RB-66 in 1964, John Bessette told us that the operating rules for Corridor aircraft became even more cautious, in an attempt to reduce unnecessary losses. Crews were instructed to fly no closer than 4 miles to the Corridors’ edge and no closer than 1 mile from the BCZ boundary.
C-130 Hercules and Rhein-Main AB
Following the rundown of the C-97 fleet in late 1975, 7405 SS moved to Rhein-Main AB and was renamed the 7405 Operations Squadron (7405 OS). By December 1975 it had taken delivery of the first of three highly modified C-130Es under Project Creek Flush for Corridor, BCZ and peripheral missions along the Baltic coast, IGB and Czech–German border. The three aircraft selected for modification (62–1819, 62–1822 and 62–1828) had previously been employed on a covert photographic role in 1966 as part of the Witch Doctor programme. Externally the aircraft looked similar to standard C-130Es but a locked compartment, under the main cargo deck, concealed a single KA-82 panoramic camera that was used on covert missions until 1973.34 In a similar way, Project Rivet Duke was intended to keep the C-130s looking like standard transports, although their equipment fit was much more sophisticated for use in the Corridors and BCZ.
The aircrafts’ large holds were filled with sophisticated and specialised sensors for the 7405 OS mission and the extensive modifications made these C-130s possibly the most expensive ever built (at least until the introduction of the C-130J variants) with an estimated cost of around $75 million (£52.7 million) each at 1986 prices. Besides t
he specialist sensor equipment, the aircraft were also fitted, after 1985, with the wing modifications and Allison T56-A-15 engines of the C-130H. The aircraft were known by a number of designations over the years with C-130E-II being the most commonly used by outside observers; 7405 OS personnel generally referred to them as C-130Es and sometimes after the 1985 upgrade as C-130 Super Es.
Normally only two of the aircraft were with the unit at any one time, with the third being in the USA for deep maintenance, new equipment installation, or updating and repainting. Each aircraft carried cameras and COMINT/ELINT stations to monitor communications and electronic emissions, as well as additional UHF/VHF radios. The equipment fits were similar on each aircraft but never identical. Aircraft were repainted every three years. This was not a matter of military pride, but maintaining the paintwork in the best condition possible was vital in helping to conceal the many sensor doors and hatches that would have been revealed by paintwork in a poor condition. They were also repainted to have their camouflage conform to the standards of the normal airlift C-130s among which they were parked.
There were two optical cameras. The first was a panoramic KA-82 fitted with a 12in lens that used a 2,000ft canister of 5in-wide film producing 24in-long negatives. The camera was mounted aft of the C-130’s nosewheel bay in the area normally occupied by the cargo winch. When the nosewheel was down, its door covered the KA-82’s hatch. The second camera was the KA-81A panoramic camera, fitted with a 48in lens that used a 2,000ft film canister of 5in-wide film, producing 48in-long negatives. The framing settings on this camera could be adjusted to produce shorter negatives. Operated in the oblique mode, it was known as the ‘H-Pan’. It was mounted on a standard C-130 cargo pallet and weighed about one and a half tons. It was frequently referred to as the ‘Big Item’ by the crews.35 The camera was mounted behind the main flight deck area and used a rigid cradle frame that conformed to the fuselage contours. This arrangement allowed the camera to be electrically repositioned to face either the left-hand or the right-hand side of the aircraft as required. On the forward fuselage of cargo C-130Es there are three small circular portholes. In the modified aircraft the middle one was false, being part of a larger, hidden, 18 × 30in door that could be retracted into the aircraft, exposing a 2in-thick optical glass aperture that allowed the ‘Big Item’ to take photographs whilst the aircraft remained pressurised. The KA-81A H-Pan could be set to produce either a 12 per cent or 56 per cent overlap to provide stereoscopic pictures.
Aligned with the leading edge of the wing root and on the aircraft’s underside was an AAD-5 infrared linescan sensor for use at night or in restricted visibility. This was switched on whilst in the Corridors and BCZ to provide a continuous flight record and was regarded as especially important for resolving any later disputes about the aircraft’s position and track. The device was covered by a protective door when not in use.
Very advanced for its time was the Texas Instruments SPF-1 Forward Looking Infra Red (FLIR) mounted in a ball in the rear of the left main undercarriage well. The SPF-1 control panel was situated on the cargo ramps of 62–1819 and 62–1822 and just aft of the ‘Big Item’ on 62–1828. If the aircraft was intercepted by fighters, the co-pilot activated a red toggle switch on the redundant JATO control panel, which retracted the FLIR ball and closed all the ‘secret’ doors in just eight seconds.
The 62–1819 had a large cargo container (24ft long by 8ft wide and 8ft high) with equipment and positions for up to seven personnel. This included the Phase Stability Measurement System (PSMS) and PPMS, made by ITT, developed for the Creek Flea missions many years previously by the CIA. Other positions included two for COMINT collection, two Electronic Warfare Operator (EWO) seats for collecting scientific and technical intelligence and finally a ‘Tactical Co-ordinator’ or ‘Collection Crew Leader’ position. The size of the container required a redesign of the FLIR installation to accommodate it and this became known as Rivet Kit.36 This combination of equipment gave 62–1819 a SIGINT and optical photographic capability, and after further modification in 1980 (Creek Victor) it was capable of verifying Radar Warning Receiver (RWR) performance against Soviet radars and ensuring that the RWR library was as up to date as possible.
The rear troop doors of the aircraft had their secrets too. The two Aerial Observers (AOs) could access a false panel in the doors and replace them with observation blisters and portable seats. This allowed the AOs a much better view out of the aircraft when looking for targets of opportunity. The blisters would be installed just after take-off, as the aircraft climbed, and removed during the descent, immediately before landing when the aircraft was unpressurised.
In May/June 1985, 62–1822 returned from the USA after an extensive overhaul and upgrade. Part of this involved replacing the old KA-81A camera with the new KA-116 Surface Reach Imagery System (SRIS) manufactured by Fairchild Wesson, fitted with a 72in lens. The camera was radically different from the KA-81A. Firstly, it was mounted on a centreline gimbal instead of in the old frame. The camera used three mirrors, each of which was said to cost $1 million (£700,000) at 1986 prices! This combination of optical technology enabled the camera to produce results of extraordinary quality that were regularly at the upper end of the National Image Interpretability Rating Scale (NIIRS), compared to the mid-range scores achieved by the previous cameras. This change significantly improved the squadron’s photographic capabilities.
The PIs also saw the benefits of this radical new sensor. Chris Hughes, a British PI, remembers that the KA-116 SRIS produced excellent imagery that allowed the PI community to look into areas that were normally only accessible to ‘other systems’. An additional, unofficial and very non-PC, use of the system was to image the naturist colonies and beaches along the Wannsee Lake near Berlin. The very high-quality imagery produced some ‘interesting’ results!
During its time in refit the aircraft was given other modifications besides the SRIS. There was a new container that carried the two FLIR positions and an upgraded COMINT collection known as ‘8660’, which was a major advance on the previous equipment. Three EWO positions were dedicated to the collection of Radiation Intelligence (RADINT) – the unintentional electrical radiation emitted by concentrations of cables, power grids and computers – although it is believed that this was not particularly successful. Other equipment installed in the refit included a MIL-STD 1553 data bus, AN/YUK-18 mission recorders, an SKN 2443 dual Inertial Navigation System (INS) and new communications equipment. ‘Dash 15’ engines replaced the earlier models. Inevitably this new configuration led to its redesignation as Rivet Acorn.37
An unintended problem was caused by the mandatory installation and use of in-flight voice recorders, to the whole C-130 fleet. These had to be switched on at all times during flight and presented a particular problem for Berlin operations. When on Corridor missions the circuit breakers were deactivated to prevent the recorders from doing their job. This was done to deny the Soviets any prima facie evidence of their clandestine activities if one of the aircraft crashed or force-landed in the GDR.38
Flying the Corridor with the C-130E
Robert Zoucha joined the USAF in July 1981 at Lackland AFB, where he underwent basic training. After completing his Combat Cameraman course he was assigned to Goodfellow AFB. In 1984, he accepted an assignment to fly with the 7575 OG on Corridor missions in Rhein-Main and he served as an SEO from July 1984 to September 1986 and flew 206 Corridor missions.
During this time the programme was known as Creek Flush, with the imagery known as Creek Misty. The intelligence activities were managed by the 7575 OG, consisting of two squadrons: the 7405 OS operated the aircraft and provided the aircrew, including loadmasters and engineers, and the 7580 OS provided the ‘back-end’ EWOs who operated most of the specialist equipment and the maintenance technicians who repaired the sensors. The programme was surrounded by a great deal of secrecy, even though much of it took place in plain sight on the busy Rhein-Main ramp, which was a combined military airbas
e and civilian airport.
The main external distinguishing feature of the 7405 OS aircraft was a third HF wire antennae that ran from the tail to the fuselage, instead of the usual two on a standard C-130E. The three externally similar 7405 OS aircraft shared the same flight line as the resident 435th Tactical Airlift Wing (435 TAW) C-130s. They were maintained by specially cleared personnel from the 435 Organisational Maintenance Squadron (435 OMS), which allowed them to work on 7405 OS aircraft. Access to the aircraft was limited to those wearing special discreetly marked flight line badges. Additionally, the individual aircraft were kept locked and were fitted with an alarm system that had to be deactivated before entry. The aircraft were closely monitored by the Base Security Forces. Failure to turn the alarm off would see lots of Security Police rapidly descend on the aircraft and, as Robert said, ‘things could turn nasty very quickly’.
Knowledge of the 7405 OS mission was kept very secret at Rhein-Main. As Robert commented, this ‘seemed rather ironic because the Soviets knew exactly what we were doing. We were just keeping it secret from our own people.’ The Base Commander knew the mission they undertook, as did the Chief of Maintenance. ‘The crew chiefs obviously knew our aircraft were different but were expected not to ask questions.’ Similarly, many of the technicians, especially those responsible for some of the special equipment, would have known part of the story too. Passengers were not allowed to fly on the aircraft and special permission had to be obtained for non-crew personnel to fly on the aircraft. This even applied to the 4-star CINCUSAFE, General Donnelly, when he wanted to fly on a Corridor C-130.
