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Gary Parsons goes behind the scenes at the North Sea ACMI range at RAF Waddington for Exercise NOMAD, held over 9-25 July 2001.

A variety of different nations once again descended on Waddington in July for the annual Exercise 'NOMAD', the largest Dissimilar Air Combat Training (DACT) exercise in Europe. Centred on BAE Systems' North Sea ACMI Range, Air-Scene UK was invited to see what goes on behind the scenes.

What is ACMI?

The North Sea ACMI Range (NSAR) is centred some eighty miles off England's east coast in dedicated air combat training airspace. It has been cleared for use by a wide range of NATO and European fighters and uses the latest technology to provide a very high degree of accuracy in the measurement of user aircraft position and flight conditions, together with simulation of missile firings and the outcome of tactical engagements. Known by its 'Showground' callsign or simply as the 'ACMI', the main control centre and debriefing facilities are at RAF Waddington in Lincolnshire.

The North Sea ACMI facility is based upon an American system, BAE Systems (then British Aerospace) having bought it from Cubic Worldwide Technical Services (CWS) under a Foreign Military Sales licence in 1988. Constructed during 1988/89 as a private venture that cost approximately £60million, the original concept of the range was to fill a gap in air combat training that had been identified by the company within the European theatre. BAE SYSTEMS' concept was to make the NSAR financially profitable by selling thirty-minute range 'slots' to any airforce that might want to use the facility to conduct air-combat. Current customers include UK MoD (RAF, RN, QinetiQ), Netherlands, USAFE, France, Belgium, Switzerland, Austria, Spain, Denmark and Norway.

All of the equipment necessary to use the range and the range itself are maintained and managed by BAE SYSTEMS, thus eliminating many of the overheads to the end user. CWS continue to be involved in support as a sub-contractor, in true partnership fashion. The system is cleared for all NATO forces, including one or two non-NATO (such as the Swiss). If a new customer comes along, MoD approval is needed before it can set foot at RAF Waddington, but BAE Systems has had little problem so far and in general has excellent relations with both the MoD and hosting RAF.

BAE Systems operate a 'Turnkey' contracting system, i.e. it provides support and administration, the customer simply brings his aircraft and flies his allotted slots. A good recent example was the trialling of Airborne Instrumentation Subsystem (AIS) pods on Spanish Air Force Mirage F1s at RAF Coningsby, several weeks of pre-trial work enabled a successful two-day flying programme with the result that the F1s will be participating in NOMAD as an aggressor unit towards the end of the exercise.

Success is guaranteed - if a slot can't be flown due to weather, the customer doesn't pay. Charging is by the thirty-minute range slot - as long as the user is satisfied, he pays. If he isn't satisfied that BAE Systems fulfilled all the criteria for a successful mission, again he isn't obliged to pay. It is rare that the Service Provider goes to this length in ensuring customer satisfaction, but its success can be measured by the very frequent return visits of the Belgians, French and Swiss Air Forces.

Only one customer at a time pays for the range slot - he may invite other forces to join in the fun, or simply undertake one-on-one or two-on-two sorties from within his own unit. Spread over the year, the training is shared out fairly evenly over the air forces seen at Waddington and the other Display and Debrief Sub-Systems (DDS) bases.

The Hardware

Much of the range equipment is located in the North Sea range complex located well off shore from the UK mainland in danger areas known as EG D316 and EG D317. The hub of the range is six oil rig-like tower structures anchored to the seabed known as ‘Tracking Instrumentation Sub-system Towers’, (TIS). These are arranged in a circle of thirty nautical miles diameter, with five TIS towers around the circumference and a single TIS master tower in the centre of the circle. Its remote location allows aircrew to practise unhindered by the normal environmental and airspace restrictions found elsewhere. This allows missions to be flown at almost all levels and speeds, including supersonic, plus of course active and passive countermeasures can be employed for more realistic training scenarios.

Each aircraft carries an AIS data pod, usually on the wing. The AIS pods contain sophisticated electronics and when airborne and within range of the TIS towers the pod is electronically 'interrogated' by equipment on each of the towers. Signals and telemetry data from the AIS pod is in turn 'echoed' back to the TIS towers and they then send this data to the central master tower. The master tower then sends the digital information via a cable buried underneath the sea bed to an on-shore master computer system, known as the Control and Computation Sub-system, (CCS), where the information is processed.

The AIS pod (P4A-M) is two-thirds the weight of an AIM-9 Sidewinder, although physically a bit bigger. A single pod is mounted on the aircraft wing tip launch rail or under wing pylon with power and data connections to the host aircraft via a standard NATO Sidewinder umbilical cord. The CofG and flutter characteristics are virtually identical to that of the real missile. As the French Air Force doesn't operate Sidewinder, an agreement with Matra was made whereby BAE Systems converted a NECA tube (basically a Magique missile) with the innards from a standard AIS pod. This enables all Mirage equipped units, and indeed air forces, to utilise the ACMI downlinking facility. Because of this, talks are currently being held with the Greek Air Force with the view to detachments trialling the NECA-based system, but ironically funding in Greece may be difficult in the next few years as its Government switches attention to the forthcoming Olympics in 2004.

Each pod has a unique digital code number allowing aircraft on the range to be individually identified. The pods have a 'spike' like pitot-static head at the front and internally a radar altimeter and air data sensor. These provide airspeed, altitude, yaw, pitch and roll information via a built in transponder to the TIS Towers every 20 milliseconds. The AIS pod is in turn 'interrogated' by electronics on the TIS towers every 100 milliseconds and through comparison of the data between the towers an accurate fix is achieved on the aircraft to within 4.5m (15ft).

Other data relayed via the AIS includes angle of attack, G, and radar antennae train angle (ATA), or seeker head look angle. It also provides Radar Warning Receiver (RWR) information and data on weapons selection and firing signals which are subsequently interpreted by the CCS computer to enable it to generate a simulated weapons release and performance at the time of firing. All this data can be replayed later via the DDS consoles to provide an accurate and detailed picture of each combatant aircraft's performance.

The AIS pods allow each aircraft to be tracked three-dimensionally as well as providing data on airspeed, altitude and many other factors. If an aircraft elects to simulate firing a weapon this data is also transmitted back from the pod with the CCS computer electronically 'firing' and simulating the weapons parameters and eventual outcome from data programmed in its memory. The CCS can handle up to fifty simultaneous missile trajectories. Data to and from each aircraft's wing-mounted AIS pod is received by the five outer TIS towers encircling the range and forwarded to the central TIS master tower via fibre optic cables. From the master tower there is a further dedicated fibre optic cable buried under the sea bed that relays this data via BT's commercial 'Megastream' network to the CCS located on shore at RAF Coningsby in Lincolnshire, UK.

As the fight is in progress the CCS can relay data in 'real time' to debriefing consoles being referred to as Display and Debrief Sub-Systems (DDS). The DDS consoles are the user interface and allow real time observation and later replay of the mission. The DDS units also allow active intervention of the fight for safety reasons or intentionally by GCI controllers by transmitting back through the system via a UHF link on the central TIS master tower. It also allows real time 'kills' to be called on 'splashed' targets thus making the whole fight more realistic and precise. Primary DDS facilities are located in the UK at RAF Waddington, RAF Coningsby, RAF Lakenheath and in the Netherlands at Leeuwarden AB. Leeuwarden's DDS also supplies data to two other Dutch Air Force bases at Volkel and Twenthe who have DDS(R)s - Display and Debrief Sub-system Remotes. These are only capable of providing debriefing information and do not allow for active intervention in missions by controllers. These DDS(R)s can however be transported to other locations unlike the fixed DDS systems.

Upon recovery to one of the DDS locations, aircrew can then replay the whole fight. Data recorded from the AIS pods on each aircraft allows a detailed analysis to be made of each intercept, manoeuvre and 'kill'. Aircraft can be shown on the consoles from various perspectives and with all flight parameters such as altitude, speed, G and so on. Via large flicker free screens, the fight can be watched in all the same detail as noted above and in addition it can be viewed in slow motion, freeze-framed or fast forwarded like any video recorder. Hard copy print cuts are also available for later study as well.

The crucial weapons release and the success or failure of hitting the target are also shown and all of this data combines to provide an ability to learn more effectively from each sortie. The DDS allows for monitoring or controlling of missions taking part in the range in 'real time' by a range officer who is in contact with each aircraft. With the pre-programmed aircraft parameters of each aircraft type the range officer is warned of any impending loss of flight control immediately so that he can intervene should the 'fight' become unsafe. A 3-D interactive display is the main system control element which personnel can use to view the fight.

Various scale magnifications can be used to zoom-out to the 'big-picture' or zoom-in to see aircraft at much closer detail. Console operators are also able to see the range from any angle - 360 degrees in azimuth or 0 degrees (from sea level) to 90 degrees ('God's eye' view). In addition they are also able to select a cockpit view as seen by any of the participating aircraft which shows every detail including HUD display, horizon, sun position and even cockpit framing! In the big picture individual aircraft types are recognisable by their shape and their path of flight is shown by lines which emanate from the wing tips in a trail fashion. Missile shot and 'kills' are also clearly shown.

The beauty of the system is that the DDS's are all linked via a secure encrypted data link which means a single mission can be debriefed at different locations. For example if a Swiss air force mission is briefed to work with the Netherlands Airforce, the Dutch pilots do not have to land at RAF Waddington to debrief. They can recover to a DDS location such as Leeuwarden, Volkel or Twenthe in Holland and discuss and see the same debriefing picture as the Swiss crews sat at the DDS at RAF Waddington.

Missile simulation within the CCS software is based upon a generic system, built up over time by BAE Systems using information within the public domain, particularly important in overcoming American security regulations. One of BAE Systems' simulations is called BLAST - 'BAE Systems Long-range Active Simulation for Training' - which is an AMRAAM look-alike. Using a generic missile provides a simpler form of debrief, but it is a good baseline as a 'kill' with a generic missile will probably have a lower confidence factor than one with a more sophisticated model, so if a hit is made the pilot can be fairly assured that his tactics are sound for a whole range of similar missile types. The intention of the range is to make the pilot situationally aware, not explore the outer envelope of a particular type of missile. Guns can also be simulated, but is not often utilised.

Not just air-to-air

ACMI also has other benefits besides pure training - it provides plenty of Air Traffic training opportunities at Waddington, which otherwise has relatively few movements with only ten active aircraft on the resident squadrons' strength. It also brings a fair amount of business to the local area, especially vehicle hire and accommodation.

Mike Elsam, General Manager for the North Sea Range explained some of the features of BAE Systems' ACMI facility: "Although the system can only handle thirty-six on the screen, we can load as many as have got pods. We've had up to forty-three on occasion, feeding new pilots in as others drop out. We can hear and record aircraft transmissions right down to sea level - that is a very important part of the package for the air defence mission."

Emphasising the value of the ACMI facility to the pilots was Group Captain Paul Colley, OC 43(F) Squadron. "Debriefing face-to-face - I can't overstate the value of that. The North Sea range provides unambiguous information to analyse tactics and de-brief the mission to a very high degree of fidelity. We cannot do that day-to-day to anything like the same magnitude."

"You can plan tactics, come up with ideas, but what we find out on the range is that you cannot replicate the unknowns, the 'fog of war'. The de-brief facility allows us to see how robust our tactics are in the face of all these imponderables that you cannot replicate or prepare for. Losing is not an option - we have to dominate an airspace, and this facility is a great enabler to do that." Crews take the opportunity for check rides in other air forces aircraft during the exercise, particularly in the two-seat F-16Bs and F/A-18Ds.

The new rangeless ACMI systems and the future of NSAR

The future of BAE Systems' North Sea Range has been questioned in the light of development of new 'Rangeless' ACMI systems such as RAIDS (Rangeless Airborne Instrumented Debriefing System) and URITS (USAFE Rangeless Interim Training System). Matra BAe Dynamics (MBD) has been selected as the UK MoD's preferred bidder for its RAIDS requirement. The MBD's Air Combat Training Inter-Operable Nato System (ACTIONS) has been chosen to supply RAF Fast Jet Squadrons with a new system that will allow pilots to train anywhere as long as co-operating aircraft are carrying similar equipment. ACTIONS is based on an airborne electronic subsystem contained in a missile shaped pod and on a ground station subsystem for the debriefing of aircrew. Furthermore, a real time tracking station can be added to monitor training missions in real time.

Matra BAe Dynamics has involved MLM (the Electronics Division of Israel Aircraft Industries) and Cubic Defence Systems of the US. Cubic will provide its advanced PC-based aircrew debriefing system for the UK's Rangeless Airborne Instrumented Debriefing System (RAIDS) under a contract awarded by Matra BAe Dynamics. The Cubic debriefing system, called the Individual Combat Aircrew Display System (ICADS®), will enable Royal Air Force (RAF) aircrews to view in-flight events and data on a PC or laptop. The data can be viewed in real time during the air combat training exercises or during post-mission debriefs to improve the effectiveness of RAF Fast-Jet training. The new system, which is due to be operational in November 2002, will allow Tornado, Harrier, Jaguar and Hawk aircrew to train together in the same combat environment.

However, these new systems may not be the panacea some believe, as Mike Elsam explained. "It's not a question of competition with the new rangeless systems. There are very big issues surrounding the new pods that are only just becoming realised. It is entirely suitable for the ground-attack community, but when you move into the Air Defence environment, you need to be in an area where you can go supersonic, use chaff and flares, EW if you've got it, and so you're going to have to do it well out to sea. Furthermore, aircraft-to-aircraft datalink is essential for 'kill-removal'."

New systems such as RAIDS, URITS and the Israeli EHUD cannot 'talk' to each other, rendering DACT type scenarios impossible. Mike continues: "The trouble with the new systems that are being brought in is that they are based upon an 'S' type datalink which is very short-range, maybe fifty to sixty miles max, nothing like enough for the current generation of modern fighters in the BVR scenario. The current North Sea Range infrastructure can be used to site transponders with directional aerial feeds so that any or all of the different types of systems can interlink and extend the physical range. Other advantages are that you can record the audio, do live monitoring, instruct pilots and navigators during the mission. So, the range isn't long enough, they're not interoperable, they don't do audio, you can't downlink without extra equipment - you can put a truck anywhere overland, but over the sea you need some fixed points."

NATO Industrial Air Group has been formed looking into the problems of interoperability, extending the range of these new systems. "As BAE Systems owns part of MBD, we can just put the two (the old range and the new systems) together", said Mike. "North Sea Range pods and tracking system will inevitably be phased out, but underpinning the new systems will be the infrastructure and a lot of our experience in networked datalinking, so it won't be a case of the baby out with the bathwater."

NOMAD is special, because of the air forces present and the types of aircraft present. As the customers want to put more of their pilots through the system, NOMAD may well happen more than once a year, albeit on a slimmed-down basis each time.

Aircraft present for Exercise Nomad

RAF/43 Sqn, Tornado F3 (Delta Dispersal).

RN/800 Sqn, Sea Harrier F/A2 (Engine Running Platform).

FAB/2 Wing & FAB/10 Wings, F-16AM (Charlie Dispersal).

EdlA/Ala 12, EF-18A (Bravo Dispersal).

Swiss AF, F/A-18C (Bravo Dispersal).

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