New-generation aircraft such as the Gripen, Rafale, Typhoon and F-22 are in service now or under test. Most attention is naturally focused on airframe-related advances - stealth, supersonic maneuverability and so on - but it is smaller, often overlooked details that may bring about a revolution in air combat and bring about some of the most important changes since the advent of the missile-armed supersonic fighter in the 1960s.
Within 10 years, many in-service fighters will be armed with new and much more lethal air-to-air missiles (AAMs). They will be carrying more advanced radars and other technologies which make it much less difficult to declare a target as hostile well beyond visual range. They will also be operating with tactical datalinks which allow several aircraft to share tactical information in a manner which is simply impossible for most aircraft today. Individual and formation tactics will change - but the implications of new technology are such that nobody knows exactly how that will happen.
AAM technology defines the depth of the air battle. "Whoever has the longest reach controls the engagement," comments fighter analyst Ben Lambeth of the Rand Corporation. Lambeth recalls flying on a mock engagement in 1996, a four-versus-four out of Eglin Air Force Base (AFB), Florida. F-15s armed with the AIM-120 Advanced Medium Range AAM (AMRAAM) took on four F-15s simulating MiG-29s armed with R-27 Alamo MRAAMs and R-73 Archer SRAAMs. "I never had a tally on any of the bad guys. I rarely saw our wingman. We never put more than 3g on the airplane and we never got inverted. There were missiles and people dying everywhere."
This result reflects today's level of technology, in which the within visual range (WVR) and beyond visual range (BVR) envelopes are separate. A BAE Systems paper from 1996 - reflecting the UK thinking that led to the adoption of the BAE Systems Meteor AAM for the Typhoon - points out that a target beyond 40km range "can feel free to maneuver without fear of engagement". This is echoed by Robert Shaw, former US Navy fighter pilot and author of Fighter Combat Tactics. "There is virtually no missile that you can't outmaneuver at maximum range."
With today's weapons, the BAE paper notes, most MRAAM engagements will take place between 15km and 40km-range. Older short-range AAMs "lack not only total energy but also missile speed" and are most lethal at ranges under 8km, according to BAE. Between 8km and 15km, therefore, there is a 'commit' zone where the target can still avoid a merge into close combat if the odds are unfavorable.
The key to the next generation of MRAAMs, such as Meteor, is greater range and (more importantly) greater energy at range. The result is a much larger "no-escape zone". This zone surrounds a target and defines the maximum range at which the target cannot out-maneuver a missile shot. The missile's kill probability may be almost constant from its minimum range out to 80km. (One issue here, observes Shaw, is that it may be difficult to confirm that the missile has found its target, particularly in poor visibility: this may be one reason why Meteor has a two-way datalink.)
Boeing has joined the Meteor program with the intention of marketing the missile in the US. The situation is complicated by the fact that the F-22 needs it less than other fighters. Earlier this year, F-22 chief test pilot Paul Metz confirmed that the F-22's speed and altitude capability acts as a booster stage for the common-or-garden AMRAAM. At M1.5 and at greater altitude than the target (the F-22 has a very fast climb rate and a service ceiling well above 50,000ft), AMRAAM's range is 50% greater than is the case in a subsonic, same-altitude launch.
New SRAAMs are faster than the AIM-9 (due to larger motors or smaller wings) and have new infrared (IR) dome materials which do not blind the seeker when they are heated by air friction. With imaging infrared (IIR) seekers, they are just as effective against a non-afterburning target as against a full-reheat target. Under some circumstances, a modern SRAAM is a BVR missile, capable of being cued on to the target by aircraft sensors and locking on to it at an extreme range of 12-20km. "You can expect to be engaged from about 80km inbound and enter a [MRAAM] no-escape zone shortly thereafter," notes the BAE paper. The commit decision must be made sooner and, if the target pilot commits, the target will enter an SRAAM no-escape zone.
Once the fighters 'merge' - that is, their momentum takes them within SRAAM range of each other, so that the first fighter to attempt to escape will offer his opponent an open tail-on shot - improved SRAAMs and helmet-mounted display (HMD) technology multiply the opportunities for WVR shots. It is no longer necessary to point the aircraft towards the adversary; any target within the field of regard of the missile seeker can be engaged instantly.
According to one source, US Marine Corps F/A-18 Hornets from the Balkans theater recently engaged in mock combat with Israeli Air Force fighters. The Hornets were armed with AIM-9s, and the Israeli fighters carried Python 3 and Python 4 missiles and Elbit DASH helmet sights. IDR's source describes the results as "more than ugly", the Israelis prevailing in 220 out of 240 engagements.
There are lessons to be learned from this engagement and other tests which have shown similar results. One is that modern HMDs and SRAAMs are essential. A second lesson is that WVR combat is extremely dangerous and will become more so. "We'll see less dogfighting once we get the ability to engage targets 90 off the nose," says Shaw. "Somebody's going to get a shot, and if the missile is lethal you're going to get hit." Even the recent history of engagements suggests that the 'furball' of fighter combat, with multiple engagements spread across miles of sky, is on its way out. "We don't see a history of high-g maneuvering in recent engagements," says one industry analyst. "It's fun to practice but unwise to pursue."
A third lesson is that WVR is an equalizer. "An F-5 or a MiG-21 with a high-off-boresight missile and HMD is as capable in a 1-v-1 as an F-22," comments a former navy fighter pilot, now a civilian program manager. "In visual combat, everybody dies at the same rate," says RAND's Lambeth. Indeed, he says that a larger fighter like the F-22 may be at a disadvantage. In the early 1980s force-on-force exercises at the navy's Top Gun fighter school, F-14s were routinely seen and shot down by smaller F-5s flown by the navy's Aggressor units. An F-22 which slows down to enter a WVR combat also gives up the advantage of supersonic maneuverability.
Close range confrontation
Nevertheless, the experts consulted by IDR agreed that the fighter still needs to have the ability to fight at close range - including having a gun. The current state of the debate on this highly controversial piece of equipment is that the F-22 has a gun - indeed, its M61A2 installation, complete with a neat power-actuated door over the muzzle, is one of the most complex ever seen - as does the US Air Force (USAF) version of the Joint Strike Fighter (JSF). The US Navy (USN) had apparentlyy decided at one point to forgo the gun on the JSF - which is primarily intended as a deep-strike aircraft - but Boeing program managers now say that there is an "ongoing debate" on the subject. The marines, concerned about vertical landing weight, have settled on a 'missionized' gun, installed in a package that replaces an internal bomb station. Both JSF competitors have selected a Boeing-developed version of the Mauser BK 27mm cannon, fitted with a linkless feed system by Western Design. The UK Royal Air Force has considered eliminating the gun from its second tranche of Typhoons, not so much to save weight as to eliminate training and support costs.
Combat identification technology
A limitation of Boeing's JSF simulations is that they do not reproduce the typical instantaneous opportunities for a gun shot, Boeing managers concede. Comments Shaw: "We're reluctant to [eliminate the gun] until we have something to replace it. Any missile has a minimum range." One argument for the gun is that, without it, the adversary has the option of evading a missile shot by a dramatic charge into the minimum-range envelope of the missile. But the hard fact, according to Lambeth, is that "you can count the gun kills since the Bekaa Valley on one hand". Israeli F-16s have five gun kills, and Pakistani aircraft have two.
If the WVR fight is dangerous, though, the key is to avoid it by destroying as many hostiles as possible in BVR, preferably at extreme range. One basic and vital requirement, being addressed by new technology, is improved combat identification. "If you impose visual identification [VID] on an F-22, it deprives you of 90% of what the aircraft can do," says Lambeth.
Rules of engagement (ROEs) set the conditions under which an unseen target can be attacked. They vary from situation to situation, under political constraints, but a basic principle is that the target should be 'declared' by multiple independent channels. This, in part, explains why F-15s claimed the overwhelming majority of air- to-air kills in Desert Storm. The F-15 was equipped with modern identification friend-or-foe (IFF) equipment and had a non- cooperative target recognition (NCTR) mode in its radar. The latter used jet engine modulation (JEM) processing to detect a characteristic beat in the radar return, associated with the target's spinning compressor blades, and is effective over a limited range of aspect angles. F/A-18s had similar NCTR but no equivalent IFF and F-14s had IFF but no NCTR, so they could not shoot without clearance from Airborne Warning and Control System (AWACS). (Similarly, recent export-model F-16s have a Northrop Grumman IFF which is superior to that fitted to most USAF aircraft.)
Target recognition
Newer radar NCTR techniques are classified but are believed to involve very precise range measurements. If the target's orientation is known, the distribution of the signature over very small range bins can yield a range profile which is characteristic of a certain aircraft type. BAE Systems says that the Typhoon's Captor radar has an NCTR mode based on "target adaptive waveforms". The Typhoon's EuroFIRST PIRATE (Passive InfraRed Airborne Tracking Equipment) operates as both an IR search and track system and as a long-range imager, permitting an equivalent VID beyond unaided visual range.
Increasingly, too, modern fighters such as the F-22 feature passive electronic receiver systems which are much more accurate in bearing than the simpler radar warning receiver (RWR) systems on today's fighters. If a hostile fighter uses its radar, these new systems can correlate the signal with a passive radar return, confirming that it is hostile.
Better radar performance also helps dominate the BVR battle. Dassault has noted that the Thales RBE2 electronically scanned radar on Rafale has a "track here while scan there" capability; for example, it can continue to track targets while searching another part of the sky. The Typhoon's mechanically scanned Captor radar always works in track-while-scan mode, because its performance is such that its search capability is ample when it is tracking known targets. 'Data adaptive scanning' technology allows the radar to refine its tracking of priority targets without wasted movements.
With better data from the radar, and a good chance to identify the threat BVR, the friendly fighters have both more time and more information to make decisions, sorting targets and committing forces - that is, assigning friendly aircraft and missiles to each target. This is what the US calls "information dominance"; the hostiles are still trying to sort out their targets, but there are already missiles in the air towards them.
Of the new generation of fighters, the F-22 and Typhoon will probably be in the best situation to avoid any return shots from the enemy. F-22 pilot Metz calls this 'cranking' - pulling a supersonic turn after firing a missile, forcing a hostile missile to maneuver with rapidly increasing line-of-sight rates. "Cranking after the shot always reduces the enemy's effective missile range, but a supercruise crank places the F-22 way outside an adversary's maximum range, even if it could detect the F-22," says Metz. Most fighters are relatively limited in their ability to maneuver at supersonic speed, but the F-22 (with a large wing area and immense thrust) and the highly unstable Typhoon are specifically designed to do so.
The datalink advantage
But the single biggest tactical advantage, particularly in the BVR fight, is a simple information-technology device: a datalink. At one level, a datalink is a harder-to-jam substitute for voice radio; but at another, it makes a group of aircraft appear almost telepathic.
Beyond any serious doubt, the Swedish Air Force (AF) has more experience with the operational use of datalinks than any other service in the world. Because of its proximity to the Soviet Union, the Swedish AF recognized that it was vulnerable to communications jamming, and initially adopted ground-to-air links for the J35 Draken in 1963-65. The system was so secret that it was cunningly disguised in the cockpit and could never be mentioned on voice transmissions. The first 'fighter link', including aircraft-to- aircraft two-way transmission, was also deployed secretly, aboard the JA 37 Viggen in the early 1980s. The system deployed aboard the Gripen builds on this experience.
The Tactical Information Datalink System (TIDLS) can connect up to four aircraft in a full two-way link. It has a range of 500km and is highly resistant to jamming. Its basic modes include the ability to display the position, bearing and speed of all four aircraft in a formation on a tactical information system, including basic status information such as fuel and weapons state. The Swedish AF has already proven some of the advantages of the link, including the ability to spread the formation over a much wider area.
A basic use of the datalink is 'silent attack'. An adversary may be aware that he is being tracked by a fighter radar that is outside missile range. He may not be aware that another, closer fighter is receiving that tracking data and is preparing for a missile launch without using its own radar.
But the use of the link goes beyond this, towards what the Swedish AF calls 'samverkan', or close-cooperation. One example is the use of the Ericsson PS-05/A radar with TIDLS. An Ericsson paper compares its application, with identical sensors and precise knowledge of the location of both platforms, to human twins: "Communication is possible without explaining everything."
"Radar-samverkan," the Ericsson paper suggests, equips the formation with a super-radar of extraordinary capabilities. The PS-05/A can operate in passive mode, as a sensitive receiver with high directional accuracy (due to its large antenna). Two PS-05/As can exchange information by datalink and locate the target by triangulation. The target's signals will often identify it as well.
The datalink results in better tracking. Usually, three plots (echoes) are needed to track a target in track-while-scan. The datalink allows the radars to share plots, not just tracks; even if none of the aircraft in a formation gets enough plots on its own to track the target, they may do so collectively.
Each radar plot includes Doppler velocity, which provides the individual aircraft with range-rate data. However, this data on its own does not yield the velocity of the target. Using TIDLS, two fighters can take simultaneous range-rate readings and thereby determine the target's track instantly, reducing the need for radar transmission.
Anti-jamming techniques
In ECM applications, one fighter can search while the wingman simultaneously focuses jamming on the same target, using the radar. This makes it very difficult for the target to intercept or jam the radar that is tracking him. Another anti-jamming technique is for all four radars to illuminate the same target simultaneously at different frequencies.
The 14 two-seaters in the third and final Gripen batch are different from the JAS 39B trainer. The JAS 39D will be a dedicated information warfare platform with a redesigned rear cockpit. The flight controls are removed and replaced by large-format displays. The JAS 39D will host different levels of backseaters, including a dedicated radar operator who can control all the radar sensors within a group. The overarching mission is to achieve information dominance; that is, to ensure that friendly assets have the best information possible while destroying or jamming the enemy's information resources.
Sweden's plans for Unmanned Aerial Vehicles (UAVs) and Uninhabited Combat Air Vehicles (UCAVs) are based on the use of the datalink. With the link, a semi-autonomous UCAV can co-operate with a formation of manned fighters. Avoiding conflicts between the UCAV and other aircraft becomes a natural extension of normal datalink use; the UCAV can be used for tasks such as the suppression of enemy air defenses, and to identify targets at close range.
However, none of the experts consulted by IDR see a possibility that the UCAV will replace the fighter in the near future. There is no substitute for the situational awareness of the pilot, particularly in the complex three-dimensional air battle. On the other hand, it is also clear that the use of datalinks and long- range weapons will allow manned fighters to control much larger areas.
The process of tactical change - which is traditionally slow except in combat - should be accelerated by the use of full-mission, multiple-player simulators. "Traditionally, you fly the new aircraft like the old one until you figure it out," remarks a former F-15 pilot who now works on the Boeing JSF team. "It took us 10 years to employ the F-15 like an F-15, and not like an F-4." With simulation "we'll do the same in four to five years".