2017/03/16

Air superiority in a European war in the next years (III)

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The previous (part II) assumption of perfect visibility in air combat eliminated any purpose of AEW (airborne early warning) aircraft (colloquially called AWACS). Such aircraft may have great utility in real air war conditions when fighters are not fully aware of the positions and movement of all other planes, of course.

The importance of AEW stems in large part from the limitations of air search radars on the surface, especially the line of sight limitation which gives the bird's view AEW radar a much superior range against very low-flying targets. 

AEWs also provided area air search & target tracking far into hostile territory on some Third World-bashing expeditions, but that's unlikely to happen in Europe for reasons mentioned later.

AEW's real importance in a European air war would be different; most fighters have but one radar, which can search in the frontal up to 180°, but with AESA radars often only frontal ~ 110°. A radar searching like this is not searching perfectly, and may still fail to detect targets in range and in this cone, but more importantly the combat aircraft will fly at ~300 m/s while being largely blind on the left, right and towards the rear. One approach against this problem is to install multiple radars as was initially done in some late Suchoi fighters with a rear-facing radar, and much more ambitiously in the PAK-FA/Suchoi T-50.


expected PAK-FA radar fields of view
The better-established approach is to use AEW aircraft for this purpose; they stay behind friendly fighters, but their powerful long-range radars may see what's left and right and behind those friendly fighters, and inform the fighter pilot by datalink and/or voice comm.

The AEW approach is usually widened to the AEW&C ("& control") approach, with radar interpreters sitting in the very same aircraft and giving guidance (as well as airspace deconfliction permissions) to pilots as was otherwise done with land-based interceptor command & control centres as famously so in the Battle of Britain already. Only very large AEW&C aircraft provide many such workstations, while smaller ones based on Saab 340, E-2 or business jets provide only very few workstations. In theory it's not necessary to have any such workstations, for they could be replaced with a datalink and workstations in a container on the ground.

The AEW's importance for the situational awareness of friendly fighters is great. It enables them to not fly in a line, but trust that the AEW will keep a look at the regions not covered by fighter sensors. It even enables them to shut down their own radar and stop treacherous emissions for a while, improving their odds of survival and their odds of surprising a hostile pilot.

A loss of effective AEW support would be a severe blow to an air force, particularly to one which trusted AEW survivability and availability so very much that it didn't train much how to fight without AEW support, and didn't equip itself for such conditions.

A loss of AEW support would be expected when a strike package penetrates 'hostile' airspace deeply. AEW aircraft are typically not the most survivable ones, being derived from civilian platforms or using a dedicated very slow platform (E-2 and its Chinese copy). Nominal AEW ranges are typically claimed to be 300...450 km against fighters (it may be as low as 100 km against so-called generation 4.5 fighters which had some signature reductions in their design, but Russia has none of those), so it's quite safe to assume that a penetration of 'hostile' airspace at more than 300 km depth means a loss of AEW support, and thus becomes very unlikely to be a common occurrence in a European conflict.



This may go a long way to explain the interest in strike fighter-launched cruise missiles (Taurus, Storm Shadow, Apache, JASSM) since the 1990's; they extend the effective penetration by hundreds of kilometres without a strike package needing to penetrate 'hostile' airspace deeply (or at all).

IAI CAEW EL/W-2085, likely the best AEW system to date
with multi-band continuous 360° AESA radar coverage and high subsonic speed.
AWACS is antiquated by comparison. photo (c) "Owen65"
I wrote 'hostile', and that's actually a difficult to define term. I suppose AEW aircraft would avoid getting as close to hostile area air defences as their maximum range. They might survive flying a few dozen kilometres more close to the launcher, but AEW aircraft are expensive and thus few, so avoidable risks to them should be avoided.
This means AEW aircraft may be forced to stay up to about 400 km distant to potential hostile missile launchers, and those missile launchers could actually be with the most forward hostile land forces brigades. AEW might be able to detect normal combat aircraft as the ones currently in Russian service at such ranges, but detection at such a range would likely be unreliable. AEW support may thus be unsatisfactory even over the most forward friendly brigades which may very well be behind the most forward hostile land forces brigades.

Another threat that pushes AEW aircraft back is the threat of sprinting fighters. Many fighters can easily go Mach 1.3...1.8 with enough fuel and missiles to sprint into range with the AEW aircraft, and PAK-FA may even fly at Mach 1.6 "supercruise" speed as its normal speed on air combat missions. Such fighters only need to be within maybe 70 km to the AEW system to  kill it, so AEWs need to commence to run away from such threats ASAP whenever there's a risk of such a sprint, even if the threat fighter is still at a much longer distance.* This may de facto push them back even further during much of the time because of many feints.

Long range air-to-air missiles make this fighter sprint easier (by greatly increasing the range at which a fighter can kill an AEW aircraft), if not even unnecessary. The Soviets have begun the development of such missiles and the Russians have continued it. The MiG-31 interceptor regularly uses particularly long-ranged missiles (R-33) and receives even longer-ranged ones, as will likely PAK-FA (R-37).  The Russians are so very much interested in this concept that they developed multiple such missile types (see KS-172). The published nominal ranges of such missiles go up to about 400 km, exceeding the range of some AEW radars against fighters. The firing solution may even be derived from passive triangulation of the AEW radar by ground-based electronic intelligence units.

Overall it can be said that some threats to AEW platforms are about equal if not superior to the AEW's radar in effective range. A MiG-31 detected by AWACS may already have AWACS within the no escape zone, and it would almost certainly be so with a PAK-FA detected first by the AEW's radar.

There's another very substantial problem with AEW; it hasn't encountered its main dedicated countermeasure/nemesis in a hot conflict yet. That's a ground-based radar jammer**, which is even offered on the export market by the Russians (which almost guarantees that they have a newer generation developed already). My old Jane's Radar and electronic warfare systems 2004/05 book offers multiple examples; Gradient Research Institute's low power jamming system and the Pelena-1 radar jammer, which was also in the 2003 Rosboron export catalogue already. Such jammers can mask aircraft in a large area against tracking by AWACS (larger region the smaller the radar cross section of the aircraft is) and in an even larger region against detection by AWACS. The claimed radii against AWACS are 80 and 250 km for Pelena-1. Again, the Russians likely have successor systems developed already.
Additionally, communications jammers may keep the AEW data from reaching intruding strike packages (the unlikely worst case would be a feeding of wrong info so the strike packages waste their missiles or even engage each other). Drones and civilian aircraft not essential to the war effort may also be used to create false contacts.

This means effectively that AEW would not be as useful for Europe's defence in the 2020's (as a consequence of various countermeasures) as it was for bombing Third World countries since the 1990's. It might end up not being a central pillar of NATO air warfare in Europe at all. We would likely be well-advised to either orient equipment and tactics for an air war scenario without effective AEW support or invest in much higher AEW survivability and thus persistence.***

S O
defence_and_freedom@gmx.de


P.S.: I think much more highly of AEW in a naval context, where more rarely hostile fighters are to be expected and fewer allied fighters might be in the air as well. I even think it's a more sensible approach to anti-air warfare in a naval context than to build dedicated AAW destroyers with huge air search & tracking radars (such dedicated AAW ships usually end up neglecting ASW in design and training). AEW support does allow warships to stop emitting radar signals themselves, and this weighs more heavily than with land-based air defences.Land-based air defence radars give away their own position and endanger themselves by emitting, while such radars on warships give away the entire ship's position and endanger the entire ship. A helicopter AEW is only acceptable out of range of hostile fighters (such as protecting a New York-Le Havre or San Diego-Pearl Harbour convoy against long-range bombers, for example) and a turboprop plane as AEW platform is never advisable. The USN should have developed a Mach 0.9 common support aircraft or at least a Viking AEW version IMO.

*: This is a huge problem with the Erieye's non-360° radar field of view and with the use of slow aircraft as AEW platforms in general. 
**: Emitting radar jammers can be engaged with anti-radar missiles just like emitting radars, but this would only be practical against a 'rear area' jammer in the context of a strike package, and would make said strike package even more challenging.
***: An increase in AEW effective range would not be very promising, since the radar cross section reduction by PAK-FA would largely counter it anyway. A nominal 350 km range and Mach 2 AEW platform might be much more promising than a nominal 500 km range and Mach 0.8 AEW. A Mach 2 running AEW could switch its radar off (leaving the active emissions to another AEW on station elsewhere), run and let the pursuing long-range missile miss because no sufficient midcourse guidance updates reach the missile by datalink. Both datalink jamming (by jammers on the ground) and generally running out of range of hostile sensors would enable this.
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