Sir, the KS-172 is a heavy long-range AAM is meant for slow lumbering force multipliers like AWACS, Air to Air refuellers and ELINT aircraft. They are not as manoeuvrable as the fighters they support and hence a relatively lesser manoeuvrable missile like the KS-172 which is derived from the Buk SAM is used to knock them out. It is the heaviest air to air missile ever designed. They have a longer burning rocket motor which grants them long-range, and they have a bigger warhead to knock out bigger aircraft in one shot. Due to their primary targets being lesser manoeuvrable, less emphasis is placed on their manoeuvrability, when they were being designed. As a matter of fact, if this missile is fired at a highly manoeuvrable target like a fighter at long range, there are chances that the missile may be evaded by the fighter by simply using evasive manoeuvres and quick acceleration. The development of these missiles was bankrolled by India to arm our Sukhois, however, the current status of the missile and whether we have it in our arsenal is unknown. The Russians have however developed the R-37M for their Mig-31BM interceptor for a role similar to the KS-172. A funny fact is, the longest range missile currently in use is the American AIM-54 Phoenix missile, used by the Iranian’s on their F-14’s. Its also suspected that a bramhos missile variant is being developed as a long-range air to air missile.
The world of BVR combat is highly complex and the BVR tactics in use by air forces globally are closely guarded secrets. The so-called advertised range of many missiles is a marketing tool. The max range as depicted is under standard testing conditions, much like how cars give maximum fuel efficiency under standard ARAI testing conditions. Many factors like height of the firing aircraft, its speed, its angle, height of the target, its speed, its manoeuvrability, its EW system, air temperature, wind speed and even humidity affect actual BVR range. For example, an R-77 fired by a Sukhoi-30 at 55000 ft, when flying at Mach 1.5 will have a range almost 30% higher, than a similar R-77 fired by the same plane, if it were flying at Mach 1 between 30-40000 feet. The lower and slower you fly, the lower is your range of firing. From OSINT resources, it is claimed that our Su-30’s were flying at around 15-20000 feet when they were intercepting the Pakistani F-16’s flying at higher altitudes. Due to their higher height, the PAF could fire their AMRAAMs, whilst the firing computers could not calculate firing solutions for R-77’s and R-27’s from the Su-30’s due to their height disadvantage. The PAF and IAF missiles didn’t have a big difference in firing range, however, here altitude at which they were fired played the clinching role in deciding who fired and who didn’t. Due to these conditions, please don’t think that the Meteor is a silver bullet which can shoot every aircraft it’s fired against. Yes, it has the best no escape zone amongst all missiles currently and it’s going to be the best AAM in Asia, yet it too has its firing limitations.
Due to these limitations which all missiles have, pilots are trained to fire their BVR’s under optimal conditions as far as possible to attain a kill. But, mind well of the fact that BVR fighting is a very very fluid, kinetic and tricky. At a range of above 100 km with multiple planes in the air, no amount of IFF can 100% determine whether the target is an enemy fighter or a civil/friendly aircraft. You, cannot fire till you are 100% sure it’s an enemy plane. Yes, in today’s day and age, ground-based radar and AWACS can give a clearer picture, but nothing is better than the Mk 1 eyeball. The Americans in Vietnam had advanced Semi-Active Radar Guided BVR’s for their time, but they avoided shooting down opposing planes for the fear of a blue on blue kill. Hence a majority of the American kills in Vietnam were WVR kills with many of them being good old gun kills. Now, in today’s scenario in a contested environment with massive EW deployment, the chances for a friendly kill increase.
Also, pilots are trained to avoid the use of their own radar as much as possible to detect enemy fighters from a long-range, as it will require them to use their radar at max power, which will expose their position to enemy passive radar sensors, and it will give the enemy vital ELINT of our radar signatures. Theoretically, a Sukhoi can detect enemy planes at around 300 km with its Bars PESA Radar, however, it will entail it giving up its position and making it vulnerable to jamming as all its transmitting frequencies will be known to enemy sensors. Hence long-range scanning is mostly always done by bigger and more powerful AWACS or ground-based radars. They pass on tracking info to friendly fighters, who then use it to fire their active/semi-active missiles. Fighter radars are used only intermittently for short bursts to calculate the final firing computation before missiles are fired. Due to all these factors, nowadays frontline fighters are using better and better passive infrared and UV sensors to detect enemy fighters, without themselves being detected.
Coming to missiles. The Meteor is considered the best in its class mainly due to its Ramjet propulsion, which enables it to be powered for a longer duration of its flight as compared to rocket motor powered missiles. The longer duration of propulsion enables it to actively manoeuvre without bleeding energy when engaging manoeuvring targets, thereby increasing its lethality and no escape zone. A rocket-powered missile like the Astra/Amraam/R-27/R-77/Derby is powered by its rocket motor which burns out in 20-25 seconds post-launch (hence due to this short life, absolute speed of the launching aircraft becomes important in determining range). Post the burnout, the missile glides towards its target, and if the target manoeuvres, it bleeds kinetic energy to keep up with the target, hence reducing its velocity and range. Hence nowadays ramjet-powered missiles are in vogue so that the range becomes longer due to longer powered flight time. Ramjet powered missiles are expensive, hence dual pulse solid-fuel rocket motors are being used to lengthen the range. In case of dual pulse motors, the initial phase is powered, followed by an unpowered glide, followed by a second powered phase during the endgame phase, so that it can keep up with a manoeuvring target. As an example, our own Astra Mk1 is a single-phase rocket motor-powered, with an advertised range of 110 km in the head-on chase and 20-30 km for tail chase mode. The solid fuel ducted ramjet and dual pulse motor-powered variants of the Astra are now under development.
As per OSINT sources widely available online, IAF follows a dual missile launch philosophy, with one radar-guided missile and one IR guided missile like the R-73 being fired at all targets to maximize kill probability. The radar-guided missile of IAF’s choice is the R-27 as it has a slightly longer burn time vis a vis the R-77. The newer variants of the R-27 are equal in EW capability to the R-77, and in the emergency purchases done post balakot, we purchased the newest most capable variants of the R-27 to arm the Su-30 and Mig-29. For the M2K we have both IR and Radar guided versions of the MICA missile. Now with better datalinks, IAF will develop the co-operative engagement capability similar to the Indian Navy, wherein a missile launched by one aircraft can be guided to its target using targeting data acquired by other platforms. Navy has already demonstrated it by using a Barak-8 launched by INS Kochi was guided to its target by using data from INS Chennai.
At the end I would like to state that our future AAM inventory will be one of the world’s best with the Astra’s forming the bulk of the radar guided BVR missiles ably accompanied by the R-27’s and Meteors, and ASRAAM’s, R-73’s, MICA’s and Python’s forming the bulk of the close engagement missiles.
For anyone interested in reading more, this is a lovely article.
https://www.ausairpower.net/APA-Rus-BVR-AAM.html