Modern air forces have become dependent on airborne radars typically carried by converted airliners and transport aircraft such as the E-3 Sentry and A-50 'Mainstay'. They also depend on similar aircraft for inflight refuelling (e.g. Vickers VC10), maritime patrol (e.g. CP-140 Aurora), reconnaissance and electronic warfare (e.g. Tu-16 'Badger' E & J) and C4ISTAR (e.g. VC-25 "Air Force One"). The loss of just one of these aircraft can have a significant effect on fighting capability, and they are usually heavily defended by fighter escorts. A long-range air-to-air missile offers the prospect of bringing down the target without having to fight a way through the fighter screen. Given the potential importance of "blinding" Western AWACS, Russia has devoted considerable resources to this area. The R-37 (missile) (AA-13 'Arrow') is an evolution of their R-33 (AA-9 'Amos') with a range of up to 400 km (220 nmi), and there have been persistent rumours – if little hard evidence – of an air-to-air missile with a range of 200 km (110 nmi) based on Zvezda's Kh-31 anti-radar/anti-shipping missile or its Chinese derivative, the YJ-91.

NPO Novator started work in 1991 on a very long-range air-to-air missile with the Russian project designation Izdeliye 172.^[5] Initially called the AAM-L (RVV-L), it made its first public appearance at the International Defence Exhibition in Abu Dhabi in early 1993,^[6] followed by the Moscow Air Show later that year.^[5] It was described as having a range of 400 km (220 nmi); the mockup on display had a strong resemblance to the 9K37M1 Buk-M (SA-11 'Gadfly'). Apparently some flight-testing was done on a Su-27, but it appears that the Russians withdrew funding for the project soon afterwards.

The missile resurfaced as the KS–172 in 1999,^[6] as part of a new export-led strategy^[7] whereby foreign investment in a 300 km (160 nmi)-range export model^[6] would ultimately fund a version for the Russian airforce.^[7] Again it appears that there were no takers.

In late 2003, the missile was offered again on the export market as the 172S-1.^[5] In March 2004, India was reported to have invested in the project and to be "negotiating a partnership" to develop the "R-172".^[8] In May 2005 the Indians were said to have finalised "an arrangement to fund final development and licence produce the weapon" in a joint venture similar to that which produced the successful BrahMos cruise missile.^[9] Since then the missile has had a higher profile, appearing at the 2005 Moscow Air Show^[5] on a Su-30 as the K-172,^[4] and a modified version being shown at the 2007 Moscow Air Show designated as the K-100-1. This name first appeared in a Sukhoi document in 2006,^[5] and sources such as Jane's now refer to the missile as the K-100.^[5] Nowadays the missile is not in commission whether in Russia nor in India. Supposedly the development was stopped and the project closed by 2010.

The mockup shown in 1993 had a strong resemblance to the Buk airframe, but since the Indians became involved there have been some changes. An Indian magazine gave the specifications of the KS–172 in April 2004 as a core 6.01 m long and 40 cm in diameter with a wingspan of 61 cm, with a booster of 1.4 m, and 748 kg total weight.^[1] It had a solid fuel tandem rocket booster capable of speeds up to 4,000 km/h (2,500 mph), 12g manoeuvring, and an adaptive HE fragmentation warhead.^[1] Development would concentrate on the seeker head, autopilot, resistance to jamming and a steering system with 3D thrust vector control (TVC).^[1]

In May 2005 it was reported that there were two versions, with and without a rocket booster, with ranges of 400 km and 300 km respectively.^[9] At the MAKS (air show) in August 2005, a range of 300 km was quoted for a streamlined missile with a small booster and fins on both booster and fuselage.^[4] However the model shown at the 2007 MAKS airshow under the name K-100 was closer to the original 1993 mockup in the photo above, with different-shaped fins that were further up the fuselage, and an even larger booster with TVC vents.^[10] At the same show it was shown under the wing of a Su-35BM, implying that at least two could be carried by Flanker-class aircraft rather than just one on the centreline.

Guidance is by inertial navigation until the missile is close enough to the target to use active radar for terminal homing.^[1] The K-100 has an enlarged (350 mm (14 in)) derivative of the Agat 9B-1103M seeker used in the R-27 (air-to-air missile) (AA-10 'Alamo').^[2] It has a lock-on range of 40 km (22 nmi), described by an Agat designer as "one fifth or less of the overall range".^[2]

• KS-172

Prototype in 1993.

• KS-172S-1

Prototype in 2003.

• R-37 (missile) (AA-X-13/AA-13 'Arrow') was developed from the R-33 (missile) (AA-9 'Amos') and is intended for the Sukhoi Su-35 Flanker-E, Sukhoi Su-37 Flanker-F, MiG 1.42 MFI and other future fighters.^[9] According to Defence Today the range depends on the flight profile, from 80 nautical miles (150 km) for a direct shot^[9] to 215 nautical miles (398 km) for a cruise glide profile.^[9] Jane's reports two variants, the R-37 and the R-37M; the latter has a jettisonable rocket booster that increases the range to "300-400km" (160–220nmi).^[3] Work on the missile appears to have restarted in late 2006,^[3] as part of the MiG-31BM programme^[3] to update the Foxhound with a new radar and ground attack capability.
• Kh-31 (AS-17 'Krypton') – the Chinese have licensed the anti-radar version (Kh-31P) of this Russian air-to-surface missile, and may be working on an "AWACS killer" variant of their YJ-91 derivative.^[9] The Russians claim the anti-shipping version, the Kh-31A, can be adapted for use as an AWACS killer.^[9]
• AIM-54 Phoenix – Now retired, a 100 nautical miles (190 km)-range missile that was carried by the US Navy's F-14 Tomcat.
• AIM-97 Seekbat - based on the Standard Missile SAM, the Seekbat was an extremely long-ranged missile designed to shoot down the MiG-25 Foxbat, which at the time had almost mythical performance estimates. When the real-world performance of the Foxbat was found to be dramatically less impressive, development was cancelled.

• AIM-152 AAAM
• FMRAAM
• Meteor (missile)
• R-37 (missile)
• PL-21

• sukhoi.ru – unofficial site with photos from MAKS air show; photos 10,12 and 13 show the K-100 on the ground of which maks2007d1013.jpg is perhaps the best.