BAeD ALARM: Long ARM of the RAF

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Introduction: The ALARM (Air-Launched Anti-Radiation Missile), was Britain’s primary anti-radiation missile for three decades, designed in response to the advancement of Soviet radar defences, possessing a unique capability that was a novel feature for the time.


Background: The RAF had long developed tactics to counter radar systems, with such missions dating back to the Second World War. As technology improved, so did the countermeasures and tactics. The Air Staff took a keen interest in the events and actions undertaken by the Americans in the Vietnam War and the Israelis in both the Six Day War and the Yom Kippur War, and greatly appreciated the developments and tactics that were done during these conflicts. At this point, the RAF acquire the AS.37 ARM, but they were less than impressed with its performance, and it suffered numerous issues during its career. Such was the RAF’s dissatisfaction with the missile that they ordered the AGM-45 Shrike for use in the Falklands War. As the Seventies rolled in, the Air Staff was quick to understand that existing equipment would not be able to counter the evolving threat of Soviet Air Defence systems.


Development: In November 1975, AST.1228 was drawn up for an anti-radar system that would be fit for the 1980’s. The Air Staff had conducted a number of studies and found that “unless positive steps are taken to reduce the effectiveness of the defences”, RAF strike aircraft would suffer from very high attrition rates. The main threats were the SA-8 Gecko, the ZSU-23-4 Shilka, the SA-6 Gainful and the S-60 AA guns, located mostly in and around the frontlines, up to about 20km. The system was also meant to counter dug in positions such as the SA-2 Guideline, SA-3 Goa and SA-4 Ganef SAMs, being able to counter their guard radars. These systems were smaller systems that were designed to detect oncoming attacks and either shut down the main system, or warn the operator. This ability to attack a radar system even if it was shutoff would be a defining feature of the eventual system. Finally, the system was also intended to be employed in an offensive counter-air role, up to 250km behind the frontlines.Numerous different system types were put forward, these being: delivery vehicles, decoys, glide bombs, air-launched missiles, ground-launched missiles and harassment drones. The main weapon of interest if the ALSP (Air-Launched Sub-Projectile).


The ALSP looked outwardly like an enlarged Rapier. Its forward bodyshell formed a sabot around a warhead. The missile would employ a ballistic trajectory, thus allowing it to attack missiles in dugouts. This was aided by the use of a set parachutes, the first set would be used to slow the missile down, while the second would slow it down further and orient it vertically. The missile had a range of 26.5km, which saw it climb to 17,000m, before deploying its parachute system at 12000m, and releasing its sub-projectile.Of all the options put forward, the ALSP was chosen in 1979 for continuation, with some modifications. The sabot system was discarded, allowing for a larger warhead and seeker, the latter of which allowed for better detection radius, and in a “wide band in a dense radar environment”. The nose was also rounded off and a few small fins were added. These modifications led to the ALARM. Despite design work being completely finished, the project was put on the back-burner in 1979, due to cost. BAeD and MSDS continued work privately, and work was re-established three years later.


In HARM’s way: However, it was not plain sailing from here, as HARM entered the fray. Texas Industries (TI) offered to produce it in the UK, and at a cheaper cost than ALARM. However, TI refused to release performance details of the missile, which gave the Air Staff the impression that it did not meet the requirement. On top of this, the HARM was already in service, and would have required an MLU quicker than ALARM, thus negating the cost savings benefit. This was in addition to the fact that it did not allow for much growth potential. Finally, the industrial aspect was at play; ALARM allowed the missile seeker design team at MSDS to be retained, as well as keeping work within the UK. If this were not to occur, it would have likely jeopardised any future missile development in the United Kingdom. Lots of political to-and-fro went on, but in the end, ALARM was chosen on the basis that it offered greater flexibility and could be fitted to any aircraft.


Service: Trials began in 1985 at Warton. All went well, besides problems with the Nuthatch rocket motor, which suffered from many issues during development, and was eventually swapped for a simpler Bayer Chemie Bayard motor. Further trials occurred at the China Lake test range in the United States, before rapidly entering service in 1990, just in time for Operation Granby the following year, in which 121 missiles were fired, with great success. The missile was updated in the following years, incorporating lessons from the conflict. The missile was used in Operation Allied Force, where a radar site which had taken around 100 unsuccessful attempts at being shut down with HARM from F-16Cs, EA-6Bs and Tornado ECRs, was destroyed by a single ALARM from an RAF Tornado. ALARM was also utilised to a great degree in Operation Telic in 2003, and in Operation Ellamy in 2011, against Iraq and Libya respectively. The missile has also been reportedly used by the Saudis in Yemen.

Retirement: The ALARM missile system was retired from RAF service in 2013, with no direct replacement. Currently, the anti-radar role is done via Brimstone or Storm Shadow, or under cover from other NATO allies. Despite this, proposals for ARMs based off of the Meteor BVRAAM and SPEAR 3 have been put forward, and it is possible that either of these may enter service. It reportedly remains in use with the Saudis.

Aircraft that carried/were intended to carry this system:

  • Panavia Tornado GR.1
  • Panavia Tornado F.3 (aircraft modified referred to informally as EF.3)
  • Panavia Tornado GR.4
  • BAE Harrier GR.7
  • BAE Sea Harrier FA.2
  • SEPECAT Jaguar GR.1A
  • BAE Hawk 100
  • BAE Nimrod MRA.4
  • Eurofighter Typhoon




ALARM Specifications
Type Air Launched Anti-Radiation Missile
Manufacturer BAe Systems
Weight 265kg
Warhead 146lbs (66kg) direct fragmentation with proximity/contact fuse
Length 4.3m
Diameter 23cm
Performance Speed Mach 1 +, range 93km, guidance passive radar seeker


Conclusion: As War Thunder progresses to the modern age, it will likely be necessary to include a form of self-defence against radar systems, which will require the need for anti-radiation missiles. The ALARM is Britain’s solution, one which must be added in it’s fullest capability.



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