ALARM compromised in Yugoslavia

25 May 2001

ALARM compromised in Yugoslavia

The Air-Launched Anti-Radiation Missile (ALARM), the Royal Air Force’s highly capable weapon for suppressing enemy air defences, has been compromised in Yugoslavia. That is the pessimistic conclusion that must be drawn from the fact that an almost completely intact example is now on display in the Belgrade Military Museum as reported in the May issue of Jane’s Missiles and Rockets.

According to one Yugoslavian source, the missile in question – fired during Operation ‘Allied Force’ last year – was found just outside the village of Nikinci in western Serbia. The ground in that region is considerably marshy, which may have contributed to the missile being found essentially intact.

There are now questions of obvious concern to the Royal Air Force, NATO and the manufacturer, Matra BAE Dynamics:
· Did the weapon fail to self-destruct and, if so, why?
· How much have Yugoslav engineers been able to learn from from studying the recovered seeker head?

ALARM was not a commercial success following its initial appearance in 1990, and only the UK and Saudi Arabia have procured it. However, it was designed a decade later than the equivalent US AGM-88 HARM and has shown itself to have several advantages over its US rival. According to one senior serving aircrew officer, US and German aircrew fired around 100 HARMs at a particular Yugoslavian target without success, and the Royal Air Force finally destroyed it with a single ALARM.

Although at first sight this may seem unlikely, it is partly a function of tactics and partly a function of the different design philosophies of the two missiles. Yugoslavian sources report that defences are able to deploy Russian-developed emitting decoys designed to counter HARM, and that the netting of multiple emitters and passive sensors allows the target illumination time of a surface-to-air missile (SAM) battery to be reduced by between 50-70%.

If the enemy shuts down quickly, HARM is unable to find its target. This leads commanders charged with the suppression of enemy air-defence (SEAD) mission to fire a steady stream of missiles (all effectively on a predictable, relatively short time-of-flight trajectory) in order to create a ‘HARM umbrella’.

A single ALARM can loiter at high altitude, remaining in the area of the emitter for some time. Since it was originally conceived primarily as a self-defence weapon for aircraft – some of which might not have a radar-warning receiver – all the ‘intelligence’ is on board the missile, making the weapon very flexible and difficult to spoof. This capacity of ‘intelligent’ loiter for corridor ‘sanitisation’ and SAM harassment tasks made ALARM the anti-radiation missile most feared by Yugoslav SAM crews.