These things tend to hang around........

Weapon performance remains a sensitive topic even after withdrawal from service so you won’t (or at least, shouldn’t) get much of an answer on here, certainly on trial data. What I will say is that assessing its effectiveness on live operations was very difficult: as a long-ranged and quite slow-acting missile it did its business well out of sight, and no-one wanted to hang around near air defence systems to see what it was up to. If no-one got shot down while an ALARM was in the air, was that because it scared the SAM operators into turning their radars off, or destroyed the radar, or simply because no-one would have been shot down anyway? A great imponderable. HARM was/is different in that regard because it did/does its business quickly (the clue is in the name...) and so is perhaps easier to correlate a shot with an outcome. Enough said I feel.

The 'loitering' capability under the 'chute really drove the design of the weapon. Getting a burnable chute out of the back of rocket motor was quite a trick. The warhead also had to be quite nasty to achieve effects from a missile that was designed not to directly hit the emitter.

Arguably its best feature was when used in tandem with HARM capable aircraft, giving the SAM crews quite a complicated picture. Add in the odd LO platform and some jamming, both stand-off and stand-in and the overall effect was rather good.

The worst feature, especially when not operating in a mixed package was the speed of the thing. More of a SARM than a HARM, to the point that it was easy to arrive over the target well before the missile you fired earlier.


As ever, no comments on the EW side as those elements live on even after the demise of the missile.

BVRAAM,

Open source data such as that found in Wiki are all you’ll get (or again, should get!). One very good reason for continuing to protect such data after a piece of kit is retired is that the data could serve to prove the credibility of sources who may have leaked information while the kit was still in service. As those sources may still be active then there is a clear imperative to avoid corroborating their earlier tales. Or, indeed, to avoid exposing sources of deliberate misinformation!

With respect to the ex-Weasel, ALARM was a very different beast to the weapons he would have used. As mentioned by others above, ALARM had loitering and other modes that did not need the SAM to be provoked into action immediately. Hence most of the tactics and effective ranges bore little resemblance to those used with HARM and its predecessors.

​​​​​I was the desk officer in Operational Requirements for Alarm many moons ago! It was early days for defence suppression! There was a competition for the contract and to beat Texas Instruments with Harm, British Aerospace designed all sorts of extras into it! A two stage motor and the loiter capability for instance! Needless to say, M Thatcher thought the contract should go to a U.K. company! On her insistence, it was the very first Fixed Price Contract with British Aerospace! It was some months before they admitted that the motor was a problem! Eventually, as I recall, the contract came in at twice the price and took twice as long before delivery! Just thought you might be interested! Needless to say, M Thatcher was not impressed and my director had to fend off some flack from Number Ten!

Now of course you do it with drones. A small swarm to loiter in the area in orbit for several hours, just waiting for the radar to go active.....

https://en.wikipedia.org/wiki/IAI_Harop

Oh, that nothing compared to what’s in the pipeline.....