The British Aerospace Sky Flash and the Alenia Aspide share a common heritage, both are based on the U.S. AIM-7 Sparrow.

Alenia Aspide

The AIM-7 Sparrow started life in 1946 as Project Hotshot before becoming operational in the early-1950's. The system was designed as a supersonic (Mach 4) all weather/all altitude medium range missile. It's primary guidance system utilises both the launch aircrafts own radar and its own dual radar receivers. One of these receivers is mounted in the rear to directly pick up the launch aircrafts own radar, while the second receiver in the front picks up energy reflected from the target aircraft. These two sources allow the missile to not only track changes in the target aircrafts position but also estimate its own closing speed. Detonation of the High Explosive Fragmentation warhead can occur via either a active radar proximity fuze or a secondary contact device.

Following the Vietnam War it was found that one noticeable limitation in the Sparrow's capability was engaging fast, manouverable targets. Subsequently a redesign lead to the AIM-7E2. It is upon this missile that both the BAe Sky Flash and the Alenia Aspide were based. However Sparrow modernisation did not stop at -7E2, development continued till the -7P in the early 90's. Further development to a new -7R standard was ceased in 1996.

Sky Flash and Aspide are very similar to Sparrow in construction, Sky Flash being just a little longer and wider. The missile can be divided into essentially five basic sections; radome/front receiver, guidance, warhead, flight control and rocket motor. These sections are wrapped up in an Aluminium based frame with four delta wings mounted centrally and four delta fins mounted at the rear. Like Sparrow, Sky Flash and Apside are semi-active missiles using the launch aircrafts own radar to illuminate the target and provide guidance. The major differences between AIM-7, Sky Flash and Aspide lay in the choice of propulsion, warhead and guidance. While the Sparrow series use Raytheon sourced receiver assemblies, Sky Flash utilises a Marconi XJ521 monopulse system and control software and Aspide uses a Selenia manufacturer radar receiver. Similarly the current generation U.S. Sparrow's use a Hercules rocket motor while Sky Flash uses a combination of Rocketdyne or Aerojet systems, Aspide utilises SNIA-Viscosa sourced solid motor.

The British Sky Flash entered service in 1976 aboard the RAF's fleet of F-4 Phantom's. In the mid-80's with the service entry of the Tornado F.3 ADV Sky Flash became its primary air defence weapon. The Royal Swedish Airforce also utilised Sky Flash for its own Viggen fighters. The Italian Air Force deployed Aspide in 1987 aboard its Starfighters. In addition Italy has deployed a number of Aspide variants such as the surface to air Skyguard.

The major pitfall of a semi-active weapon is the requirement to maintain positive radar contact with the target aircraft. Therefore the launch aircraft must remain in relatively straight and level flight during the course of the missiles run, which of course leaves the aircraft wide open for retaliatory attack. In the UK Matra-BAe Dynamics initiated the Active Sky Flash project to examine a next generation fully autonomous active missile which would negate these problems. Similarly Italy commenced a project to examine development of an Active Aspide. However both these projects were superceeded by joint American-European agreements on the co-development of next generation medium and short range missiles. Although these agreements ultimately failed (see ASRAAM for more details) the U.S. still produced its Sparrow follow-on, AMRAAM.

With the delayed service entry of Eurofighter the Tornado F.3 will remain in service well into the first decade of 2000. The Tornado F.3 is already at somewhat of a disadvantage being primarily an interceptor rather than a fighter. Leaving it armed with a 30 year old weapon would be an unnecesarry risk. Therefore it was decided in the late 90's to upgrade all Tornado F.3's to carry AMRAAM rather than Sky Flash. Within the next year or two the fleet upgrade will be complete and the operational requirement for Sky Flash will have gone.

The data below is a composite of both systems, they are physically quite similar so the data should be approximately correct for both

* : Note that all ranges quoted are based on mean figures from various data sources. Actual achievable range will depend on a great number of factors and may be no where near those quoted.