interpreted the PIRAZ cruiser's AN/SPG-55 radar as a North Vietnamese SAM site. Worden required ten days shipyard work at the Subic Bay Naval Base to repair the damage. Although the Shrike missile did not enter regular service with the United Kingdom, it was covertly supplied by the United States to the RAF for use in the Falklands War of 1982. RAF Shrikes were fitted to modified Vulcan bombers in order to attack Argentine radar installations during Operation Black Buck. The main target was a Westinghouse AN/TPS-43 long range 3D radar that the Argentine Air Force deployed during April to guard Falklands' airspace. The Argentine operators were aware of the anti-radiation missiles and would simply turn it off during the Vulcan's approaches. This radar remained intact during the whole conflict. However, air defences remained operational during the attacks and the Shrikes hit two of the less valuable and rapidly replaced secondary fire control radars. After one Vulcan made an emergency landing at Rio de Janeiro, Brazilian authorities confiscated a Shrike which was not returned. About 95 AGM-45s were used in 1991 during Desert Storm against Iraqi air defense, mostly by F-4Gs. Variants There are many subvariants, each tuned to a different radar band. Angle gating, used to prioritize targets, was included in every subvariant of the AGM-45A and B after the A-2 and B-2. It was also slow and the lack of punch in the warhead made it difficult for bomb damage assessment, as well as inflicting any damage to the Fan Song Radar vans beyond a shattered radar dish, an easy item to replace or repair. The short range, combined with its lack of speed (compared to the SA-2 SAM) made for a difficult attack. The missile had to be well within the range of the SAM radar and if a SAM was fired the SAM would get to the aircraft first. Also the missile had few tolerances and had to be launched no more than + or − 3 degrees from the target. Many pilots in Vietnam did not like the Shrike because of its limitations and its success rate of around 25%. The differences between the AGM-45A and B are in the rocket motor used, and in the warheads capable of being fitted. The AGM-45A used the Rocketdyne Mk 39 Mod 0 (or apparently in some cases the Aerojet Mk 53 Mod 1) motor, while the AGM-45B used