Air defense missile: As a first-level destroyer focusing on air defense, the 171 is equipped with China's first ship-based long-range air defense missile, model "HHQ-9", which was developed from the land-based HQ-9A. Come. The missile is wingless, with a minimum combat altitude of 0.5 kilometers, a maximum combat altitude of 30 kilometers, a minimum combat range of 6 kilometers, a maximum combat range of 120 kilometers, and a maximum flight speed greater than Mach 4.2. The missile has a total length of 6.8 meters, a diameter of 0.47 meters, a weight of 1,300 kilograms, and a warhead weighing more than 180 kilograms. The missile launch method is vertical cold launch, 6-pack, with a total of 48 HHQ-9A missiles. The launch tube is similar to the revolver type used by the Russian Navy, but the SA-N-6 launch system uses one launch port for eight missiles, while China's Haihong-9 uses a separate launch port for each missile. In comparison, the launch method of Haihong-9 is more reliable, the launch speed is faster, and the safety rate is also high. However, since the minimum firing height of this missile is only 500 meters, it is obviously unable to meet the requirements of fleet air defense. Therefore, the close cooperation of other ships is required when performing formation air defense.