The confirmation last week that China has purchased between four and six battalions of the Russian-made S-400 air defense system has sparked alarmism in many circles, with experts stating that the new missile will allow China to strike aerial targets over major Indian cities, all over Taiwan, as well as within disputed areas in the East and South China Sea. But before we start calling the S-400 a “game changer,” a few comments are in order.
Rosoboronexport, Russia’s state-run agency in charge of export of defense articles, announced on April 13 that Moscow had agreed to sell China four to six S-400 battalions for the sum of approximately $3 billion. The confirmation ended years of speculation as to whether Russia would agree to sell the advanced air defense system to China, a “strategic partner” that on some occasions has bitten the hand that feeds it, advanced weaponry by reverse-engineering Russian products and producing copies—some intended for export—for a fraction of the price.
The contract was presumably signed in the last quarter of 2014, with delivery of the S-400 to be completed in 2017.
Soon after the announcement, security analysts started portraying the acquisition as a potential game changer. In an April 18 report, Defense News noted that “The 400-kilometer-range system will, for the first time, allow China to strike any aerial target on the island of Taiwan, in addition to reaching air targets as far as New Delhi, Calcutta, Hanoi and Seoul. The Yellow Sea and China’s new air defense identification zone (ADIZ) in the East China Sea will also be protected. The system will permit China, if need be, to strike any air target within North Korea.”
Citing Vasiliy Kashin, a China defense specialist at the Centre for Analysis of Strategies and Technologies in Moscow, the article added that that S-400 would “also allow China to extend, but not dominate, the air defense space closer to the disputed Japanese-controlled Senkaku Islands in the East China Sea.” Alexander Huang, a Taipei-based defense specialist, also told the publication that the system would “challenge Taiwan’s ability to conduct air defense operations within its own ADIZ, which covers the Taiwan Strait.”
Another analysis stated that the S-400 would allow China to “command the skies over the disputed Senkaku/Diaoyu Islands in the East China Sea.”
The problem with all this analysis is that it is undermined by the many unknowns that continue to surround the acquisition. For one thing, we do not know which type of missile the Russians will sell to the Chinese for the S-400 system. The 40N6 does have a purported operational range of 400km, but as Roger Cliff of the Project 2049 Institute told The Diplomat, it is not yet clear whether it is even operational in China, let alone that it is available for export. An alternative to the 40N6 would be the 48N6 series, whose range is much more limited, at 250km.
So unless China parks all its S-400 batteries right along the coast or its borders, and even if we assume that Moscow would agree to sell the 40N6 missile, it would be very difficult for the new SAM system to cover all the cities and areas listed in the reports. The Senkakus, for example, are located 200 nautical miles (370km) east of the Chinese mainland, thus at the very edge of the maximum operational range of the 40N6. The distance between New Delhi, another city named in the reports, and the Chinese border is about 400km; moreover, to bring the Indian capital within range, not only would China need to deploy the S-400 right at the border—a not uncontroversial move—it would have to perform the difficult feat of deploying the system…in the middle of the Himalayas!
In order to bring all of Taiwan’s airspace within range, the S-400 would have to come equipped with the 40N6 (a 250km range would be insufficient to meet this requirement) and it would have to deployed along the coast of Fujian, right across from Taiwan (at its narrowest, the Taiwan Strait is 130km wide; Taiwan’s width is 144km). However, deploying the system at sea level would impose severe restrictions. As Cliff, who co-authored a key RAND report on the PLA Air Force a few years ago, explained, a radar situated at sea level cannot see anything below 12,000 feet when it is 250km away. That’s simple physics—the earth is round. To improve targeting performance, the system would therefore have to be moved further inland and positioned on elevated ground (a 2,000-foot slope would enable a radar to see targets all the way down to sea level out to 100km).
Another limitation is the lethality of SAMs at maximum range, especially against maneuvering targets. “The main engine of anti-air missiles (surface-launched or air-launched) burns out after a few seconds. After that the missile is coasting, although it can still maneuver,” Cliff said. “If the maximum distance a 48N6 missile can fly is 250km, the odds of it actually intercepting its target at that range are pretty minimal, unless the target flies straight and level the whole time.”
“In other words, the effectiveness of the 48N6 in much of Taiwan’s airspace, except perhaps the northwestern part of the island, is questionable,” he said. The same principles of physics, of course, apply to the other purported targets mentioned in the recent analyses.
While the 40N6 would address most of those problems, it would create a set of new ones. Among them is the fact that full SAM coverage of Taiwan’s entire airspace would threaten Chinese aircraft during hostilities. Therefore, to make sure the S-400 does not engage in fratricide (i.e., shoot down PLA aircraft), Chinese planes would have to “stick to certain predefined ingress and egress corridors” in a missile engagement zone that extends into, and probably not beyond the median line dividing, the Taiwan Strait (see RAND report, pp. 212-13). Beyond that, in order to engage aircraft from the Taiwanese air force, PLAAF aircraft would need to have the ability to maneuver freely, at which point Chinese radars would have difficulty telling friend from foe.
“Would the PLA really want nasty surface-to-air missiles flying around in the same airspace where its own aircraft were operating?” Cliff asked, adding that the only two aircraft the U.S. Patriot system has ever shot down in combat were both friendly.
“That would mean that the S-300s, S-400s, and HQ-9s would not engage targets beyond a certain distance from China’s coast,” Cliff said, which suggests that the S-400 is intended for defensive purposes rather than the (“offensive”) interdiction of airspace over foreign countries or contested territories. Simply put, the PLA does not need the S-400 to perform such a task.
The Taiwan scenario discussed above highlights the similar problems that the PLA would encounter were it to utilize the S-400 in an offensive manner against other countries within the region.
Based on all this, it is rather clear that the ability of the S-400 to threaten China’s neighbors has been much overblown and is highly contingent on where the battalions will be deployed. At this point, we simply do not know, and all the brouhaha rests on the assumption that Beijing intends to use the system as an offensive air defense system. Much more likely, the PLA will deploy the S-400s near high-value targets across China such as major urban centers, major military bases, and so on, as part of its ongoing—and perfectly legitimate—efforts to improve the defense of its airspace.
As the delivery date approaches, let’s see where the PLA positions the S-400s. My bet is that we won’t see them along the Chinese coast or right across the border with neighboring countries.
Disclosure: The author is an employee of the Thinking Taiwan Foundation, a think tank launched by Tsai Ing-wen in 2012. The views expressed in this article are the author’s alone and do not necessarily reflect the official positions of the institutions with which he is affiliated.