A senior executive at Russia’s state arms export company, Rosoboronexport, has said that Russia will sign a contract to sell the advanced Su-35 jet to China in 2014, while confirming that the deal is not on track to be finished in 2013. This is unlikely to be the last word on the matter – the negotiations have dragged on since 2010, and have been the subject of premature and contradictory announcements before – but it is a strong indication that Russia remains interested in the sale. For the time being, China’s interest in the new-generation fighter is worth examining for what it reveals about the progress of homegrown military technology and China’s strategy for managing territorial disputes in the South China Sea. If successful, the acquisition could have an immediate impact on these disputes. In addition to strengthening China’s hand in a hypothetical conflict, the Su-35’s range and fuel capacity would allow the People’s Liberation Army Naval Air Force (PLANAF) to undertake extended patrols of the disputed areas, following the model it has used to pressure Japan over the Diaoyu/Senkaku islands.

The Su-35 is not the first Sukoi to pique the interest of the Chinese military. As previously reported in The Diplomat, the Sukoi-30MKK, and the Chinese version, the J-16, have been touted by the Chinese military as allowing it to project power into the South China Sea.

Previous reports in Chinese and Russian media in June of this year pointed toward a deal having been reached over a sale of Su-35 multi-role jets, but were not viewed as official, given more than a year’s worth of contradictory reports in Chinese and Russian media. At one point, Russian sources claimed that the sale had gone through, only to be categorically refuted by the Chinese Ministry of Defense. Nevertheless, in January both governments paved the way for an eventual sale by signing an agreement in principle that Russia would provide the Su-35 to China.

A big question remaining is the number of aircraft that China will purchase. China’s Global Times reported this summer that a group of Chinese representatives were in Moscow evaluating the Su-35, and would begin acquiring a “considerable number” of the advanced jets. Whether that means that China will purchase more than 48, as mentioned in press statements a year ago, is unclear. Evidence of continued negotiation for the jets indicates a strong desire within the Chinese military to acquire the Sukhoi fighters.

Chinese aviation is still reliant in many ways on Russia. Media attention has focused on China’s domestic development programs, including stealth fighter-bombers and helicopters. The advance of Chinese aviation capabilities is by now a common theme, with every month seeming to bring new revelations about its programs. While the ability to manufacture and perform design work on these projects represents significant progress, “under the hood” these aircraft often feature Russian engines. China continues to try to copy or steal Russian engine technology because of a strong preference for building systems itself. In fact, purchasing the Su-35 does not reflect a shift in the preferences of the Chinese military leadership. Buying the Su-35 reflects the delicate position China now finds itself in, as both a large purchaser and producer of primarily Russian-style weapons. Though self-reliance has always been important to China, it has been superseded by the strategic need to acquire cutting-edge weapons systems quickly. According to data from the Stockholm International Peace Research Institute (SIPRI), beginning in 1991, China began purchasing the Su-27 long-range fighter jet (an older relative of the Su-35). The data is searchable here.

Russia understandably became upset when its star export appeared as an indigenously produced J-11 in China – without a licensing agreement. Russian media was previously reporting that Russia had chosen not to sell the jet over fears that it would be copied in turn and become yet another export item for China, further undercutting Russia’s own economically vital arms business. It appears that now Russia is trying to balance its fear of being undercut by Chinese copying with its desire (or need) to sell weapons.

Viewing the purchase of the Su-35 through the lens of China’s strategic needs and events, like the recent territorial spats with its neighbors, provides a useful perspective on just why China is so eager to acquire the Sukhoi jet.

Simply put, the Su-35 is the best non-stealth fighter in the world today. Though stealth has come to dominate Western aircraft design, in terms of China’s needs, other factors take precedence. Even more surprisingly, superiority in air-to-air combat is not the Su-35’s key selling point. while the Su-35 gives the Chinese military a leg up versus the F-15s and other aircraft fielded by neighbors like Japan, the advanced Russian jet does not add significant new capabilities to conflict areas like the Taiwan Strait. Large numbers of interceptors and multi-role jets like the J-10 could easily be deployed over the Strait, or to areas near Japan like the Senkaku/Diaoyu islands. The advantage of the Su-35 rather lies in its speed and ample fuel tanks. Like the Su-27, the Su-35 was created to patrol Russia’s enormous airspace and to be able to meet incoming threats far away from Russia’s main urban areas. The People’s Liberation Army Air Force (PLAAF) faces similar problems.

The South China Sea is just such a problem. A vast area of 1.4 million square miles (2.25 million square kilometers), China’s claims, as demarcated by the famous “nine-dashed line,” pose challenges for the People’s Liberation Army’s (PLA) current fighters. Currently, land-based PLANAF fighters, can conduct limited patrols of the sea’s southern areas, but their fuel capacity severely restricts the time they can spend on patrol. Enforcing claims far from the mainland in times of crisis requires the type of range and speed that the Su-35 possesses. The Su-35 is likely meant to help enforce China’s territorial claims, further deter regional claimants, and provide additional layers of protection in the case of escalation. The key to this is fuel.

One important improvement of the Su-35 over the Su-27/J-11B is the ability to carry external fuel tanks, be a major factor limiting the Su-27, which does not have aerial refueling capability. This is in addition to a 20 percent increase in fuel capacity over the Su-27 and air refueling capability. This later capability is another important part of China’s strategy of increasing loiter times and distances. “Loiter time” is the time an aircraft can spend in the vicinity of a target, as opposed to reaching the area and returning to base. Generally there are three ways to increase loiter time. Smaller, slower aircraft like the U.S. Predator or global hawk drones can stay aloft for many hours at a time because of their long wings and lack of a pilot. The other two options are larger fuel tanks or refueling capability. China’s nascent aerial refueling program is not yet fully proven and does not currently involve any naval planes, and is estimated at becoming operationally effective between 2015-2020 in Chinese Aerospace Power: Evolving Maritime Roles.

The Su-35, even on internal fuel only, offers significant advantages over the Su-27, which is limited to only quick fly-overs of trouble spots such as the Reed Bank (lile tan) or Scarborough Shoal (huangyan dao). The extra time the Su-35 can spend on station is essential to China’s desire to deter action by the Philippines or other regional actors. Such long-range aircraft would be able to “show the flag” for longer, or quickly intercept Philippine aircraft in the region. In the case of the Su-35, it would likely be able to outfly and outshoot any Philippine or Vietnamese aircraft (or surface vessel for that matter) largely rendering competing territorial claims irrelevant.

This is the sort of fait accompli situation that China has sought to create, for example with the “eviction” of the Philippine presence from the Scarborough Shoal and repeated fly-bys of the disputed area in the East China Sea: an overwhelming Chinese presence around territorial claims, leaving the contender with the options of significantly ratcheting up tensions and likely losing any skirmish or accepting a regular Chinese military presence. With the ability to make extended flights over a larger portion of the South China Sea, the PLANAF is likely to increase air patrols. This could lead to more frequent encounters in more places, creating more opportunities for minor crises and allowing China to create new “facts on the ground,” which may serve as the starting point for negotiations in a peaceful settlement. This capability, combined with China’s already significant ballistic missile forces and other anti-access weapons, provides China with a significant trump card and thus acts as a deterrent to military challenges. This gives China the ability to project military power over a larger portion of Southeast Asia and indeed, most of the ASEAN nations.

Beyond deterrence, a jet with a longer-range purchases more than just loiter time. Areas like Hainan are more vulnerable to attack by cruise missile or carrier-borne elements than those behind the prickly hedge of China’s air defense systems. Overlapping radars, shorter ranged interceptors and powerful surface-to-air missile systems make deploying aircraft to the mainland an attractive option. With its extended range however, the Su-35 should have little trouble flying from behind coastal areas to a large portion of the South China Sea.

Land-based, long-range patrolling Su-35s are one of the best ways to ensure that China retains the ability to restrict other contestant nations’ access to these areas. This has become even more urgent now that the U.S. has announced plans to deploy the F-35 into the region, likely to important bases in Korea and Japan.

In the meantime, while the U.S. and its allies face a potential gap in capabilities between aging airframes and delivery of the F-35, China is rapidly phasing out older platforms, upgrading legacy systems and trying to acquire newer aircraft. The Su-35 is a major step in this direction.

While not on par with the U.S. F-22, the small numbers of that platform and risks of deployment make the Su-35 likely superior to anything readily deployed in the region for some time. Moreover, though the Su-35 is much more agile than the Su-27, similarity between the Su-35 and earlier Sukhoi platforms should mean less effort expended building a new logistics tail and retraining, leading to faster operational status and deployment. There are no clear indications whether the PLAAF or PLANAF would use the Su-35s, but deployment to the PLAAF Air Base in Suixi, Guangdong (Yuexi Airport) part of the 2nd Division in Zhanjiang, Guangdong (Unit 95357) would complement the other Su-27s already stationed there. The PLA Naval Aviation base at Lingshui, Hainan province (famous for being the airport where a U.S. EP-3 surveillance plane performed an emergency landing in 2001) is another useful option for basing. The Su-35s could replace the rapidly aging J-8Bs and Ds currently based there.

While the Su-35’s technologies will benefit Chinese aviation, its larger contribution lies in enforcement and deterrence in the South China Sea. China’s currently deployed forces in the South China Sea and contested areas could already do significant damage to possible adversaries like the Philippines. Without a combat-capable air force and naval forces largely comprising aging 1960s-era former U.S. Coast Guard cutters, the Philippines cannot effectively challenge China’s territorial claims. The Sukhoi jets’ larger fuel capacity and in-flight refueling capability mean that Chinese jets could remain on station for longer, enforcing their claims by conducting patrols and interceptions in a more consistent way. Going forward, the combination of the Su-35, China’s extant shorter-range fighters, advanced surface-to-air missiles, and long-range ballistic and cruise missiles could provide strength-in-depth, multi-layered capabilities to protect China’s claims and make others less eager to intervene if China chose to pursue conflict with its neighbors.

Peter Wood is an independent researcher focusing on the Chinese military. A longer version of this article appeared in the October 10, 2013 issue of the Jamestown Foundation’s China Brief.