The publication of images of a new configuration of China’s J-10 single engine fighter has sparked widespread speculation regarding the aircraft’s purpose, how widely it will be fielded, and what the spine itself houses. The J-10 is a lightweight combat jet currently in production on a larger scale than any other in the world, aside from the American F-35, with the newest variant the J-10C considered a close contender for the title of the world’s top single engine fighter. The aircraft is prized for its low maintenance needs and operational costs, its powerful AESA radar and network centric warfare capabilities, and its access to advanced weapons classes such as PL-15 air to air missiles. The newly revealed J-10 notably uses the older Russian AL-31FN engine, which has been phased out of new production batches in favour of the indigenous WS-10, indicating that it may be intended as an upgrade package for older J-10 variants or else that China’s Air Force is seeking to conserve the newer engines for production aircraft rather than prototypes.
One theory for the new aircraft’s purpose is that the expanded spine houses fuel for a smoke generator pod, allowing it to operate in support of older J-10s under the 72nd Air Brigade which also use AL-31FN engines. Another is that the aircraft may not be intended for Chinese service at all, but rather for an export client similarly to how American F-16Ds were modified with expanded spines for a number of foreign operators. Pakistan is the only confirmed export client for the J-10, having received its first fighters in March, although other clients most notably Iran have been speculated. Whether for export or domestic use, the package could carry new features such as an electronic warfare countermeasures jammer. The possibility of a fuel tank has also been speculated, although the relatively small size of the spine means it is unlikely to be well suited to this. The possibility that the spine as an export feature, if successful, could be implemented on future J-10s built for Chinese service, also cannot be ruled out. The spine may also be part of an upgrade package currently being tested to upgrade older J-10A and possibly J-10B variants to partly bridge the very significant performance gap with the new J-10C.