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COMAC C919 airliner is not the only example of China’s aviation industry taking parallel tracks in developing a Chinese-only version—with exclusively China-sourced components—of a design that is also available for civilian and perhaps export customers with imported components.
The AC313A (top) is evidently related to the Z-8L developed for the People’s Liberation Army (PLA). While very different from their ancestral origins, both are ultimately derived from the longstanding Z-8, which is the Chinese derivative of the 1960s vintage French Aerospatiale SA 321 Super Frelon. The PLA is unlikely to accept any aircraft with an imported engine, at least an engine that is not supplied by Russia (or, previously, Ukraine). As a result, the Chinese engineers assigned to the Z-8L project encounter constraints that their counterparts on the AC313A project do not, and the designs have, as such, diverged, with the visible differences to the top of the fuselage accommodating the engines likely to be but a part of a much bigger story independent of the military-specific design features of the Z-8L.
Such dynamics have a variety of implications. For one, it means that China cannot fully benefit from economies of scale for as long as there exist in parallel very distinct PLA-specification and commercial-specification designs, with the former making use of Chinese components. To state the obvious, there would be no market case for the AC313A—not outside an extremely competitive small market for large civil helicopters of this performance class—were a civilian version of the PLA-specification Z-8L a competitive offering relative to offerings from established vendors such as Sikorsky, Airbus Helicopters, and Leonardo Helicopters. If no one else, Chinese buyers, including Chinese state-owned enterprises engaged in offshore oil drilling—which are the main customers for large helicopters of this weight class—would be buying the Z-8L, not the AC313A or a foreign-built design from one of the aforementioned vendors. That said, it bears emphasis that the very existence of the Z-8L demonstrates that Chinese industry is capable of supplying the required components, even if—as with the C919—regulatory and/or sales and export competitiveness considerations drive Chinese industry to rely on imported components for the civilian versions that are often also offered to export customers and which must, as such, compete with the offerings of established vendors after receiving the approval of foreign regulators.