Why don't you enlighten us oh wise master? Don't get your knickers in a twist, the fact that the ZDK03 was produced in such low numbers, was never inducted by the PLAF, and with the PAF the only operator, it meant a high risk for the PAF, clearly it looks like they didn't like that risk anymore.
1. The first ZDK-03 AEW&C aircraft was delivered to the PAF in 2011.
At that time, the only AEW&C platforms in service with the PLA itself were the KJ-2000 and the KJ-200. The KJ-2000 was too large and prohibitively expensive, making it clearly unsuitable for the PAF. The KJ-200, by comparison, was technically inferior to the ZDK-03.
Consequently, at that juncture, the ZDK-03—the system China provided to the PAF—represented the very best product available.
2. By that time, development of China's KJ-500 was already underway. Indeed, it could be said that certain technologies incorporated into the KJ-500 were validated through the ZDK-03 program. The KJ-500 stands as China's first truly mature AEW&C platform; whereas the KJ-2000 and KJ-200 saw only limited production and deployment, the KJ-500 was the first to undergo genuine mass production and widespread deployment. However, the KJ-500 did not complete its maiden flight until 2014 and did not officially enter service until 2015.
At the time, the PLA could afford to wait for the KJ-500 to reach maturity, as it already had the KJ-2000 and KJ-200 in active service; the PAF, however, may not have had that luxury.
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Technical risks and opportunities often go hand in hand.
Investing during the early stages of technological development means reaping technological dividends sooner, but it also entails technological risk.
Investing once the technology has matured means your technological risk is very low, but it also implies that it will soon become obsolete.
The J-10 series fighter jets: The PAF did not begin procuring the J-10CE until the platform had reached full maturity. This implies that the PAF faces virtually no significant technical risks. However, China has already initiated the process of phasing out this aircraft. Consequently, China will not undertake any major upgrades or updates to this fighter jet in the future. Furthermore, a decade from now, issues regarding the supply of spare parts for maintenance are likely to arise.
The same issues apply to the FC-31/J-35 and other weapon platforms as well.