How does any of that matter when it comes to a military tender? If the FC-31 v2.0 offers close to the same capabilities the J-20 does, and without breaking the bank, it should be a decent platform.
What I'm confused about is why the PLAAF/PLAN decided to reject the tender before the v2.0 (which is the full prototype rather than the 31001 tech demonstrator) has even debuted.
It's highly unlikely that the FC31 v2 will come close to J20 specs or capabilities.
There are very good reasons why the PLAAF went with the J20 over SAC's offering in the first place.
Not only is the J20 vastly ahead in terms of programme development, there are also key factors to consider beyond the state of the current prototypes.
Both the J20 and FC31 are flying with interim engines.
Whereas the J20's primary intended power plant the WS15 is getting priority status and appears to be making steady progress, there is no such next gen engine in the works for the FC31.
So even if the FC31 comes close to the J20's kinetic performance now, by the time they are both expected to mature into their intended versions, the J20 should blow the FC31 out of the water in terms of raw airframe performance.
A carrier J20 would require a substantial redesign, but then so would a carrier FC31.
Not only will a carrier J20 have superior raw performance compared to the FC31, it should also enjoy significant economies of scale savings in procurement, operating and training costs by sharing a common airframe and parts as the land based J20, much like how the F35 was supposed to deliver substantial economy savings for the same reasons.
The big difference would be that because there isn't a STOVL J20 to throw a spanner in the works, a Chinese joint stealth fighter programme between the Air Force and navy has a significantly better chance of achieving the kind of goals originally promised by the F35.
Even if the FC31 is significantly cheaper now compared to a J20, if you compare the total combined programme development, procurement, operating and training costs of a J20+FC31 programme against a two version J20 programme, I would be very surprised if the J20+FC31 combo deal will come out significantly cheaper overall.
The only real, solid advantage the FC31 has over the J20's is size, so you can fit more FC31s on a carrier than you could a carrier J20.
While there are merits to both arguments, all you have to do is look at past PLAN procurement choices to see which side they stand on when it comes to heavy vs medium carrier fighter.
The PLANAF had the very viable option of buy off-the-shelf Russian Mig29Ks rather than develop the J15. Alternatively, they could have opted for a carrier version of the J10B/C if they wanted to go the domestic medium carrier fighter route.
Instead they opted for the heavy J15.
The fundamental reasons for them to prefer heavy over medium would not chance, so it's little wonder that when asked again if they wanted heavy or medium, they opted for heavy again.
I think realistically, the only option for the FC31 is now export.
As the name suggests, it will become the Chinese fifth gen JF17/FC1 - a low cost 'good enough' fighter offering that China could sell for profits with minimal risk of allowing potential adversaries and foes to be able to gleam operationally relevant data that could be used to counter China's own fighter forces.
America can acquire entire squadrons of JF17 or FC31s for their aggressor squadrons and it won't make US pilots any better at being able to fight J10s or J20s if it really came down to it.
As China expands its role and footprint internationally, having a viable 5th gen fighter it could offer to friends and allies would be a powerful card to be able to play, so it may well be worthwhile for the Chinese government to part finance the FC31 so it could use it as a diplomatic tool, as well as to keep enough competition alive inside China's fighter market to stop CAC becoming the Chinese LockMart, with all the risks that comes with having a single over dominant player in any critical field.
