In this respect, CJ1000 and WS-20 are the same, SF-A was initially considered as the engine of C919. If the WS-20 needs to restart testing on the C919 for 2.3 years, the same is true for the CJ1000 after the forensics are completed. It takes 2 or 3 years of testing to replace the c919 with the CJ1000. That means it won't be put into use until at least 2030. And this requires a major premise. CJ1000 must be completed strictly according to COMAC's schedule, but COMAC's record has been poor in this regard.
If you want to make a case for developing a domestic C919 variant with WS-20, that is fine, but you need to understand that it is not a clear and cut case of "just go for it".
The rational for developing a C919 variant with WS-20, is dependent on a range of factors, such as:
- When a C919 with CJ-1000A is expected to emerge
- The actual performance of a C919 with WS-20 in the first place
- The priority of having a domestic C919 variant in the first place
- The availability or non-availability of purchasing foreign narrow body airliners
- The importance of having a steady stream of narrow body airliners in context of the national geopolitical strategy
There are a few circumstances I can see where developing a C919 with WS-20 intended for the civilian market may be necessary.
For example, if CJ-1000A is simply unable to bear fruit until after 2035, and if for example the US and Europe tomorrow cut China off entirely from purchasing narrow body airliners, parts, engines and support wholesale, resulting in a fixed expiry date of China's national narrow body airliner fleet that has to be plugged with a similar aircraft, as judged to be important by national leadership.
Then sure, C919 with WS-20 is certainly much better than nothing.
But other than that, I don't see a scenario whereby C919 waiting for CJ-1000A is unacceptable and where integration of WS-20 is somehow vital to the survival of the aircraft program.