Quickie
Colonel
The fact that over a hundred J-11Bs are flying with WS-10s is proof that the engine has already pass the test for operational use in the eyes of PLAAF. No military power would accept that half of the air force jets would be down with repair at any one time. If the WS-10 is that problematic, the PLAAF would have rather continued buying the J-11A/flanker kits including the engines from Russia and by now the PLAAF would have a bunch of Russian flankers instead of the J-11Bs.