Maybe it is a unit redeployment? Probably they decided that only aircraft and pilot and some other important equipment and personal need to move when something like local air base assets and some of logistic crews (those who doing something like supply food for the base) stay thus the OOB would remain same when their major equipment changes. IIRC US Army have done something similar to their european garrison.
Interesting ... but even more interesting, that a few (indeed most) J-11Bs in that line-up have a grey radome similar to the J-15s !!
Deino
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Do you think the inevitable radar upgrades will impact J-11B/BS/A?