Pakistan got 200 russian engines via china on the condition of no sale to third country.Each machine requires 2 engines, this gives Pakistan 100 machines.50 have been delivered/inducted, the remaining 50 will be completed by the middle of 2016.By that time WS-13/17 Engine will be ready for JF-17 block 3 with aesa radar.Since Chinese do not allow Pakistan sell the aeroplane with any other engine ,Export and remaining PAF requirements will then begin.This is my cumulative assessment based upon continous following of JF-17 wprogram since 1992.Only AERONAUT can provide you with authoritative info.