2 hours 15 minutes could be enough to make this connection -- but only if everything works perfectly. You will need to leave the plane. collect your bags, walk to the check-in lines for the SA flight, check in and get your boarding pass, and then go through passport control and security before reaching the departure gate. If your flight is late for any reason or if there are unusually long lines for check-in, passport control or security screening you could indeed miss your flight to JNB.