On 22 October the SADF airlifted more personnel and a squadron of Eland armoured cars to bolster UNITA positions at Silva Porto. Within days they had overrun considerable territory and captured several strategic settlements. The SADF's advance was so rapid that it often succeeding in driving FAPLA out of two or three towns in a single day. Eventually the South African expeditionary force split into three separate columns of motorised infantry and armoured cars to cover more ground. Pretoria intended for the SADF to help the FNLA and UNITA win the civil war before Angola's formal independence date, which the Portuguese had set for 11 November, then withdraw quietly. By early November the three SADF columns had captured eighteen major towns and cities, including several provincial capitals, and penetrated over five hundred kilometres into Angola. Upon receiving intelligence reports that the SADF had openly intervened on the side of the FNLA and UNITA, the Soviet Union began preparations for a massive airlift of arms to FAPLA.