The medi-evacuation flight was flown from Lanseria Aerodrome to Ondangwa (fuel stop) and on to Kinshasha. The pilot indicated that they were initially cleared for an ILS, VOR approach on RWY24, but noticed heavy rain in the threshold area of the runway. They requested a visual approach on RWY06 and it was granted. When the aircraft touched down it suddenly veered to the left of the runway and the left-hand landing gear collapsed. The aircraft skidded a distance over the runway surface and came to a halt on the left side of the runway.