first embodiment fig3 shows a partially cut away side view of one ball screw actuator 70 in either the first or second embodiments in each embodiment there will actually be a second identical ball screw actuator present for each flap 30 in order to have a back up actuator in case the first should fail the ball screw actuator 70 comprises ball bearings 71 which fit into two sets of channels 72 formed between two internally threaded portions 67 a of the outermost rod section 62 and the externally threaded portion 67 b of the intermediate rod section 63 the ball bearings 71 fill up the two sets of channels and cause the intermediate rod section 63 to move in relation to the outermost rod section 62 fig4 shows a perspective view of the linkage system 80 90 100 in either the first or second embodiments the linkage system comprises three components an a link 80 a support bracket 90 and an i link 100 the a link 80 comprises an a frame 81 the a frame 81 is provided with two foot portions 82 83 extending behind the u201c a u201d shape from the bottom of the two legs of the u201c a u201d shape each foot portion 82 83 is provided with a hole 84 85 a pin 88 is located through bushes in the two holes 84 85 so that the pin 88 is parallel to but behind the bottom of the u201c a u201d shape the pin 88 is fixed between a pair of adjacent ribs 22 a 22 b at the leading edge of the aircraft wing 510 the a frame 81 can pivot around the pin 88 and so can pivot with respect to.