on 7 september 1940, no. 605 moved on rotation to croydon aerodrome under the command of squadron leader walter churchill. mckellar scored a further four victories in a single mission on 9 september. mckellar attacked with the sun at his back with his squadron, save for one section which was left to provide top cover against bf 109s. the attack was made head-on to break up the german bomber formation which consisted of a large mass of he 111s. he destroyed three he 111s with a single, 12–second burst. the first he 111 exploded. it damaged a second which rolled over and dived down into the ground. mckellar then moved his fire to a third. its port wing snapped off. he then destroyed a bf 109 in the afternoon giving him a fourth success.