 Johnson exited the mass of aircraft and was immediately attacked by three Bf 109s . The closest was 100 yards away . Maintaining a steep , tight , spiralling turn , he dived into cloud and immediately headed for Dover . Coming out of the cloud , Johnson saw a lone Bf 109 . Suspecting it to be one of the three that had chased him , he searched for the other two . Seeing nothing , Johnson attacked and shot it down . It was his fourth victory . Johnson ended his month 's tally by adding a probable victory on 21 August . But it had been a bad day and month for the Wing . The much loathed Circus and Rhubarb raids had cost Fighter Command 108 fighters . The Germans lost just 18 . On 4 September 1941 Johnson was promoted to flight lieutenant and awarded the Distinguished Flying Cross ( DFC ) . 
