コンゴ動乱
Between 1945 and 1956 von Rosen worked in Ethiopia as the chief instructor for the Imperial Ethiopian Air Force. Afterwards von Rosen was employed by the Swedish charter airline Transair. The company was engaged by the UN during the Congo Crisis 1960. Von Rosen also served as the pilot for the second Secretary-General of the United Nations, Dag Hammarskjöld. However, von Rosen was grounded by illness when Hammarskjöld was killed in an air crash while mediating in the Congo Crisis.