In 1935 he became a pilot with the Center of Aeronautics in Villacoublay (Centre d'Essais des Matériels Aéronautiques - CEMA) and took part in flight testing of the Morane-Saulnier MS.406, Dewoitine D.520 and Bloch MB.152.

[2] In December 1943 Rozanoff immigrated to the United Kingdom where he was promoted to lieutenant colonel and attended additional test pilot courses, including one at the Central Flying School.

During this time, Rozanoff flew the first Royal Air Force jet, the Gloster G-41, and participated in testing the P-59 Airacomet and the Lockheed P-80 Shooting Star in the United States.

[4][5][6][7] In 1954 Constantin Rozanoff published his autobiographical- Double Bang - Ma Vie de Pilote d'Essai.

Later, same year, Colonel Rozanoff was killed in a crash of a Mystère IV B during a public low-level flight over the Melun Villaroche Aerodrome.