Yvan Du Monceau de Bergendael was born on 10 December 1915 at Fullham (London). He was at the Flying School (83rd Promotion 3 June 1939) at Tirlemont when war broke out. The school evacuated to Morocco. There with some fellows he escaped to the UK. He completed his training at the Suton Bridge OTU and joined  253 SQN . In April 1941, he was posted to 609 SQN. He became flight commander with 350 (BELGIAN) SQN in March 1942. There he was awarded a DFC in July 1942. From December 1942 till May 1943 he was instructor at the OTU in Rednal. He then took command of 349 (BELGIAN) SQN, which was newly-formed. He received a Bar to his DFC and was posted to Canada, then in the US and returned in Europe in 1945 at the Staff of the Belgian Section of the RAF. He became Aide de Camp of his HRH Prince Charles , Regent of Belgium with the rank of Major. He acted then as Military Attaché in Washington and returned to Belgium in 1952 to form the 10th Wing at Chièvres. He went to the 2 ATAF as Colonel . He Became Staff member, Commander of Training Command and finally Commander of the Tactical Air Force, retiring as Major General in 1973. He died of cancer on 9 November 1984.