Colonel Kortleven joined the BAF in 1971. After an Undergraduate Pilot training, 800 hours on Mirage 5 and 3 years as flight instructor on T-33 and Alpha Jet, he did his F-16 conversion in 1981.
After 1 year in the 349 Sqn at Beauvechain, he was posted to 23 Sqn Kleine Brogel.
After a staff tour from 1987 till 1990 he was CO of 23 Sqn untill 1992. After several other desktours he became Flying Group Commander 10 Tac Wing Kleine Brogel from 1999 till 2001. During that period he was CO of the DATF at Amendola from April untill July 2000.
2003: Presently he is part of the Reaction Force Air Staff (RFAS) at Kalkar. His total hours on F-16 is 1500 hrs, on all the A/B types from Block 1 to MLU included.