1984-1986 Ph.-D. Candidate at DLR. 1986-1990 Scientist at Subsonic Aerodynamics branch of DLR. 1990-1991 Guest Scientist NASA. 1991-1995 Scientist at Propulsion Integration branch of DLR. 1996–2001 Head of Configuration Aerodynamics branch of DLR. 1996–1997 Coordinator of DLR Research Programme ‘Propulsion Integration’. 1997–2002 Coordinator of DLR Research Programme ‘High-Lift’. 1997–2002 Coordinator of DLR Research Programme ‘Virtual Aircraft’. 1999 Guest Scientist ICASE, NASA-LaRC. 2001–2003 Head of Transport Aircraft branch of DLR Institute of Aerodynamics and Flow Technology. Since 2002 University Professor for Aerodynamics, TUB. Since 2003 Head of DLR Institute of Aerodynamics and Flow Technology. 2010-2020 Topic Speaker for DLR’s Fixed Wing Aircraft activities. 2013-2014 Acting Head of DLR Facility Flight Experiments; 2018 Acting Head of DLR Facility Flight Experiments. Since 2020 Topic Speaker for DLR’s Efficient Vehicle.