Future Air Traffic Control Officers (ATCOs) will have to monitor closely whether aircraft are compliant with given time constraints. This time- based guidance will be a new task compared to current operations where the timely precise adherence to flight plans is not a high priority. This additional requirement will produce new task loads, especially in approach control, where the main task of the ATCOs is to implement conflict-free optimized landing sequences with aircraft of different performance characteristics and wake vortex classes. It is anticipated that from medium traffic load on, the task load will increase to a level that ATCOs couldn't cope without the use of decision support tools (DST). They may even be forced to delegate the time-constraint monitoring completely to the automation. In the DLR project Aviator II a usability study was conducted to evaluate an advanced arrival management system that behaved adaptive to the workload apperception of ATCOs. In three sessions a SME (subject matter expert) worked on a medium traffic scenario with the support of this adaptive DST. After a training and a test run, the SME filled out a usability questionnaire with a focus on the adaptive functioning. The paper describes the concept and implementation of the adaptive DST and summarizes first results regarding the potential benefits of such an innovative feature in a controller working position.