Optimization of Regulated Airline Arrival Flows via Target Time Management

Growing Air Traffic Flow Management (ATFM) delays emerge within the European Airspace. Solutions to mitigate their impact are researched and implemented by all airspace stakeholders. Target Time Management (TTM) is a proactive form of arrival sequence steering via Calculated Take-Off Times which could improve operational performance. This process is researched at SWISS, with an optimizer which outputs a wished arrival sequence every 60 minutes for Zurich arrival regulated flights. This sequence is sent to EUROCONTROL’s slot allocation algorithm (CASA), which takes into account the wished Target Times of Arrival. The optimization’s goal for the summer was to improve passenger connections without hampering rotation delays. Over the course of around two months, critical connections were improved by a weighted average of 6.2 minutes, without worsening rotation delays (a negligible improvement of 0.9 minutes was measured). A total of 3,879 flights and 72,730 connecting passengers were affected by the tool during this time. This proves the usefulness of TTM as a tool to improve operations under ATFM regulations. Yet, insights on the behaviour of CASA should be further modelled within the decision-making process. For instance, it was found that requesting a delay typically results in higher acceptance rates than asking for an anticipation (81.6% versus 47.1%). Moreover, it also takes more time to achieve the requested Target Time for anticipated flights (mean of 3.5 minutes versus 14 minutes for delayed flights). This yields interesting points for further work in light of other SESAR 3 supported projects such as HARMONIC.