*3.1. Diversion Route Finding*

The AMAN 4D-CARMA used in SINOPTICA first creates an individual waypoint list for the 4D trajectory calculation for each aircraft, which consists of both physical navigation points, such as Very High Frequency Omnidirectional Radios (VORs) or Distance Measurement Equipment (DME) and virtual Aeronautical Information Publications (AIPs), or Flight Management System (FMS) waypoints with all their altitudes and speed constraints. Usually, this waypoint list is based on the defined standard approach routes and transitions of the airport and the approach direction. If a conflict between a trajectory and a polygon of severe weather has been detected, the waypoints located inside the polygon are first determined. Afterwards, the points directly in front of and behind the polygon are searched for.

The points inside the polygon are deleted from the waypoint list, and the points before and after it are set as the start and end points for the diversion. For the route, points to the right and left of the weather are now calculated in the direction of flight, which would allow for a triangular diversion (for example, waypoints IP [*P*1*P*2] left or IP [*P*1*P*2] right in Figure 2). If it turns out that the waypoints in front of or behind the polygon are too close to it that an aircraft would have to fly a steep turn, these points are accordingly moved further away from the polygon along the route (from waypoint *P*<sup>1</sup> to *P*<sup>0</sup> in Figure 2).

**Figure 2.** The principle of diversion route calculation. *P*0, *P*1, and *P*<sup>2</sup> are points outside a weather polygon and represent the possible start and end points of the diversion. All waypoints on the waypoint list between them will be dismissed. Additionally, selected diversion waypoints such as *IP* [*P*1*P*2] *right* will be integrated and used for 4D trajectory generation.

The next step is to determine the route lengths that involve a right- or left-side diversion. In addition, the moving direction and speed of the severe weather is considered when choosing the diversion's direction. Subsequently, the newly determined waypoints are integrated into the current waypoint list and used for arrival sequencing and trajectory calculation.

#### *3.2. Arrival Sequencing*

For sequence planning, the shortest possible approach routes with the highest possible approach speeds are determined, as well as the longest routes with the lowest speeds. These result in an earliest and a latest landing time for each aircraft, and a target time window can thus be planned. The sequence is now determined by using the shortest possible approach times for each aircraft. If two aircraft fall below their weight class-dependent minimum separation, the succeeding aircraft is moved back in time until the minimum separation is reached on final and for touchdown. If an aircraft is shifted behind its latest possible landing time, it must be guided into a holding. This finally results in the landing times for the precise trajectory calculation.
