# Innovative Integration of Severe Weather Forecasts into an Extended Arrival Manager
## 5 Case Studies
### Synoptic Analysis
In the same day, the time until landing in the extended TMA around BGY was between 703 and 5679 s, with an average of 1332 s. There are two peaks with respect to travel time in the extended TMA between 19:30 UTC and 23:15 UTC, which are marked by the areas bounded by the dotted lines in Figure 10. The maximal and the average flown distances in the extended TMA were approximately 739 and 185 km, respectively. The average flown distance during peak time amounts to 310 km and is, through temporal closures of runways, at least 63 km greater than the corresponding average flown distance during the peak time on 7 July 2019, when BGY was not closed. Figure 11 illustrates the accumulated rainfall per ten minutes on 6 August 2019 at BGY, which correlates with the peaks for travel time shown in Figure 10. However, there are no significant peaks between 19:30 UTC and 23:15 UTC at the nearby MXP airport, as illustrated in orange in Figure 10.  
The last pair of datasets was recorded on 11 May 2019 and contains 233 arrivals to MXP and 122 arrivals to BGY. On this day, a squall line hit MXP between 14:00 UTC and 16:00 UTC causing intense precipitation and heavy hail formation [46]. These adverse weather conditions (Figure 12) led to the airport's closure for about 40 min and some flight delays. Figure 11: Histogram of the rainfall (blue bars) and accumulated rain (red line) at the Bergamo airport on 6 August 2019 [46]. Figure 10: Travel time in the extended TMA vs. touchdown time for historical traffic at MXP (orange color) and at BGY (blue color) on 6 August 2019. In addition, nine aircraft were diverted to other airports. Figure 13 illustrates travel time at the extended MXP TMA, which was between 719 and 4693 s with an average of 1196 s. This distribution indicates that controllers had to guide many aircraft into holdings. According to Figure 13, the airport was closed at around 16:00 UTC. The maximal and average flown distances in the extended TMA were approximately 676 and 165 km, respectively. The average flown distance during the peak time was equal to 349 km. Historical traffic at BGY on 11 May 2019 indicated a time until landing in the extended TMA of between 782 and 2985 s, with an average travel time of 1197 s (Figure 13). There was a peak period with respect to travel time between 17:30 UTC and 19:30 UTC, probably as a consequence of the weather conditions at MXP airport described above. The maximal and average flown distances at the BGY extended TMA were approximately 415 and 109 km, respectively, and the average flown distance during the peak period is equal to 215 km. Although the weather conditions at BGY did not cause a runway closure, one can notice the direct influence of the weather conditions at MXP on operations at BGY. Therefore, the historical dataset for MXP on 11 May 2019 was chosen to construct simulation traffic scenarios for investigation of the influence of adverse weather on arrival traffic. Table 1 summarizes the mentioned parameters for the three considered case studies. Figure 9.0 Apron of a runway at MXP on 11 May 2019 [53]. Figure 9.1 Visualization of travel time in the extended TMA and touchdown time for historical traffic at MXP (orange color) and at BGY (blue color) on 11 May 2019.