OPTIMAL Deliverable D7.4.1-2: Bremen airport ATTAS CDA flight test report

Kurzfassung

The document describes the results of the ACDA flight trials that have been carried out with DLR’s research aircraft ATTAS in Bremen. An ACDA procedure has been developed in WP2.4 for Bremen airport taking into account the idea of a late-merging point concept. This concept offers the possibility of allowing each aircraft to fly its own optimized vertical profile. Together with an RTA issues for the late merging point, this kind of concept would offer the use of such advanced procedures even in high density operations. A basic requirement for this kind of operation is the aircraft’s capability to meet the RTA. The functions developed within OPTIMAL for DLR´s Advanced Flight Management System (AFMS) allow flying an idle 4D ACDA in clean configuration until G/S intercept with an RTA given at for the late merging point or at the threshold. These functions have been tested in flight trials at Bremen airport. The focus has been on the 4D performance. In addition, SBAS guidance performance has been assessed. 23 approaches to Bremen under various weather (wind) conditions have been carried out. During some approaches, we even experienced a big difference between the wind forecast and the actual wind conditions during flight trials. These deviations have been alleviated by respective re-planning of the ACDA trajectory by the AFMS. This includes new point in time for the deployment of flaps 1. In total at G/S intercept, an average accuracy of -2.2 seconds with a Sigma of 4.5 seconds has been achieved. At 500ft height above threshold, the average value was -4.5 seconds with a Sigma of 7.9 seconds. Taking only into account the 16 approaches with a good match between wind forecast and actual wind the 4D accuracy was about ±3 seconds. Basically the trials have shown that • ACDAs can be flown by the FMS to meet RTA on G/S intercept or even on RWY threshold which is one main enabler for implementing ACDAs using Late Merging Point Concept • Inaccurate (weather) wind forecast will either effect RTA accuracy or reduce noise benefits of ACDAs (e.g. if earlier flaps settings are required)