Simulations investigating combined effect of lateral and vertical navigation errors on PBN to xLS transition

Building further on previous PBN to precision final approach transition work (PBN to xLS), EUROCONTROL in collaboration with the Technical University of Berlin (TUB) and under the SESAR1 work programme, conducted an experiment investigating the combined lateral and vertical performance of 5 different aircraft types when transitioning from a curved PBN procedure to a precision final approach procedure (using an ILS, GLS or more generically an xLS landing system). While earlier work has concentrated primarily on either lateral or vertical performance during these operations, the current work focusses on the combined lateral and vertical transition aspects. Arinc 424 procedures, consisting of a 180 degree turn using the Radius-To-Fix path terminator, connected to either a 3NM or a 6NM Final Approach Segment were implemented in 5 different aircraft simulators of the following types: A340, B777, B737, E190 and Dash8Q400. To test the procedures under the most realistic conditions, simulated lateral navigation errors ranging between -0.15NM and 0.15NM were introduced in the PBN segments of each procedure, while non-standard temperatures ranging between ISA-37 and ISA+35 were implemented in the simulator. Besides the effect of the lateral navigation errors on the xLS transition already studied in the previous work, the additional effects of deviations in the vertical profile caused by the non-standard temperatures were investigated. Also, a number of scenarios were added to the test cases which contained steeper glide paths with angles up to 4 degrees. Conclusions were formulated regarding the different aircraft capabilities and performances, as well as flight crew considerations. The overall conclusion of this work is that it is possible for all investigated aircraft to transition directly from a curved PBN procedure to an xLS procedure without the requirement of an intermediate segment between final approach course and glide path interception. This is true under the conditions that the glide path is intercepted at a certain distance from the threshold and from a PBN segment containing a defined vertical path which is significantly shallower than the glide path. Additionally, final approach course and glide path capture will require flight crew interventions other than just arming the approach mode in certain situations, i.e. high above ISA temperature deviations and lateral navigation errors. The final objective of this work is to progress to set of procedure design criteria which would enable the design and publication of PBN to xLS procedures.