1. Slide 1 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 ACAS / ASAS interaction IAPA Project Thierry Arino – Sofréavia, Project Manager ASAS TN – Session 3 Airborne spacing applications

2. Slide 2 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 Project overview  Context ACAS (ACAS II) is now part of the current ATM system ASAS is a promising option for the future ATM system Compatibility must be assured between current & future systems  IAPA Project EUROCONTROL ACAS Programme contribution Provide guidelines for the development of ASAS applications (in the context of ACAS / ASAS interaction) Comparative analysis (with & without ASAS) based on data-oriented methodology Structure with 3 phases Phase I (Nov 02/Oct 03): Framework & preliminary analysis Phase II (Oct 03/Oct 04): Full set of simulations Phase III (Oct 04/Jun 05): Final reports & guidelines

3. Slide 3 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 Preliminary analysis  Context Support the selection of a challenging ASAS application (from an ACAS / ASAS interaction perspective)  Method Construction of artificial encounters involving two aircraft with various performances Identification of encounter parameters influencing the ACAS alert triggering  Study limitations « Perfect » Communication, Navigation and Surveillance Aircraft proportions not representative of a given airspace Case study analysis

4. Slide 4 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 ASAS applications of interest  Challenging & mature Package I AS applications Availability of documentation & simulation data  Package I / ASPA-S&M application Merging phase In-trail phase  Package I / ASPA-C&P application Lateral overtaking Vertical crossing Lateral crossing  Possible extension of previous ASPA applications into ASEP applications (Package II)

5. Slide 5 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 ASPA-S&M, merging phase  Parameters of interest Altitude at WPT Required spacing at WPT Angle of convergence at WPT Relative initial speed between leading and trailing a/c  Potential TAs but only with required spacing close to 3 NM (unlikely for typical operations)

6. Slide 6 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 ASPA-S&M, in-trail phase  Parameters of interest Required spacing at WPT Relative initial altitude and spacing between leading and trailing a/c Length of the base turn  No ACAS alerts when on same leg with required spacing > 3 NM  No ACAS alerts when on opposite legs with base leg length > 3 NM

7. Slide 7 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 ASPA-C&P, lateral overtaking  Parameters of interest Encounter altitude Track spacing Relative speed between both a/c  No ACAS alerts with track spacing > 3 NM

8. Slide 8 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 ASPA-C&P, vertical crossing  Parameters of interest Encounter altitude HMD between both a/c Required vertical spacing between both a/c when level Relative vertical and horizontal speed between both a/c  Potential TAs and RAs (EMOTION-7 OP06 issue: Unnecessary RAs in 1000-ft level-off geometries)

9. Slide 9 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 ASPA-C&P, lateral crossing  Parameters of interest Encounter altitude Required spacing at the track crossing point Angle of convergence at the track crossing point Relative speed between both a/c  TAs very likely with required spacing < 5 NM  Potential RAs if Miss Distance Filtering (MDF) not effective

10. Slide 10 Malmö, 6-8 October 2003 – ASAS TN – Session 3: Airborne spacing applications – IAPA/WP00/035/W v2.0 Conclusion  Main outcomes for IAPA Phase I Likelihood & duration of TA: Highly geometry & altitude dependent MDF performance: Critical to prevent undesirable RAs Major influencing factors of ACAS / ASAS interaction Airborne spacing values Aircraft trajectory quality  Framework for IAPA Phase II and III Operational environment definition (ASPA-C&P, lateral crossing) Simulation framework Simplified model of the application behaviour ATM encounter model  Impact of ASAS operations on safety benefit provided by ACAS still to be investigated