ASAS TN 2nd Workshop 6-8 October ADS-B Safety Analysis (ASA & GSA) Bob Darby EUROCONTROL ADS Programme ASAS Thematic Network Second Workshop 6-8 October 2003

ASAS TN 2nd Workshop 6-8 October OUTLINE  Background  Current work  analysis processes  comments on the methods, not the results  Wider context & Conclusions  Safety is only part of SPR / IA  Requirements Focus Group  Longer term  Points of Contact

ASAS TN 2nd Workshop 6-8 October BACKGROUND

ASAS TN 2nd Workshop 6-8 October Safety Work History  : Stage 0  Initial Safety Study - brief look high level workshops  : Stage 1  Operational Hazard Analysis (OHA) based on “Case Studies”  Difficulty - not detailed enough definition of the applications

ASAS TN 2nd Workshop 6-8 October Safety Work History  2002:  Package I proposed at Rome  CARE-ASAS / EUROCONTROL development of Package I  EUROCAE WG51 & RTCA SC-186  Common applications review & proposal  Common methodology proposal - ED78A / DO-264  Guidelines for Approval of the Provision and Use of Air Traffic Services supported by Data Communications  In parallel:  Stage 2A Safety Contract launched  At the time (Jan 2002) the aim was to  Use EUROCONTROL Safety Assessment Methods (SAM)  Use ED78A as a means of compliance with the SAM  Aim has changed as ESARR4 developed and use of ED78A has proceeded, to establish an effective methodology. Differences/complementarity handled as an outcome.

ASAS TN 2nd Workshop 6-8 October CURRENT WORK

ASAS TN 2nd Workshop 6-8 October Stage 2A Safety Contract  Coordinated with CBA and Architecture work  Assessment of some ADS-enabled ASA and GSA applications defined in the Package I OSED - including ADS-B in a mixed surveillance environment  For each Package I application  OHA: building on the results of the ADS Programme Stage 1 OHA  ASOR: allocation to elements / domains within the architecture  from ASOR options: safety requirements for the ADS-B element based on the specific enabling infrastructure.  PSSA for one application, using a specific architecture  Issues:  Methodology and Software tools equally important as the results

ASAS TN 2nd Workshop 6-8 October Logical Flow Case StudiesOHA STAGE 1 (Draft) OSEDs OHA Functional Architecture ASOR Specific Implementation PSSA STAGE 2A ASFA Ground Surveillance Architecture Methods & Tools inc database Assessments - architecture guidance RESULTS CBA

ASAS TN 2nd Workshop 6-8 October Applications assessed Ground Surveillance Applications (GSA) ATC surveillance in en-route airspace ATC surveillance in terminal areas ATC Surveillance in non-radar area Airport Surface Surveillance Surface Traffic Awareness application Runway Incursion application Airborne Surveillance Applications (ASA) Enhanced traffic situational awareness on the airport surface Surface Traffic Awareness application Runway Incursion application Enhanced successive visual approaches Sequencing and merging applications

ASAS TN 2nd Workshop 6-8 October OHA process

ASAS TN 2nd Workshop 6-8 October OHA output (example) From “Enhanced Successive Visual Approach” OHA is summarised in a diagram. Details in several tables: OH summary table, that refers to Candidate safety requirements lists environmental procedural technical Recommendations list Causes list Supported by detailed OH tables

ASAS TN 2nd Workshop 6-8 October OHA - comments on process  Exhaustive & detailed...  … time-consuming to develop and to review  Mature process, used (with slight variations) by many European projects, NUP, MFF, …  Needs tool support to ensure  consistency between diagrams and tables  traceability and accurate cross-referencing between all tables  database is being developed  Derived from application model in OSED  Changes to OSED may mean complete rework of OHA

ASAS TN 2nd Workshop 6-8 October ASOR process  Follows on from OHA  traceability essential  Objective: identify  responsible domains/elements (ATC, aircraft, crew,…)  system failure relationships  mitigation means strategy  Key processes:  Building the fault tree  stop when the safety requirement can be exclusively met in a domain  Allocation of safety requirements  several options

ASAS TN 2nd Workshop 6-8 October ASOR - comments on process  Relatively new process - learning as we proceed  More complex for surveillance than for communications  No single correct answer - tradeoffs will occur  Trees give the understanding - tables give the detail  Tools for traceability and consistency essential

ASAS TN 2nd Workshop 6-8 October PSSA  Specific to a particular implementation  Assess if the proposed architecture is safe for its intended purpose  ASOR has already mapped safety requirements to the domain  Now look at the architecture within the domain: i.e. main functional (and physical) components  EUROCONTROL study example: Toulouse airport  Package I applications:  Airport Surface Surveillance  Enhanced traffic situational awareness on the airport surface  Surface Traffic Awareness application  Runway Incursion application  Just starting this phase of the study

ASAS TN 2nd Workshop 6-8 October Overall Comments  Learning about the processes as we use them going from the generic to the specific  Status  OHA: mature but effort intensive  ASOR: developing well  PSSA: just started but relatively straightforward  Overall: large effort  Tool support essential, especially when iterating and reworking  Complementary approach to identify critical areas would pay dividends  OSED is critical - clarity and accuracy of application modelling is vital

ASAS TN 2nd Workshop 6-8 October WIDER CONTEXT & CONCLUSIONS

ASAS TN 2nd Workshop 6-8 October Safety is only part of the process OSED Operational Service & Environment Definition OSA Operational Safety Assessment OHA & ASOR OPA Operational Performance Assessment Identify & allocate performance requirements IA Interoperability Assessment SPR Safety & Performance Requirements Interop Document

ASAS TN 2nd Workshop 6-8 October Preparation for RFG/3  Joint EUROCONTROL, FAA, EUROCAE, RTCA “Requirements Focus Group”  1st-4th December 2003, Washington DC  OSEDs: OSED Harmonisation Group  First complete PI OSED due out soon  Safety: EUROCONTROL, NUP, MFF, …  Convergence on the methods  More coordination and consensus needed - EC can help?  SPR & IA as a whole  ad-hoc SPR/IA group working since July  aiming at common approach for Europe and USA; extend world-wide?

ASAS TN 2nd Workshop 6-8 October Longer term considerations  Operational expertise to validate the analysis conclusions  Complementary methods could be of value  for greater efficiency overall  for confirming results  Coordination with Safety Unit, SRC and EASA

ASAS TN 2nd Workshop 6-8 October POINTS OF CONTACT  EUROCONTROL ADS Programme  visit the ADS Programme website :   STNA & Sofréavia  who have carried out the detailed work and developed in a practical form the processes described today  RFG colleagues  discussions in preparation of material for RFG/3