Safety Case and Assessment

When developing or modifying air traffic control, airport, or airline operations and procedures good practice requires that these are introduced only after the safety of the designed or changed procedures has been assessed as compliant with appropriate safety criteria. In Europe, this good practice has been formalized for ATM by means of the EUROCONTROL Safety Regulatory Requirement on Risk Assessment and Mitigation in ATM (ESARR 4), which in turn has largely been included in the European Commission Regulation laying down common requirements for the provision of air navigation services (No 2096/2005).


NLR-ATSI's safety assessment methods (see Safety methods database ) and models (see Safety Modelling) can be applied to various types of air transport safety studies, for instance concerning collision risk, controlled flight into terrain and wake vortex risk. NLR-ATSI has been awarded many contracts by Air Navigation Service Providers and airports to carry out safety assessments to support the implementation of new and changed operations. Some examples are:

  • For Avinor (the Norwegian ANSP), NLR-ATSI has carried out a safety assessment of down manning staff in towers at six airports;
  • For LVNL (the Dutch ANSP), NLR-ATSI has carried out safety assessments of operations at Amsterdam Airport Schiphol, like parallel approaches and departures, converging approaches, missed approaches, crossing active runways, introduction of a new runway, building a second air traffic tower;
  • For Belgocontrol (the Belgian ANSP), NLR-ATSI carries out safety assessments for the introduction of multilateration and digital ATIS;
  • For ATNS (the ANSP of South Africa), NLR-ATSI carries out safety assessments for the introduction of RVSM in Africa;
  • For DFS (the German ANSP), NLR-ATSI has completed a study to identify the safety implications of the use of GPS in non-precision approaches, followed by a study of GPS stand-alone departure procedures;
  • Evaluations of the accuracy of GPS-based non-precision approaches and transitions were carried out under contract by the Dutch CAA and LVNL
  • Several safety assessments have been and are being performed for Skyguide (the Swiss ANSP), including a determination of collision risk related to P-RNAV transitions and approaches;
  • NLR-ATSI is supporting EUROCONTROL in several studies to establish and validate appropriate regulation for the application of RNAV in terminal airspace. Other studies focus on assisting EUROCONTROL in the development of safety arguments to support implementation of RNAV operations at European airports.
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