ESARR 4 - Risk Assessment and Mitigation in ATM


ESARR 4 develops further ESARR3 requirements on risk assessment and mitigation and documentation of the process, its results and conclusions.

This requirement concerns the use of a quantitative risk based-approach in ATM when introducing and/or planning changes to the ATM system. It covers the human, procedural and equipment (hardware, software) elements of the ATM system, as well as its environment of operations.

ESARR 4 covers the complete life-cycle of the ATM system, and, in particular, its constituent parts. The assessment of planned and/or implemented organisational or management changes to the ATM service provision are outside the scope of the requirement.

The objective of this requirement is to ensure that the risks associated with hazards in the airborne and ground components of the ATM system are systematically and formally identified, assessed, and managed within safety levels, which as a minimum, meet those approved by the designated safety regulatory authority.

The Hazard Identification, Risk Assessment and Mitigation Process

The hazard identification, risk assessment and mitigation process includes:

  • Determination of the scope, boundaries, functions and interfaces of the constituent part being considered, as well as its environment of operations.
  • Identification of ATM-related credible hazards, failure conditions and their combined effects.
  • Determination of the safety objectives to be placed on the constituent part.
  • Derivation of appropriate risk mitigation strategy, including development of safety requirements.
  • Verification of all identified safety objectives and safety requirements.
  • Collating and documenting the results, associated rationales and evidence to demonstrate that the constituent part under consideration, as well as the overall ATM system are, and will remain tolerably safe.

To achieve a harmonised implementation of the requirement by ATM service providers, a severity classification scheme for assessment of hazard effects and a risk classification scheme, as well as guidance for their application, are provided at Appendix A to ESARR 4. However, the risk classification scheme is incomplete due to the lack of required safety data. It is to be determined at national level based on past evidence on numbers of ATM related incidents.

Transposition into Community Law

ESARR 4 has been transposed into European Community law by Regulation 1035/2011 - Common Requirements for the Provision of Air Navigation Services which was repealed by Regulation 2017/373 in 2020.

For more detailed informaion go to article: Transposition of ESARRs into Community Law

Further Reading


Further information is available on the EUROCONTROL ESARR4 Website


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