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To set out the common European risk classification scheme (ERCS) for the determination of the safety risk of an occurrence.
The ERCS addresses the safety risk of an occurrence and not its actual outcome. The assessment must determine the worst likely accident outcome that the occurrence might have led to, and how close to that outcome it was.
The ERCS is based on a matrix composed of two variables:
The identification of the severity of the potential accident outcome is a two step process:
The key risk areas are:
The potential loss of life is categorised by the number of possible fatalities (both in the air and on the ground):
The severity score combines the risk area and the potential loss of life and is given as a single letter:
The Annex to the Regulation contains a table which combines the key risk areas, the potential loss of life categories and the severity score.
The probability of the worst likely accident outcome is obtained by using the ERCS barrier model. It assesses the effectiveness of the safety barriers which were remaining between the actual occurrence and the worst likely outcome. Ultimately, this model determines how close the occurrence has been to the potential accident.
The model consists of 8 barriers and each of them is assigned a weight:
The effectiveness of each barrier is classified as:
The weights of all barriers scored as stopped, remaining known and remaining assumed are summed. The result (a number between 0 and 18) is converted into a barrier score between 0 and 9 (9 meaning a score of 17-18, 8 - a score of 15-16, etc.).
The safety risk score is a two-digit value where the first digit is the severity score (A to X) and the second one is the barrier score (0 to 9). This code is then put into the ERCS matrix which is a table with barrier score on one axis and severity score on the other. The cells of the table are coloured to facilitate the determination of the urgency of the recommended action to be taken about the occurrence:
Furthermore, each ERCS score is assigned a corresponding numerical value of risk magnitude to facilitate the aggregation and numerical analysis of multiple occurrences. These range between 0,000001 for an E9 occurrence (a risk of injury mitigated by a lot of barriers) and 1000000 for X0 (a catastrophic event with no barriers). The full spectrum is specified in the Annex to the Regulation.
The Regulation entered into force in December 2020 and is applicable from 1st January 2021.
Regulation 2020/2034 supplementing Regulation 376/2014 as regards risk classification scheme (OJ, 11.12.2020)
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