1. 1 Acceptable Levels of Safety Severity Classification Likelihood Classification Risk Classification Scheme Safety Objective Classification Scheme Regulations / Safety Management Manual

2. 2 Acceptable Levels of Safety

3. 3 Define which indicators are to be used to define Acceptable Levels of Safety Severity Classification Scheme Effect on safe operations of aircrafts and occupants Effect on the ability to provide safe Air Traffic Management services Define what is acceptable Qualitative (no precise measure) Quantitative (precise measure)

4. 4 Acceptable Levels of Safety Severity Classification Scheme (effect on aircraft / occupants) SeverityDefinition Accident ICAO Annex 13: An occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight until such time as such persons have disembarked, in which: - A person is fatally or seriously injured (as a result of..) - The aircraft sustains damage or structural failure (which..) - The aircraft is missing or is completely inaccessible Serious Incident ICAO Annex 13: An incident involving circumstances indicating that an accident nearly occurred. Major Incident An incident associated with the operation of an aircraft, in which safety of aircraft may have been compromised, having led to a near collision between aircraft, with ground or obstacles (i.e., safety margins not respected which is not the result of an ATC instruction). Significant Incident An incident involving circumstances indicating that an accident, a serious or major incident could have occurred, if the risk had not been managed within safety margins, or if another aircraft had been in the vicinity. No safety effect An incident which has no safety significance. Not determined Insufficient information was available to determine the risk involved or inconclusive or conflicting evidence precluded such determination.

5. 5 Acceptable Levels of Safety Severity Classification Scheme (effect on ability to provide ATS) SeverityDefinition Total inability An occurrence associated with the total inability to provide any degree of ATM Services in compliance with applicable Regulatory Requirements, where: - There is a sudden and non managed total loss of ATM service or situation awareness - There is a totally corrupted ATM service or corrupted information provided to ATS personnel. Serious inability An occurrence associated with almost a total and sudden inability to provide any degree of ATM Services in compliance with applicable Regulatory Requirements. It involves circumstances indicating that the ability to provide ATM services is severely compromised and has the potential to impact many aircraft safe operations over a significant period of time. Partial inability An occurrence associated with the sudden and partial inability to provide ATM Services in compliance with applicable Regulatory Requirements. Safe, but degraded ATM services An occurrence involving circumstances indicating that a total, serious or partial inability to provide safe and non degraded ATM Services could have occurred, if the risk had not been managed/controlled by ATS personnel within Regulatory Requirements, even if this implied limitations in the provision of ATM Services. No safety effect Occurrences which have no effect on the ability to provide safe and non degraded ATM Services. Not determined Insufficient information was available to determine the risk involved or inconclusive or conflicting evidence precluded such determination.

6. 6 Acceptable Levels of Safety Likelihood Classification SeverityQualitative definitionQuantitative definition Extremely rare Has never occurred yet throughout the total lifetime of the system. 1,55 * 10 -8 per Flight hours (equal to 2,31 10 -8 per Flight) Rare Only very few similar incidents on record when considering a large traffic volume or no records on a small traffic volume. 1 * 10 -7 per Flight hours Occasional Several similar occurrences on record – Has occurred more than once at the same location. 1 * 10 -6 per Flight hours Frequent A significant number of similar occurrences already on record - Has occurred a significant number of times at the same location. 1 * 10 -5 per Flight hours Very frequent A very high number of similar occurrences already on record- Has occurred a very high number of times at the same location. 1 * 10 -3 per Flight hours

7. 7 Acceptable Levels of Safety National Risk Classification Scheme LikelihoodSeverity LikelihoodQualitative definition Quantitative definition AccidentSerious Incident Major Incident Significant Incident No safety effect Extremely rare never occurred 1,55 * 10 -8 per Flight hours Rare few similar incidents Occasional Several similar occurrences Frequent significant number occurrences Very frequent high number of occurrences

8. 8 Acceptable Levels of Safety National Risk Classification Scheme LikelihoodSeverity LikelihoodQualitative definition Quantitative definition AccidentSerious Incident Major Incident Significant Incident No safety effect Very frequent high number of occurrences AAAA Frequent significant number occurrences AAA Occasional Several similar occurrences AA Rare few similar incidents A Extremely rare never occurred 1,55 * 10 -8 per Flight hours

9. 9 Acceptable Levels of Safety National Risk Classification Scheme LikelihoodSeverity LikelihoodQualitative definition Quantitative definition AccidentSerious Incident Major Incident Significant Incident No safety effect Very frequent high number of occurrences AAAAD Frequent significant number occurrences AAAD Occasional Several similar occurrences AAD Rare few similar incidents ADD Extremely rare never occurred 1,55 * 10 -8 per Flight hours DDD

10. 10 Acceptable Levels of Safety As low as reasonable practicable The risk is less than the pre-determined unacceptable limit, and the risk has been reduced to a level which is as low as reasonable practicable (ALARP) and the benefits of the proposed system or changes are sufficient to justify accepting the risk In determining what is reasonably practicable in this context, consideration should be given to both the technical feasibility of further reducing the risk, and the cost. All such cases should be evaluated individually. Showing that the risk in a system is ALARP means that any further risk reduction is either impracticable or grossly out-weighted by the costs.

11. 11 Acceptable Levels of Safety National Risk Classification Scheme LikelihoodSeverity LikelihoodQualitative definition Quantitative definition AccidentSerious Incident Major Incident Significant Incident No safety effect Very frequent high number of occurrences AAAAD Frequent significant number occurrences AAABD Occasional Several similar occurrences AABCD Rare few similar incidents ABCDD Extremely rare never occurred 1,55 * 10 -8 per Flight hours BCDDD

12. 12 Safety Regulatory Framework Legal Framework Air Navigation Orders Safety Management Manual ICAO Annexes 11, 14 Safety Occurrence Reporting Acceptable Levels of Safety Management Procedures Risk Classification Scheme Acceptable Levels of Safety Risk Classification Scheme

13. 13 ATM Contribution Factors METNAV/EnrNAV/Ter m GroundTWRAPPACC Safety factor for Accidents (1,55 10 -8 per Flight hour) Mid-air collision ÷ Controlled flight into terrain ÷ Accident on ground with fatalities ÷ ÷÷ …… Safety Factors for Serious Incidents Separation minima infringement (less than 50%) ÷ Runway incursion with avoiding action ÷ ÷÷ ……

14. 14 Target Levels of Safety

15. 15 Safety Regulatory Framework Legal Framework Air Navigation Orders Safety Management Manual ICAO Annexes 11, 14 Safety Occurrence Reporting Acceptable Levels of Safety Management Procedures Risk Classification Scheme Acceptable Levels of Safety Risk Classification Scheme Apportioning Safety Targets