System Safety Concepts Dave Balderston Office of System Safety March 26, 2003

2 Outline Introduction References System Concepts Safety Risk Management Concepts Implementation Issues

3 References FAA Order , “Safety Risk Management” Draft System Safety Handbook especially Chapter 15, Operational Risk Management located at (Safety Risk Management)

4 Introduction System safety approach provides a comprehensive and disciplined, but flexible methodology for identifying and addressing safety concerns Use system perspective to understand complete situation Address safety concerns using system concepts Simple, common sense approach—do it all the time; a formalized approach can help do it better.

5 Basic Questions What is going on? –Design analysis or system monitoring What should we worry about? –Hazard identification How much should we worry? –Risk assessment What should we do? –Risk management

6 Definition of System Composite of people, procedures, materials, tools, equipment, facilities, and software Operating in a specific environment To perform a specific task or achieve a specific purpose, support or mission requirement –Such as the provision of crash/fire rescue services

7 Major Components of System for Landing Aircraft Airport Infrastructure Air Traffic Control Functions Aircraft and Crew Environmental Factors How do these system components need to interact to assure that aircraft land safely?

8 Safety Management Concepts Safety Goal: Avoid safety losses (death or injury) Strategy: Manage safety risk (likelihood and severity of potential losses) Implementation: Identify and control hazards (conditions that lead to increased safety risk)

9 Safety Risk Management Strategy Design Analysis/System Monitoring –What is going on? Hazard Identification –What should we worry about? Risk Assessment –How much should we worry? Risk Management –What should we do about it?

10 Safety Assurance Steps Designing in safety assurance (must be done in system development) Maintaining and strengthening safety assurance (Infrastructure support—procedures, training, maintenance, etc.) “Real Time” safety assurance (Operations)

11 Safety Order of Precedence Reduce risk through design (strongest) Incorporate safety devices Provide warning devices Develop procedures and training (weakest—the “human factors” issue)

12 Implementation Issues Understand the problem in system terms –Appropriate definition of system –Effective system monitoring (inadequate system monitoring can be a hazard) –Involvement of all key stakeholders Disciplined risk management process, even if expert judgment is the best available evidence –Hazard identification and prioritization –Risk assessment –Risk management

13 Example: Land and Hold Short Operations Risk Assessment Joint FAA/Industry Team Identified hazards, assessed risks Used expert judgment Report located at under Safety Risk Management headingwww.asy.faa.gov

14 Conclusion System Perspective Safety Risk Management Process Implementation Issues