HRA: Aerospace Challenges Including Human Reliability In Considerations for Risk Diana DeMott – SAIC diana.l.demott@nasa.gov 281.335.2056

What is HRA? Human Reliability Assessment (HRA) The human in the loop directly causes a failure or accident The human does something to make a failure worse The human fails to correct the problem

Types of Human Actions (that can contribute to failures) Direct actions (push the button, switch) Monitor (verify information or programmed activities) Support (provide information which influences direct action) Evaluate (cognitive process to determine the course of action to be taken) Errors of omission versus commission Test and maintenance errors Procedural errors (not following or skipping steps) Errors leading to inappropriate actions Recovery errors

Why Use HRA? Identify how human actions (or inactions) affect accidents or failures Identify human-in-the-loop contribution to reduce the risk Complete the risk picture Performed during the design phase, HRA can highlight human interfaces and postulated failures and influence design (Risk Informed Decision Making) Determine if the risk can be mitigated by modifying the design Feedback to system design, Human Factor Engineers, operations procedures, and simulator training scenario development Design redundancy issues could use the HRA assessments for cost / benefit trade studies Comparison of competing designs Prioritization of design considerations

HRA Challenges Individual Human Action Being Assessed End User of HRA Results Perception Accused of not performing job properly Machines are more reliable than people Results What actions are most important based on risk Where to concentrate efforts for reducing risk Understanding What can be done to eliminate or mitigate human errors People are part of any process with advantages and disadvantages Results Understanding

Examples of Human Reliability Pilot preparing for take-off – actions important for the safety of all Passengers – actions important for individual safety

Conclusion HRA is another tool that can be used to improve designs and/or operations to reduce overall risk and provide information for Risk Informed Decision Making When using a tool: Know what the tool can do for you Use the right tool for the job Know how to use the tool effectively