The Safety Analysis and Risk Mitigation Process  Section 3  3 3  3.4_SMSM_201904  Originally published April 2019  Uncontrolled copy when downloaded coordinate with the ATO Chief Safety Engineer to address the risk and any potential corrective  actions.  Refer to  Section 3.7.2 for risk management strategies. Refer to Section 5.5.3 for information on  the administrative process of addressing existing high-risk hazards and obtaining approval for  their risk reduction.  When considering new NAS equipment and procedures or planned modifications to current  NAS equipment and procedures, define the data sources and measures necessary to identify  hazards. The elements of a thorough system description contain the potential sources of  hazards associated with the proposed NAS change. There are numerous ways to do this, but  all require at least three elements:  In many cases, to identify and analyze safety hazards, a Preliminary Hazard List (PHL) and the  required Hazard Analysis Worksheet (HAW) will suffice. Some cases, however, may require  other tools or techniques (refer to Section 3.4.3.1.3).  The process of describing the system using a tool like the 5M Model is designed to facilitate  brainstorming for sources of hazards. The next step in the hazard identification process is to  develop a PHL. The  PHL  may be a combination of hazards, causes, effects, and system states. The items listed in the PHL all have the potential to be placed into the HAW. It is at the panel’s  discretion to decide which items belong in the HAW during the Identify Hazards and Analyze  Risk phases of the SRM process. For more guidance on which items should be placed into the  HAW, refer to Section 3.5. When hazards are identified, the  HAW , a worksheet used to document a safety analysis, is  required as part of the ATO SRM process. It is also used both for Operations and Second-Level  Engineering. When developing the HAW, it is crucial to consider the hazards inherent to all  aspects of an operation without regard to risk. ATO safety professionals use the HAW in nearly  all risk management applications, except in the most time-critical situations. Using the HAW helps panels overcome the tendency to focus on safety risk in one aspect of an  operation and overlook more serious issues elsewhere in the operation. Its broad scope guides  the identification of issues that may require analysis with more detailed hazard identification  tools. Refer to Section 5.4.1 and Section 5.4.4.6 for a description of the expected contents of  the HAW. If the safety analysis calls for an additional means to identify hazards and compare solutions,  select the methodology that is most appropriate for the type of system being evaluated. The  Service Center and/or an AJI safety case lead can provide additional guidance on which tool(s)  to use for various types of NAS changes (refer to Table 3.1).  3.4.3.1.3 Other Accepted Tools and Techniques 3.4.3.1.2 Developing a HAW  3.4.3.1.1 Developing a PHL  3.4.3.1 Techniques for Hazard Identification and Analysis  3.4.3  Elements of Hazard Identification • Operational expertise that relates specifically to the operation or equipment, • A defined hazard analysis tool. Training or experience in various hazard analysis techniques, and