alternatives are eliminated as discriminators, leaving those that differ to be of prime importance  to the CSA.  An FA, as described in the FAA SEM, is used to examine the functions and sub-functions of a  system solution that may accomplish the system’s operation or mission. An FA describes what  the system does (not how it does it) and is conducted at a level needed to support later  synthesis efforts. Products from the FA, such as the Functional Flow Block Diagram and  N 2  diagram (although other techniques may be used to diagram system functions), are further  matured as the system’s lifecycle progresses and may be used when developing the CSA. If  the alternative solutions are sufficiently diverse, then the functional architectures (as yet solution  agnostic) begin to exhibit significant differences that affect safety risk, making the CSA valuable. Should no difference in safety risk be determined, the CSA no longer helps to distinguish a  preferred alternative, which leaves outside Business Case factors as sole determinants. Note : The FA involves an iterative process that results in an increasingly refined functional  architecture. The functional architecture cannot be finalized until the system’s final  requirements are completely defined. This most likely is after the CSA is performed. A Functional Hazard Assessment (FHA) is a methodical approach to identifying credible  operational safety effects through the assessment of system or sub-system functions and failure  conditions. The FHA identifies and classifies the system functions and safety hazards  associated with functional failure or malfunctions. It identifies the relationships between  functions and hazards, thereby identifying the safety-significant functions of the system as well  as the hazards associated with that functionality. This identification provides a foundation for  the safety program to scope additional safety analyses. Describe the solutions under study in terms of the 5M Model, per the SMS Manual. At this  point, a number of different architectures and alternatives have been identified to meet the  operational requirement. Describe each alternative in sufficient detail to ensure the audience  can understand the proposed solution. As necessary, make assumptions that are conservative in nature and clearly identified. Make  them in such a manner that they fairly distinguish among the alternatives which aspects do or  do not adversely affect the safety of the solution.  Perform an FA/FHA (or expand the one previously developed) in accordance with the FAA SEM  and Safety Risk Management Guidance for System Acquisitions  Appendix C. Attempt to match  similar and unique causes associated with each hazard into a firm list of unique events that may  be adequately addressed by existing functions or by postulating new low-level system functions. This analysis results in complete sets of hierarchical functions that alternative system solutions  must perform.  Look for matches between system function and mitigation of all causes (within system bounds). Organize causes that fall beyond system bounds into assumptions and constraints for  D_SRMGSA_202003 Originally published March 2020  Uncontrolled copy when downloaded  D-4 4.2.3  Perform/Expand the FA/FHA  4.2.2  Make Assumptions Only If Specific Information Is Not Available  4.2.1  Describe the Solutions/Alternatives  4.2  CSA Development Process  4.1.4  Functional Hazard Assessment  4.1.3  FA 