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## 4.2.8 Assess Development Assurance Risk 

Consider the architectures of the alternatives, the different components, and their DALs. Developing all components to the highest DAL is expensive and spreads all the developer’s resources across the entire project. However, partitioning the components may permit different DALs, limiting the most severe functions to one component. Other functions can be assigned lower DALs, thus conserving resources. Also, if the different implementations are from different vendors, consider their experience with the DAL standard; inexperience may add additional risk. 

## 4.2.9 Establish Safety Requirements and Predict Residual Risks 

For each alternative, establish: 

• Preliminary safety issues for tracking in the future; 

• Needs, which may become requirements when validated; 

• Missing functional requirements needed to turn solution fragment(s) into complete and viable solutions; and 

• Predicted residual risk levels based on potential and achievable performance minima should this alternative be selected, designed, fabricated, tested, fielded, and logistically supported for its full lifecycle. 

At this point, the CSA may only lay the groundwork to better define a preferred alternative (as yet unselected) that will be better detailed in the PHA. Again, some aspects of relative difference among alternatives may be apparent even if absolute measures of each alternative’s suitability against the reference case may not be known. 

Intelligently discount and drop out similar unknowns deemed “equal” across each of the alternatives, leaving the known differences as key points of distinction. When completed, the CSA positively impacts the decision-making process by helping to discount several lesser alternatives, indicating one preferred alternative on the basis of clear differences in predicted residual risk. Alternatively, the CSA may return a “no discernible difference” result, leaving subsequent IIDs to be made on the basis of outside business case factors. Use Table D.3 to tabulate results. ( Note : Each alternative assessed has its own table.) 

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## 4.2.10 Make Recommendations Based on the Data in the CSA 

For decision-making purposes, compare the results of the safety risk assessment of each alternative considered. Compile the results in Table D.4. ( Note : Not all hazards may apply to each alternative assessed. Enter “N/A” in Table D.4 when appropriate.) Ensure the decision 

