## 3.4 Use of Results 

The results of the OSA are used as input to various documents. 

## 3.4.1 Preliminary Requirements 

Controls and safety requirements identified through the OSA process must be included in the preliminary Program Requirements Document (pPRD). The pPRD must include a requirement for DALs in accordance with Appendix J. Other preliminary requirements must be separately documented, such as new/modified Air Traffic Control (ATC) procedures, changes to the Codes of Federal Regulation, and training. 

## 3.4.2 Safety Risk Management Documents 

The output of the OSA is used as input for Safety Risk Management (SRM) documents that the PO must develop as the solution is further developed (e.g., Comparative Safety Assessment, Preliminary Hazard Analysis, or System Hazard Analysis / Sub-System Hazard Analysis). 

## 3.4.3 Safety Requirements Verification Table 

The Safety Requirements Verification Table contains all of the safety requirements identified, starting with the origin of the requirement (including those identified in the OSA). 

## 4 OSA Inputs 

## 4.1 FHA 

An FHA is not a required AMS safety analysis; but if one is conducted, it can be useful input for the OSA (particularly when complex systems are being developed). 

## 4.1.1 What is an FHA? 

The PO may conduct an FHA to identify credible operational safety effects through the analysis of system or sub-system functions and failure conditions. The FHA is a methodical approach that identifies and classifies the system functions and safety hazards associated with functional failure or malfunction. 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. 

## 4.1.2 Purpose of an FHA 

The purpose of an FHA is to identify every expected function of a system and consider the hazards that may result when each function fails in every possible way. It does not determine causes of the hazards but rather focuses on the consequences and corresponding severities. As a predictive technique, the FHA attempts to explore the effects of functional failures of parts of a system. A guiding principle of the FHA is that if safety requirements are added at the functional level early in the system development process, the design of the system will be more stable from a safety perspective, and the cost of implementing safety mitigations will be reduced. 

## 4.1.3 FHA Overview 

The FHA is an engineering-oriented analysis. To conduct an FHA, the PO must convene a technical or engineering-oriented workgroup before any SRM panel is held to review the Functional Analysis (FA), pPRD (if available), Enterprise Architecture (EA) artifacts, and other inputs. To assist the safety program by defining functions and identifying likely functional hazards, the FHA facilitates discussion of mitigations and solutions. The FHA assists any stakeholders participating in subsequent SRM panels (e.g., to conduct OSAs) who may not 

