Preliminary Hazard List (PHL). A hazard identification tool used to list all potential hazards in the overall operation. Development of a PHL typically begins with a brainstorming session among the individuals performing the safety analysis. 

Process. A set of interrelated or interacting activities that transforms inputs into outputs. 

Program Assessment. A Safety Assessment’s review of an organization’s safety programs or initiatives. Programs and initiatives include, but are not limited to, Service Area Quality Assurance, Air Traffic Facility Quality Control, Runway Incursion Prevention Plans, Equipment Availability Programs, and Contractor Quality Assurance programs for FAA contract towers. 

Qualitative Data. Subjective data that is expressed as a measure of quality; nominal data. 

Quality Assurance. A program for the systematic monitoring and evaluation of the various aspects of a project, service, or facility to ensure that standards of quality are being met. It is a process to assess and review the processes and systems that are used to provide outputs (whether services or products) and to identify risks and trends that can be used to improve these systems and processes. 

Quality Control. A process that assesses the output (whether a product or service) of a particular process or function and identifies any deficiencies or problems that need to be addressed. 

Quantitative Data. Objective data expressed as a quantity, number, or amount, allowing for a more rational analysis and substantiation of findings. 

Recording. The process of documenting the identified hazards and the associated safety analysis information. 

Redundancy. A design attribute in a system that ensures duplication or repetition of elements to provide alternative functional channels in case of failure. Redundancy allows the service to be provided by more than one path to maximize the availability of the service. 

Requirement. An essential attribute or characteristic of a system. It is a condition or capability that must be met or passed by a system to satisfy a contract, standard, specification, or other formally imposed document or need. 

Residual Risk. 

• FAA Definition. The remaining predicted severity and likelihood that exist after all selected risk control techniques have been implemented. 

• ATO Definition. The level of risk that has been verified by completing a thorough monitoring plan with achieved measurable safety performance target(s). Residual risk is the assessed severity of a hazard’s effects and the frequency of the effect’s occurrence. 

Risk. The composite of predicted severity and likelihood of the potential effect of a hazard. 

Risk Acceptance. The confirmation by the appropriate management official that he or she understands the safety risk associated with the NAS change and that he or she accepts that safety risk into the NAS. Risk acceptance requires that signatures have been obtained for the 

