Developing Safety Performance Targets and Monitoring Plans  Section 4  4.3.5  Monitoring and Tracking of Changes Added to the Operating NAS  A change is considered to be part of the operating NAS only after monitoring is completed, the  safety performance target is achieved and maintained, and/or the predicted residual risk is  verified. At that point, the NAS change is monitored through existing Safety Assurance  processes to determine whether an acceptable level of safety is maintained. The NAS change  and all of the associated safety requirements become part of the operating NAS, which will  become the basis from which all future NAS changes will be measured. If a safety requirement  is altered or removed from a NAS change that was made part of the operating NAS, a new SRM  analysis must be performed.  The documentation that was developed during the SRM process is critical to Safety Assurance  functions, which often use SRM documents as inputs to assessments and evaluations. The  process for preparing, performing, and documenting the safety analysis is described in  Section 5.  4.3_SMSM_201904  Originally published April 2019  Uncontrolled copy when downloaded 60