Once created, Matrixes and the accompanying analyses provide a baseline which supports continual updating of both. By simply opening the INVESTIGATION CATALYST file for the system or subsystem, the current Matrix describing the operation and the hazard analysis data are at the analyst's finger tips. File maintenance should be assigned to a key person who understands the system and the software.

Changes to the Matrix and analyses .

The need for review and updates varies with systems, organizations and risks. Examples of occasions suggesting a possible need for review and possible updates include

• changes in final design stages of a system
  
• observations of deviations during system startup
• proposed procedures changes
• surprises during system operation
• proposals to make changes to the system
• technical innovations that might enhance system
• investigations of accident/incidents during operations
• observations during change monitoring tasks
• periodic audits of system operations
• incidents in related systems
• new regulatory requirements
• changes to training content
• changes in corporate culture
• operator complaints
• insurance inspections
• natural disasters
  
  Any of the above may change system interactions or the hazard analyses.