Sometimes the transition from one situation to another situation needs additional properties which cannot be captured by a simple association. The common solution for that is to use an association class to express causality allowing for additional properties to be added to the transition. This pattern is already used in the STPA method. The proposal is to create a general pattern so other methods can access this capability. This would include creating an association class on the common core Situation.

In Enterprise Architect 15.2 the CoreRAAML.xmi is not loaded completely. The generalization relation from Situation to SysML Block is not loaded. It seems to me that the xmi export has tool-specific content.

RAAML claims to implement STPA, but some important elements are missing.

For example,

In Step-1 of the STPA process (in the 2018 Leveson/Thomas STPA Handbook – Figure 2.3) it calls out the need to derive “Safety Constraints” from the Losses. I can find no reference to Safety Constraints in the RAAML.

Furthermore the RAAML does not provide any linkage from Losses to Hazards, which is expected in the Handbook.