So why is it so cumbersome and difficult?
Maybe because each of the analysis methods applied requires its own arithmetic and often also its own tool. On top often the systems under consideration are multidiciplinary and complex. That means you will need to meet experts from the various fields, understand their language, their drawings, their mindset. And often it turns out, that there was more in the mindset than in the system documents. Undocumented features, so to say. But talking about system safety, this could result in serious side-effects once the system is in operation.
The problem is the expressitivity in the formats and tools used for documentation: Text-documents, spreadsheets and even graphical drawings lack depth of clearly capturing and showing the system behavior. Often this results in more time spent for clarifying document lacks and version issues than for creative engineering work.
The Idea