This chart demonstrates that different navigation styles are adequate to the four interaction modes:

• Direct access implies that all the control features that may be required for executing a task are available to the operator, and are visible (on an operational panel or on screen). The search for the feature is visual; the operator need only to scans the screen displays. No interaction is required for accessing the feature. It is best suited for Routine operation.
• The access to features when operating in unfamiliar situations should be mostly guided.
• In troubleshooting (under hazard) the operators might need search facilities to solve problems unforeseen at design time.

Updated on 07 May 2016.