When an Attribute is defined for Test Usage and a checkbox is established for Prognostics then all tests with that checkbox selected will be used for isolating prognostic detections only.
Typical Test marked for Prognostic detection and Isolation
Here the Horizon is set to 85 hours or each 5000 miles (60 miles/hour x 85 hours) for prognostic inspection.
Setting Test Usage to Prognostics in the Context Panel
Diagnostic Treatment of Prognostic Items
If Prognostic tests are included in a diagnostics they will always be diagnosed first. This is to treat them as normally replaced in a Prognostic manner rather than by failure. Components that are setup to be replaced by a prognostic algorithm can still fail before they meet the prognostic requirements but it is assumed in eXpress that these elements will normally be replaced by prognostics not by diagnosis. If a prognostic item becomes part of an ambiguity set it will still be treated as if it had not yet met the prognostic assumptions and becomes a possible failure item the same as any other itme in the ambiguity set. Note: Not meeting the Prognostic Requirement does not automatically make that item as good in common cause diagnsotics.
