Fault Detection and Isolation (FD&I) outputs are the audio and visual indications, symptoms, printouts, readouts, or results of manual procedures that identify to the maintenance technician the procedure to follow in the event of an item failure. Some common types of FD&I outputs are BIT (built-in test) outputs, meter readings, alarms, display presentation, improper system operation, and system operating alerts.

A Maintainability FD&I Library file stores the tasks to perform when an FD&I output occurs. There can be zero or more Maintainability FD&I Library files in the Project. Maintainability FD&I Library files can also reside in the Common Library.

You need to create a Maintainability FD&I Library file only if you are organizing maintenance tasks by FD&I outputs. When entering maintainability data for a repairable item, you can then choose repair tasks from either enabled Maintainability Tasks or FD&I Library files.

The Maintainability FD&I Library file has two panes in which FD&I output codes and descriptions are entered and the tasks associated with these outputs are specified. The following table describes these panes: