En Route

What is a published RNAV (Q) route, and who can use it?
What is an “unpublished” RNAV route, and when can you fly it?
What is the Magnetic Reference Bearing (MRB), and what are the limitations on its use?

What requirements must your GPS meet before you can use it for IFR—e.g., equipment and installation approvals, operation in accordance with approved AFM or flight manual supplement, etc.
Under what conditions can you use GPS in place of other equipment?
Under what circumstances must you have (and use) a means of navigation other than GPS?
What is RAIM, and when is it required?
What are GPS NOTAMs and how do you find them?
Must your database be current?
How and where are GPS database updates logged?
How does course and distance information on a GPS navigation display differ from data presented on navigational charts and conventional instrumentation?