FMS Databases RNAV

There are two databases in the FMCFMC —Flight Management Computer, Navigation and Performance, so firstly, do not invent any others!

When it comes to the content of these, they are largely self explanatory.

• The performance database can be thought of as an ill fated flight starting from takeoff - you take off, climb, cruise, descend, hold, have to go around and then lose an engine (abnormal flight data). The performance database contains performance information for each of these stages of flight.
• The navigation database, by contrast, contains the information for getting the aircraft from A to B: routes, waypoints, the position of holds, etc.

Two points should be made here:

1. The language is potentially ambiguous, so if it says "hold data" that is probably the performance data, whereas "hold positions" or "hold locations" will be from the navigation database.
2. Terrain data and obstruction data are not included on the navigation database. Plotting every new obstruction would be impractical and you will need to consult NOTAMNOTAM —Notice To Airmens for this information.