Definition
A collection of navigation data stored in the memory of an aircraft's avionics system (such as a GPS or FMS) containing waypoints, airways, navaids, airports, runways, and instrument procedures used to compute and display navigation guidance. The database is issued by the avionics manufacturer or a data provider, has a defined effective period (usually 28 days, the AIRAC cycle), and must be current and appropriate for the operation being conducted.
Plain English
A built-in library of navigation information stored inside the aircraft's GPS or flight management system. It holds the waypoints, airports, runways, and procedures the system needs to guide the aircraft, and it has to be kept up to date.
Context Anchor
Seen when loading or checking routes, fixes, and instrument procedures in panel-mounted navigation equipment.
Derivation
Onboard' means carried within the aircraft itself, distinguishing this stored data from charts or information referenced from outside sources. It signals that the navigation information is resident in the avionics, not looked up externally.
Why Pilots Care
It supplies the navigation system with approved, current data so the pilot does not have to enter every fix manually and can receive accurate guidance.
Intuition Check
Do not think of this as just any file saved in the airplane. In this context, an onboard database is the navigation information stored in the aircraft’s avionics and used by the equipment to build and display the route or procedure.
Example Sentence 1
Before departure, the pilot confirmed the onboard database was current and that the RNAV approach for the destination was available for loading.
Example Sentence 2
An outdated onboard database prevented the flight management system from displaying the new waypoint.