Care and Feeding of the Database

Managing electronic updates of navigation and airport data


Just what information is needed to fly an aircraft in the information age? It seems modernization of avionics systems continually delivers copious amounts of data to the flight crew. But how do these systems know what they know and how do they get current data? They are of course programmed to know. Airport and navigation data periodically changes which, in the past, required pilots to pay regular visits to their local pilot supply store and purchase up-to-date charts.

In 1973, National Airlines installed the Collins ANS-70 and AINS-70 Area Navigation (RNAV) systems in its DC-10 fleet marking the first commercial use of a required navigation database. Nowadays commonplace, portable GPS units have more memory and computing power than those early systems.

The criteria for the navigation database is defined by the ARINC 424 enabling industry standardization.

The means of obtaining current information has also changed drastically. Instead of a trip to the pilot store, the update now most frequently requires receiving electronic media either from a trip to the Internet or obtaining a package through the mail. Floppy discs are still employed for this process by some avionics manufacturers and more recent systems use means that will load a bit faster with fewer challenges and include CD/DVD or USB portable storage devices.

Supplied by FAA, DOT, etc.

The majority of the official flight navigation data in the United States is supplied by the Federal Aviation Administration and supplemented by various civil aviation authorities as well as the Department of Defense (DOD). Outside the United States this information comes from various sovereign states and is collected in an aeronautical information publication (AIP). Distribution to aircraft operators includes service providers such as Jeppeson. Once the distributor has the information, it will be applied to various media devices required by their customers to facilitate loading in specific avionics platforms.

The database update occurs at a 21-day cycle. The edited content is sent to the avionics manufacturer or prepared with the avionics-packing program. Data not coded by the 21st day will be contained in the database for the next date cycle. In order for the information to be in the database at this 21st day the actual cutoff is more like 28 days.

Who is responsible for loading data?

So just who can legally load navigation database revisions? In the United States the FAA considers this action to be preventative maintenance and thereby allows a properly trained and qualified pilot to accomplish the procedure. This method is not categorically implemented industrywide. In some operations, qualified maintenance technicians will install, test, and sign off the update in the appropriate maintenance record.

Pilot authorization for loading databases is found in Federal Aviation Regulation (FAR) Part 91 Appendix “A” and reads as follows: “Updating self-contained, front instrument panel-mounted air traffic control (ATC) navigational software databases (excluding those of automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)) provided no disassembly of the unit is required and pertinent instructions are provided. Prior to the unit’s intended use, an operational check must be performed in accordance with applicable sections of Part 91 of this chapter.

Types of RNAV systems

There are many different types of RNAV systems certified for instrument flight rules (IFR). The two common ones include global positioning systems (GPS) and multi-sensor flight management systems (FMS).

Most GPS operate as stand-alone RNAV systems. A modern GPS unit accurately provides the pilot with the aircraft’s present position; however, it must use an airborne navigation database to determine its direction or distance from another location unless a latitude and longitude for that location is manually entered. The database provides the GPS with position information for navigation fixes so it may perform the required calculations to determine the appropriate tracks, headings, and distances to be flown.

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