the data storage required in their avionics by limiting the  geographic area the database covers. Like paper charts, the  amount of data that needs to be carried with the aircraft is  directly related to the size of the coverage area. Depending  on the data storage that is available, this means that the  larger the required coverage area, the less detailed the  database can be.  Again, due to the wide range of possible storage capacities,  and the number of different manufacturers and product  lines, the manufacturer’s documentation is the pilot’s best  source of information regarding limitations caused by  storage capacity of RNAV avionics.  to appear on both VFR and IFR charts and in airborne  navigation databases; and their instrument approach  procedures, if any, continue to be included – and still  appear to be valid – in the paper and electronic versions  of the United States Terminal Procedures Publication (TPP)  charts. Airpark South, 2K2, at Ozark, Missouri, is a case in  point.  Even though this airport has been closed going on two  years and, due to industrial and residential development  surrounding it, likely will never be reopened, the airport  is nonetheless still charted in a way that could easily lead  a pilot to believe that it is still open and operating. Even  the current U.S. Low Altitude En route chart displays a  blue symbol for this airport, indicating that it still has  a Department of Defense (DOD) approved instrument  approach procedure available for use.  It is important for pilots to remember that many  inconsistencies may exist between aeronautical charts  and airborne navigation databases. Since there are so  many sources of information included in the production  of these materials, and the data is manipulated by several  different organizations before it is eventually displayed  on RNAV equipment, the possibility is high that there will  be noticeable differences between the charts and the  databases. Because of this, pilots must be familiar with the  capabilities of the database and have updated aeronautical  charts while flying to ensure the proper course is being  flown.  Obvious differences exist between the names of procedures  shown on charts and those that appear on the displays of  many RNAV systems. Most of these differences can be  accounted for simply by the way the avionics manufacturers  elect to display the information to the pilot. It is the avionics  manufacturer that creates the interface between the pilot  and the database. For example, the VOR 12R approach in  San Jose, California, might be displayed several different  ways depending on how the manufacturer designs the  pilot interface. Some systems display procedure names  exactly as they are charted, but many do not.  Aircrews need to use caution when selecting an airport  in a cautionary or emergency situation, especially if the  airport was not previously analyzed suitable for diversion  during preflight. Aircrews could assume, based on charts  and their FMS database, the airport is suitable and perhaps  the only available diversionary or emergency option. The  airport however, could be closed and hazardous even for  emergency use. In these situations, Air Traffic Control may  be queried for the airport’s status.  As the data in a worldwide database grows, the required  data storage space increases. Over the years that panel-  mounted GPS and FMSs have developed, the size of the  commercially available airborne navigation databases has  grown exponentially.  Some manufacturer’s systems have kept up with this  growth and some have not. Many of the limitations of  older RNAV systems are a direct result of limited data  storage capacity. For this reason, avionics manufacturers  must make decisions regarding which types of procedures  will be included with their system. For instance, older GPS  units rarely include all of the waypoints that are coded into  master databases. Even some modern FMS equipment,  which typically have much larger storage capacity, do not  include all of the data that is available from the database  producers. The manufacturers often choose not to include  certain types of data that they think is of low importance  to the usability of the unit. For example, manufacturers  of FMS used in large airplanes may elect not to include  airports where the longest runway is less than 3,000 feet  or to include all the procedures for an airport.  The naming of multiple approaches of the same type to the  same runway is also changing. Multiple approaches with  the same guidance will be annotated with an alphabetical  suffix beginning at the end of the alphabet and working  backwards for subsequent procedures (e.g., ILS Z RWY  28, ILS Y RWY 28, etc.). The existing annotations, such as  ILS 2 RWY 28 or Silver ILS RWY 28, will be phased out and  replaced with the new designation.  NAVAIDs are also subject to naming discrepancies as well.  This problem is complicated by the fact that multiple  NAVAIDs can be designated with the same identifier. VOR  6-15  Manufacturers of RNAV equipment can reduce the size of  Charting/Database Inconsistencies  Naming Conventions  Storage Limitations 