June 26, 1992
                                      ADD_NAV
                     ROUTENAV Airport Database Update Utility 



INTRODUCTION

      ADD_NAV is a utility program to update your current ROUTENAV
      airport database without deleting the changes you have made to
      the database.


OPERATION

      ADD_NAV can be used from within ROUTENAV or from the DOS
      command line.  To use ADD_NAV from within ROUTENAV, the
      program must be in the same directory as ROUTENAV.EXE.

      To start the program, type ADD_NAV from DOS or select OPTIONS,
      ADD_NAV from the ROUTENAV main menu screen.

      Enter the complete path of your current database.  If your
      current database is in the current directory, you can leave
      this entry blank.

      Enter the complete path of the database you wish to use to
      update your current database.

      Selecting ABORT will put you back in DOS.  Select CONTINUE to
      procede with the update procedure.

      When you select CONTINUE, the program firsts compares the full
      date and time stamp of each *.IDX file to determine which
      files are different.  The logic here is, if the current
      database file (A.IDX for example) has the exact same date and
      time (down to the second) as the new database file, then the
      files are the same and don't need to checked.

      Once the program has determined which files need to be
      updated, it compares each one of these files in alphabetical
      order.  The program compares each airport in the new database
      to the airports in the current database (Again, only the files
      that are different will be checked).

      ADD_NAV first checks to see if the airport exists in the
      current database, by checking for the ID and State.  If it
      does not find the ID and State in the current database, it
      adds the airport to the appropriate file.

      If ID and State do match an airport in the current datatase,
      the program checks to see if the airports in the new
      database and the current database are identical.  If so, then
      it moves on to the next airport in the new database.If the two airports are not identical, then you are shown a
      side by side comparison of the two databases.  It is your
      decision to update you current database, or leave it as it is.

      While viewing the side by side display of the airports, you
      can compare the frequencies or runways by selecting their
      respective buttons.  While viewing the frequencies or runways,
      pressing the ENTER or ESC keys, or selecting the close button
      in the upper left corner of the screen will return you to the
      COMPARE screen.

      I hope this utility helps you to accumulate a fairly
      significant database.  If you are are willing to send me (or
      upload to me) your updated database, I will be happy to return
      the favor.  If everybody helps out, we should have a very
      complete database (both U.S> and Canada) in no time.


                                                                      Tom Arduini