Ron Lee wrote:

But airport identifiers change.

True. Goodrich dropped all the small airports from the Foster database around
1995. I ran with a 1993 database in my unit. Every once in a while, I would try
to use an airport as a waypoint and find that the identifier had changed. It was
annoying. In one case, I entered the new Id as a user-defined waypoint, but
that's a pain. I was never in the habit of getting frequencies from the
database, though. I always used charts or the directory for that.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.