Left([WhateverTheFieldIsCalled], 3)

If you want to do this permanently, you'd use an Update query. If you only
need to be able to display it, you can simply use that in a query as a
calculated field.

--
Doug Steele, Microsoft Access MVP
http://I.Am/DougSteele
(No private e-mails, please)

Yes, you can do it though an update query. Start a new query in design view,
select the table and get the field down to the grid; I'll assume the field
to be called fldAirport for the purpose of this example, and you'll change
accordingly.
Go to menu item Query > Update; notice the new line headed Update to that
appears in the grid; in this line, under the field fldAirport, type in:
Left([fldAirport],3)
(remember to use the actual field name). Run the query through the menu
(Query > Run), confirm that you want the changes made to the records, and
you're done.

As a general rule, whenever you're trying something new, or of which you are
not 100% sure, make a back-up copy of your .mdb before you try it!

HTH,
Nikos

Thanks for the help.  Works great