Within the button that opens the form try this:-
in the ON CLICK property put-
Private Sub _<ButtonName>_Click()
On Error GoTo Err_<ButtonName>_Click
Dim strDocName As String
Dim strFilter As String
strDocName = "<FormName>"
strFilter = "([TBL Base Data].[Unit Type]="Adross"

"
DoCmd.OpenForm stDocName,, strFilter
Exit__<ButtonName>_Click:
Exit Sub
Err___<ButtonName>_Click:
MsgBox Err.Description
Resume Exit_<ButtonName>_Click
End Sub
In other words it's saying 'open the form and use the filter'