In ATIS, there are 2 commands that are somewhat ambiguous. These are Event and Check Forum. The former tells pilots that’s there’s an “event in progress” and to “expect delays” while the latter simply says “Check Forum for Event Information”.
These commands are somewhat interchangeable but personally I think of it this way. If there’s an event going on that I’m controlling, be it FNF or a community event, I’ll go through this to determine which command I use.
First, if I’m controlling a hub airport, expect delays is something that is needed so I’ll go with “Event”. If the particular airport has special procedures however, I might still use Check Forum. For instance, Kai Tak will get very busy but the need for pilots to understand the approach is far greater than the need to understand traffic levels.
Long story short, if in doubt use Check Forum. If it’s a hub airport without special procedures, use Event in Progress.
