Snowbird wrote:



Fact: many IAFs are not in ATC computer databases outside the local
ATC facility.

The vast majority aren't.



Fact: filing a flight plan to a fix not in the computer database of
the originating facility will cause the computer to stop processing
the flight plan.

No it won't. AFSS can put in a flight plan that I can't. They can put
in a plan with regular airports that are outside of my centers airspace
that get rejected by my computer. They can put in flight plans with
those intersections that are not in my centers airspace and they will
show up on the flight plan. I can't do that with my FDIO.



then the controller has to sort it out.

There's no sorting out. If the flight plan comes out of my strip
printer then the computer won't have a problem with it.


This is
particularly a problem if the pilot has filed "direct" and ignored
the AIM suggestions about including navaids in each center's airspace
on their direct routing.

No. File direct anywhere. If the computer takes it it will print out
and cause no problems anywhere down the line. You will have better luck
filing to really small Podunk muni with DUATS or thru AFSS than I will
from my FDIO.



Conclusion: filing to an IAF makes no sense unless that IAF is an
H-class VOR or otherwise likely to be in the originating ATC
facilities database.

And I would also add it is convenient to your flight.