Must file to an IAF?

Ron Rosenfeld wrote:

And if your destination does not have weather reporting? (Or even nearby
weather reporting) and has multiple IAF's?

Just so. Bigger airports will often be using more than one IAF
simultaneously, especially if the winds are not strong. The preferred
approach at my home airport in Ottawa (CYOW) is LOC (BC) 25, but ATC will
normally give you ILS 32 if you ask, especially if you're coming from the
south. When the weather goes down low, the wind tends to shift to the east,
and then they land ILS 07 or possibly LOC (BC) 14. The active approach can
change every few minutes in marginal weather.

It would be a futile exercise to file to an IAF, but filing to a STAR makes
sense, since you can pretty-much predict your STAR based on your direction
of arrival (at least in Ottawa).


All the best,


David

"Jim Baker" wrote in message ...
"Jeremy Lew" wrote in message
...
Doesn't filing to an IAF imply that you know before you take off which
approach you'll be flying? It seems almost useless, since the "in use"
approach may be something entirely different once you actually get there.
Am I missing something?

What you're missing Jeremy, IMO, is that you'll know, or should know, before
you leave on an IFR flight which RWY is probably currently active at the
airport by listening to your predeparture WX briefing and figuring which RWY
will most likely be active upon your arrival.

Just my opinion, but if you're making a flight of any duration (3-3 1/2 hrs)
weather has a way of changing esp. if it's low enough that an approach
looks likely.

That's not to say that a preflight wx briefing and a careful preflight
review of the most likely approach aren't of value -- they are.

But filing to an IAF for a particular approach just may not be a
reasonable idea, regardless of preflight wx and wx changes enroute.

If the airport is busy and has radar, the IAF may be the last place
you'll ever be directed to fly and the least desireable route to the airport.

If the IAF is not an H-class VOR, it's not likely to be in the ATC
database of the originating ATC facility if you're making a trip of
any duration, so filing to an IAF only bolixes the works.

IMHO, it's much better to look at the specifics of the situation
than to make a general rule like "file to an IAF".

If you have an ILS on board, for instance, pick the IAF as your last point
in the route of flight for an ILS approach serving the RWY you expect to be
active. That's the best you can do and is much better, IMO, than not making
any plan because the RWY might be different than the one you picked based on
the predeparture WX briefing.

It may be better than "not making any plan", but it's not necessarily a
realistic or reasonable plan.

Here's a specific example. Consider the ILS 26L approach into KSUS,
which one can look at online at AOPA or myairplane if one likes.
This is the favored runway and the runway into the most common wind
directions, so it's a reasonable guess if an instrument approach is
needed, that's the one.

There are two IAF. One is Troy (TOY), VOR to the E. It's not an
H-class VOR, and if I'm starting my flight in mid-Ohio or MN or
GA, ATC may or may not have TOY in the system. Moreover, to get
from TOY to SUS the direct route takes one right across the
approach paths into KSTL. Is that gonna happen, no. Is that what
I'd choose in the event of a comm failure, no way.

The other IAF is the LOM, Eaves, and the betting is good outside
KC center turf no ATC computer has heard of it.

Coming from the north, I'd file to STL, which is an H-class VOR
and a reasonable bet that most ATC computers have heard of it.
Coming from the south, I'd file to Meram, an airway intersection
south of Eaves, with a remark Meram is STL170018. Coming from
the E. or W. would depend on my exact heading -- might still be
the same. Again, reason, I think ATC computers are likely to know
where STL is so anything defined by STL is good.

My home airport, 1H0, is served by GPS approaches. Would I file to
one of those IAFs, no way. No ATC database outside the "home boys"
will ever have heard of them.

$0.02,
Sydney

Ron Rosenfeld wrote:
On Wed, 04 Aug 2004 20:24:44 GMT, "Geo. Anderson"
wrote:


Checkride next week. Discussion today: CFII and I remember somewhere
being told that an IFR flight plan must terminate at an IAF for the
destination airport. Seems logical. But where is this written? I
couldn't find it in the AIM. He found it in an old training manual of his.


I know of no such requirement for Part 91 flying. Block 9 of the FAA
flight plan, as described in the AIM, calls for the destination airport
identifier code (or name if the code is unknown), not for an IAF.

The IAF will be the last item in the ROUTE block.
The destination is still the airport.

On Thu, 05 Aug 2004 14:20:59 GMT, john smith wrote:

The IAF will be the last item in the ROUTE block.
The destination is still the airport.

Exactly. And the *destination* is where the flight plan terminates, and to
which you will be cleared.


--ron

"Geo. Anderson" wrote in message . ..

Checkride next week. Discussion today: CFII and I remember somewhere
being told that an IFR flight plan must terminate at an IAF for the
destination airport. Seems logical. But where is this written?


It isn't written anywhere that makes it a requirement. In most cases
where the IAF is not part of the enroute system the flight data
processing computer will not accept it anyway.



Further discussion, comm failu I am cleared for all approaches, I
leave the as-filed IAF on time, etc. BUT -- even though I may not have
a charted path from that IAF to all of the other approaches, I am still
permitted to use any of them. Under emergency authority, I guess I can
legally bumble my way to another IAF even though there is not an
official way to find it. Is that the rationale that lets me choose any
approach when leaving my one filed IAF?


This has been discussed in this forum ad nauseam. I suggest a Google
Groups search with NORDO as a keyword.

"Ron Rosenfeld" wrote in message
...

I know of no such requirement for Part 91 flying. Block 9 of the FAA
flight plan, as described in the AIM, calls for the destination airport
identifier code (or name if the code is unknown), not for an IAF.

Although it is acceptable, and maybe preferable, to file "via" an IAF,
there is no "requirement" of which I am aware. In addition, there are
approaches for which there are no feeder routes from the enroute
structure,
so a blanket requirement makes no sense.


Unless the IAF is also part of the enroute structure it is unlikely to be
stored in the flight data processing computer. Filing one will cause your
flight plan to be rejected at some point, until someone corrects it by
removing the filed IAF!

David Megginson wrote:

The point's well-taken, though. In the unlikely event that I went NORDO in
solid IMC *and* ATC lost RADAR at the same time, I might be at some extra
risk starting down earlier, though (hopefully) larger planes would still see
me on their TCAS if my transponder was working.

If ATC lost radar, wouldn't all transponders go dark to TCAS units? Of
course, this assumes only one radar is painting you at a time - which is
often untrue.
--
Bill "the Roadie" Carton

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.