"Bob Gardner" wrote in message . net...
I know Don Brown. He is a good 'ol country boy, and an entertaining
writer, but he is not a pilot. His aviation world is circumscribed by
the AIM and Air Traffic Control Handbook, with no latitude (no pun
intended) allowed. His Avweb column about filing IFR is almost perfect,
but there are airplane-owning controllers around the country who will
tell you that host computers throughout the system recognize lat-longs,
while a radial-distance from a VORTAC several hundred miles away might
get bounced because the VORTAC is not in the host computer. Keep filing
lat-longs where appropriate even if you never get up to FL390.

Bob,

I think two of Don's concerns with lat-longs a
1) they provide ATC with no information about what direction you're
headed, so coordination with other facilities is difficult. In fact,
initial separation is problematic.
2) ATC apparently has no means to verify a lat-long against an
airport identifier or navaid to ensure that the lat-long was entered
correctly. Serious lack of backup or verification redundancy.

I don't know about you, but I don't want to be in either place.

My suggested solution for filing GPS direct is:
1) provide a VOR radial-distance waypoint which will be recognized --
one w/in the facility's boundry is a good bet. That way ATC knows
which direction you're headed from a waypoint which will be in their
host computer, and coordination is easier for them
2) put a radial-distance from a VOR near your destination into your
flight plan. if you're crossing several centers, make sure there's
one in each center.

I note that the above does not fulfil the letter of the AIM for
direct flights, which require that a direct flight begin and end
over a ground-based navaid (at least as I read it) but I feel
it fulfills the spirit, in that it allows ATC to know which way
I'm headed without guessing and to verify any lat-longs in a
straighforward way. I object to the letter of the AIM because
AFAIK VORs near busy airports qualify as "designated collision
points" and I see no reason to detour and fly over one when it's
not necessary.

I also note that DUATS flightplanner direct routing for GPS/RNAV
makes the above stone-simple because it spits out a list of such
waypoints along one's route of flight.

3) put some comment about a major, recognizeable waypoint
into your remarks section. ie if I'm flying from s. FL to our new
homebase airport, it's a cinch that the Miami Center computer won't
have a clue where 1H0 is, but if I put "remarks 1H0 7 SW KSTL"
hopefully everyone in the ATC system now grasps which way
I'm intending to fly. If the lat-long has me flying in the opposite
direction, there's clearly a mistake.

This said: I don't understand your comment about why one should
file lat-longs. Yes, VORS outside a center's airspace might
not be in the host computer, but this doesn't stop pilots from
flying Victor airways or direct VOR routing which includes
VORs the ATC computer for the facility originating the flight
won't recognize. What I know about ATC host computers could be
printed on a penny and lost, but surely they have some mechanism
for accepting "I don't know where that VOR is, but the routing
through my part of the system looks OK so off you go".

So it seems to me that the lat-long vs. a VOR-radial-distance
waypoint becomes an issue only if you have NOT included some
waypoint within the airspace of each facility along the way.
And that's a no-no, both in terms of the AIM's instructions
for filing direct and in terms of filing in a manner ATC can
deal with easily.

Perhaps I'm just dense here, but we file GPS direct to obscure
airports (along with the pound of flesh nearest Don Brown's
heart, I assume, sorry ) all the time. We just make sure to
include at least one VOR degree-distance waypoint for each facility
we cross, lately we've also taken to including a remark about
our destination vs. a major airport if that's possible. We've
never had anyone request a lat-long from us.

In a sane world, of course, each controller would be able to
instantly convert a lat-long into some bearing from a recognizeable
navaid or airport. It could be done on a used $50 Palm Pilot.
But that would make too much sense.

Best,
Sydney