Being asked to "verify direct XXX"

ATC can't see your heading, just your ground track. They would have no way
of knowing that you are off-course by a "couple of degrees."

Bob Gardner

"Paul Folbrecht" wrote in message
...
I'm a new IFR pilot, having gotten my ticket end of January.

One thing I've quickly picked up on is that ATC pretty much expects
everybody to be able to navigate direct. If you tell them you've got a
VFR GPS (in your remarks), they'll happily give you direct clearances and
instructions while airborne. I've learned to deal with that (by really
learning how to use my GPS), though I really still wonder about the whole
thing and marvel at the fact that they'll expect me to navigate under IFR
with this thing without a current database (I don't keep the DB current
and there's certainly no reason at all they should expect that I do). (I
am planning to do somewhat regular DB updates from here on out, but it's
not going to be every month.)

Anyway, on to my question. A couple times now, when I've been navigating
direct, either to a fix or airport identifiable by VORs or one that isn't
(such as an uncontrolled field with no navaid), I've been asked to "verify
direct XXX" when I'm off course by a quite small amount - no more than 10
degrees. Or, perhaps, I've gotten off course a bit and have a larger
heading correction (20-25 degrees) in to get back on track, momentarily.
I've never had a controller sound annoyed, but it does concern me a bit
that they see fit to more or less ask "Are you sure you know where you're
going"??

I've vowed to put a stop to this, and I have realized that I should
probably pay even closer attention to my heading. I am meticulous about
holding alt but, obviously, heading is important too. Flying single-pilot
IFR with no autopilot, with turbulence, it can be a challenge in those
moments where the workload is high for a bit..

My two-part question is 1) Should I be concerned at all by being asked
such a question by ATC? And 2) Just _what_ is the IFR "heading
tolerance", anyway?? Meaning, what sort of heading deviance is large
enough that you can be violated for it? Does such a figure even exist? I
expected this to be something fairly simple to find in the regs and it was
not.

TIA.

~Paul Folbrecht
~PP-SEL-IA
~'79 C152
~MWC

"Bob Gardner" wrote in message
...

ATC can't see your heading, just your ground track. They would have no way
of knowing that you are off-course by a "couple of degrees."


Sure they do. If the observed track is other than the cleared route the
aircraft is off course.

Nitpick, Steve. This is another example of a pilot thinking that ATC sees an
image of the airplane rather than a data block.

I'll be at the NATCA meeting in May...will you? I'm neither a controller nor
a NATCA member, but I go anyway.

Bob Gardner

"Steven P. McNicoll" wrote in message
ink.net...

"Bob Gardner" wrote in message
...

ATC can't see your heading, just your ground track. They would have no
way of knowing that you are off-course by a "couple of degrees."


Sure they do. If the observed track is other than the cleared route the
aircraft is off course.

"Bob Gardner" wrote in message
...

I'll be at the NATCA meeting in May...will you?


Nope.



I'm neither a controller nor a NATCA member, but I go anyway.


Why?

"Steven P. McNicoll" wrote in message
ink.net...

"Bob Gardner" wrote in message
...

I'll be at the NATCA meeting in May...will you?


Nope.



I'm neither a controller nor a NATCA member, but I go anyway.


Why?


Because it isn't just a NATCA meeting...

Chip, ZTL

"Chip Jones" wrote in message
ink.net...

Because it isn't just a NATCA meeting...


Odd, then, that that's what it's called.

"Steven P. McNicoll" wrote in message
link.net...

"Chip Jones" wrote in message
ink.net...

Because it isn't just a NATCA meeting...


Odd, then, that that's what it's called.



LOL, is not.... :-P

Chip, ZTL

Bob Gardner wrote:

ATC can't see your heading, just your ground track. They would have no way
of knowing that you are off-course by a "couple of degrees."

The only way ATC notices a 2 degree error is if where you are supposed
to be going happens to follow an airway.

My take is direct gives you the same horizontal and vertical tolerances
that an airway does. Which I think, is 100' of altitude variation
(actually they don't usually see it, unless it is 150' or more), and 2
miles to the right or 2 miles to the left.

However it ATC sees you are veering off course, the controller can ask,
as a way of getting your attention to the deviation (even though it may
still be withing tolerances). He sees you are veering off course and
wants you to correct. But that doesn't mean you have busted your
clearance.

Take ATC statements for what they say. He wants you to verify that you
are direct.

Also, don't get in the habit of hitting the direct to button, you
should actually fly back to your course and get back on your original
direct track, not keep making new direct to tracks.

If you do a lot of IFR flying, get the Howie Keefe (www.aircharts.com),
text updates. You can use these to see if any of the waypoints have
changed if you update your GPS when the Keefe system begins (March I
think). This way you will know if your waypoints are up to date, even
though the database may not be.

Newps wrote in message ...

The only way ATC notices a 2 degree error is if where you are supposed
to be going happens to follow an airway.



No, a controller can also compare the track to the route readout.