Being asked to "verify direct XXX"

On Sat, 16 Apr 2005 04:29:32 GMT, Paul Folbrecht
wrote:

My two-part question is 1) Should I be concerned at all by being asked
such a question by ATC?

Perhaps. It may just be controller confusion (can't remember if you
were cleared direct or not). However, there is a very good chance
your groundtrack is not matching up with 'direct ABC VOR', so the
controller is either prompting you to get back on course or wants to
make sure that you are indeed going to ABC VOR.

Does your GPS have an HSI display? It makes holding the course much
easier.

And 2) Just _what_ is the IFR "heading tolerance", anyway??

I don't think there is one (other than as defined by the PTS during
your IR checkride). The only way a controller knows if you are off
heading is if your ground track changes. Given the sample/update rate
of radar displays, I would think most short term heading deviations go
unnoticed.

***Question for the controllers on the newsgroup: How often does your
radar display update? Every 15 seconds? 30?

Realistically, an occasional heading excursion of 10degrees should not
matter (grabbing a chart), but I do think 25 is excessive (even if
only temporary). If you are in IMC and drifting that far off heading,
you need to work on your scan and control, or limit the activities
that cause the distraction (grabbing maps, lunch, etc).

-Nathan

Oh, I agree entirely. I should have mentioned that was only once, and I
also might have mentioned that we had a total vacuum failure within 5
minutes of that and the DG may already have been spinning down (we were
in VMC with me wearing foggles).

I got quite good at holding heading very accurately during my training.
I just have to learn to not let distractions interfere with that,
even momentarily.

Man, even a single-axis AP would be nice!

Realistically, an occasional heading excursion of 10degrees should not
matter (grabbing a chart), but I do think 25 is excessive (even if
only temporary). If you are in IMC and drifting that far off heading,
you need to work on your scan and control, or limit the activities
that cause the distraction (grabbing maps, lunch, etc).

-Nathan

On Sat, 16 Apr 2005 15:07:35 GMT, Paul Folbrecht
wrote:

Oh, I agree entirely. I should have mentioned that was only once, and I
also might have mentioned that we had a total vacuum failure within 5
minutes of that and the DG may already have been spinning down (we were
in VMC with me wearing foggles).

I got quite good at holding heading very accurately during my training.
I just have to learn to not let distractions interfere with that,
even momentarily.

As you pointed out earlier. Solo IFR in IMC without an AP is one of
the most demanding tasks in flying. It helps to have a non-pilot
friend in the right seat (to hand you maps or lunch!).

Man, even a single-axis AP would be nice!

I have a wing-leveler in my Cherokee 180. Although wing levelers
aren't the greatest, they do keep the plane upright and generally
pointed in the same direction. I am glad to have it, but of course
would like a 2-axis coupled AP.

-Nathan