The Comair crash reminds me...

Jim Macklin wrote:

Actual runway details are on the instrument approach charts,
including direction to the degree and elevation and slope.

Yep, I am aware of that. I was curious whether it is common for pilots to
pull out their instrument charts after learning of or deciding upon what
runway is in use/to use at an unfamiliar airport. It seems to me that with
the workload of pre-taxi, taxi, and pre-takeoff checklists, this item is
probably not a task many pilots perform. Or do they?

In my case I have a slaved HSI in my Bonanza, so I had been quickly
comparing the HSI heading to the runway number to see if it is within ten
or so degrees of the runway number as part of the "lights, camera, action"
taking-the-runway mnemonic.

--
Peter

The slaved compass is corrected so as many errors
(deviation) are corrected and variation is also corrected as
much as possible too, so the slaved compass may be reading
different from the whiskey compass unless you apply the
compass correction card FOR-Steer to get a more accurate
setting for the HI. But the whiskey compass is not supposed
to have any error greater than 10 on any heading. Often the
compass is swung with the electrical and radios running. It
seems that swinging the compass should be done with the
electrical system dead and the radios off, that is when I'd
want the most accurate magnetic compass.


"Peter R." wrote in message
...
| Jim Macklin wrote:
|
| Actual runway details are on the instrument approach
charts,
| including direction to the degree and elevation and
slope.
|
| Yep, I am aware of that. I was curious whether it is
common for pilots to
| pull out their instrument charts after learning of or
deciding upon what
| runway is in use/to use at an unfamiliar airport. It
seems to me that with
| the workload of pre-taxi, taxi, and pre-takeoff
checklists, this item is
| probably not a task many pilots perform. Or do they?
|
| In my case I have a slaved HSI in my Bonanza, so I had
been quickly
| comparing the HSI heading to the runway number to see if
it is within ten
| or so degrees of the runway number as part of the "lights,
camera, action"
| taking-the-runway mnemonic.
|
| --
| Peter

Jim Macklin wrote
The slaved compass is corrected so as many errors
(deviation) are corrected and variation is also corrected as
much as possible too,

SAY WHAT!!!! How does one fly an ATC assigned heading if VAR
has been 'corrected' out?

Bob Moore

"Bob Moore" wrote in message
. 122...
Jim Macklin wrote
The slaved compass is corrected so as many errors
(deviation) are corrected and variation is also corrected as
much as possible too,

SAY WHAT!!!! How does one fly an ATC assigned heading if VAR
has been 'corrected' out?

Probably the same way you do it when there's a wind. ATC assigns you a
heading. If that doesn't provide the track they want, they assign a new
one, adjusting for the error in the track.

They don't care what your heading indicator is telling you. They care that
you follow it consistently.

(Note: I don't actually know anything about how a slaved compass is
corrected...seems to me that variation and local deviation (that is, not due
to the aircraft installation itself) are not things one could usefully build
into a slaved compass. But assuming the slaved compass IS correcting for
all manner of things, there's no reason to believe it would cause a problem
with ATC).

Pete

The flux valve is usually located well away from steel and
electrical components, so it avoids many deviation errors.
It also is designed to be more accurate and reduce turning
errors sent to the indicator.


"Peter Duniho" wrote in
message ...
| "Bob Moore" wrote in message
| . 122...
| Jim Macklin wrote
| The slaved compass is corrected so as many errors
| (deviation) are corrected and variation is also
corrected as
| much as possible too,
|
| SAY WHAT!!!! How does one fly an ATC assigned heading
if VAR
| has been 'corrected' out?
|
| Probably the same way you do it when there's a wind. ATC
assigns you a
| heading. If that doesn't provide the track they want,
they assign a new
| one, adjusting for the error in the track.
|
| They don't care what your heading indicator is telling
you. They care that
| you follow it consistently.
|
| (Note: I don't actually know anything about how a slaved
compass is
| corrected...seems to me that variation and local deviation
(that is, not due
| to the aircraft installation itself) are not things one
could usefully build
| into a slaved compass. But assuming the slaved compass IS
correcting for
| all manner of things, there's no reason to believe it
would cause a problem
| with ATC).
|
| Pete
|
|

"Jim Macklin" wrote in message
news:_lOIg.6238$SZ3.83@dukeread04...
The flux valve is usually located well away from steel and
electrical components, so it avoids many deviation errors.
It also is designed to be more accurate and reduce turning
errors sent to the indicator.

But there's no way, absent some sort of absolute position information (eg
GPS) and a detailed database, to ascertain deviation due to local geology or
other external magnetic interference, nor due to magnetic variation (which
was Bob's point).

Of course, my point is that correcting those errors isn't relevant to ATC.
They don't care if your compass is actually right or not. They just care
that you can hold it to a specific heading. But I think it's fair to
comment on the statement that "the slaved compass is corrected so
as...variation is also corrected". That's clearly just not true, at least
in most installations (I suppose there's at least one GPS-based slaved
compass setup in which it is corrected...never say never...but generally,
this isn't used)

Pete

Sorry didn't mean to say it like that, compass deviation
correction. I was thinking about the swinging process,
flying a heading on a cardinal course (government surveyed
roads on sections lines are true N-S-E and W. Variation is
applied when setting the HI to get the local magnetic, then
turns are made with the HI and the compass read to determine
the deviation.

Sorry for being tired when I misspoke.


"Bob Moore" wrote in message
. 122...
| Jim Macklin wrote
| The slaved compass is corrected so as many errors
| (deviation) are corrected and variation is also
corrected as
| much as possible too,
|
| SAY WHAT!!!! How does one fly an ATC assigned heading if
VAR
| has been 'corrected' out?
|
| Bob Moore

Jim Macklin wrote:
The slaved compass is corrected so as many errors
(deviation) are corrected and variation is also corrected as
much as possible too, so the slaved compass may be reading
different from the whiskey compass unless you apply the
compass correction card FOR-Steer to get a more accurate
setting for the HI. But the whiskey compass is not supposed
to have any error greater than 10 on any heading. Often the
compass is swung with the electrical and radios running. It
seems that swinging the compass should be done with the
electrical system dead and the radios off, that is when I'd
want the most accurate magnetic compass.

Why do you want your compass to be most accurate when your airplane
isn't being used?

Matt

It seems that swinging the compass should be done with the electrical system dead and the radios off, that is when I'd want the most accurate magnetic compass.
Why do you want your compass to be most accurate when your airplane isn't being used?

I think he means that when all the electrical systems (& DG) go south
but you're still "up there, wishing you were down here", is when you
want the mag compass to be dead on.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Because it is in flight and has had a total electrical
failure, all I have to navigate with is my wrist watch and
the magnetic compass. In that case, I want the compass to
be the most accurate as possible. When the radios work, I
can use the VOR/GPS and even radar vectors, when all that is
dead, the compass will get you there IF it is accurate. A
10 degree error will but you off course 10 miles every 60
[57.3] miles you fly. If visibility is 5 miles an
inaccurate compass will leave you lost at sea. Maybe you
will find the coastline of the continent, but if you're hope
is land fall on an island, you need an accurate compass.



"Matt Whiting" wrote in message
...
| Jim Macklin wrote:
| The slaved compass is corrected so as many errors
| (deviation) are corrected and variation is also
corrected as
| much as possible too, so the slaved compass may be
reading
| different from the whiskey compass unless you apply the
| compass correction card FOR-Steer to get a more accurate
| setting for the HI. But the whiskey compass is not
supposed
| to have any error greater than 10 on any heading. Often
the
| compass is swung with the electrical and radios running.
It
| seems that swinging the compass should be done with the
| electrical system dead and the radios off, that is when
I'd
| want the most accurate magnetic compass.
|
| Why do you want your compass to be most accurate when your
airplane
| isn't being used?
|
| Matt