Compass swinging?

I've got AC 43.13-1B, which describes the procedure to swing a compass.
What I can't find is the bureaucratic stuff -- who can do it (any pilot?),
and what paperwork follow-up is required (airframe logbook entry, or is
just making the new compass card sufficient?).

This is probably something best left to someone with experience to avoid the
frustration of making interacting adjustments until you get it right. I had
the avionics tech do it for me at my last annual. He used test tools to
generate a magnetic field instead of actually taking the plane out onto a
compass rose on the ramp. The guy did a superb job.

--
Best Regards,
Mike

http://photoshow.comcast.net/mikenoel

"Roy Smith" wrote in message
...
I've got AC 43.13-1B, which describes the procedure to swing a compass.
What I can't find is the bureaucratic stuff -- who can do it (any pilot?),
and what paperwork follow-up is required (airframe logbook entry, or is
just making the new compass card sufficient?).

On Fri, 24 Nov 2006 22:00:24 -0700, "Mike Noel"
wrote:

This is probably something best left to someone with experience to avoid the
frustration of making interacting adjustments until you get it right. I had
the avionics tech do it for me at my last annual. He used test tools to
generate a magnetic field instead of actually taking the plane out onto a
compass rose on the ramp. The guy did a superb job.


I have never heard of that method being used, but in principle, I don't like
it! It is always best to calibrate something under the same conditions in
which it will be used. Simulating the earth's magnetic field is just adding
one more approximation to the calibration.

First: Just how did your avionics tech align the generated field with the
airplanes longitudinal axis? How accurately? How could you tell?

Second: How did the tech adjust the generated field to be the same strength
as the earth's magnetic field? It would have to be, or the compass
ajustments will not be correct.

Third: How did your tech eliminate the earth's magnetic field from
influencing the compass during the swinging? Seems your compass was
compensated in the presence of two magnetic fields -- one of which won't be
there when you are flying.

I'm more than a little suspicious about the technique.

Can't give a helpful answer. I just know how he told me he did it and that
the results were excellent.

--
Best Regards,
Mike

http://photoshow.comcast.net/mikenoel

"Jay Somerset " wrote in message
...
On Fri, 24 Nov 2006 22:00:24 -0700, "Mike Noel"
wrote:

This is probably something best left to someone with experience to avoid
the
frustration of making interacting adjustments until you get it right. I
had
the avionics tech do it for me at my last annual. He used test tools to
generate a magnetic field instead of actually taking the plane out onto a
compass rose on the ramp. The guy did a superb job.


I have never heard of that method being used, but in principle, I don't
like
it! It is always best to calibrate something under the same conditions in
which it will be used. Simulating the earth's magnetic field is just
adding
one more approximation to the calibration.

First: Just how did your avionics tech align the generated field with the
airplanes longitudinal axis? How accurately? How could you tell?

Second: How did the tech adjust the generated field to be the same
strength
as the earth's magnetic field? It would have to be, or the compass
ajustments will not be correct.

Third: How did your tech eliminate the earth's magnetic field from
influencing the compass during the swinging? Seems your compass was
compensated in the presence of two magnetic fields -- one of which won't
be
there when you are flying.

I'm more than a little suspicious about the technique.

ps Check out:

http://www.firstmarkaerospace.com/standbycompass.asp

--
Best Regards,
Mike

http://photoshow.comcast.net/mikenoel

"Mike Noel" wrote in message
. ..
This is probably something best left to someone with experience to avoid
the frustration of making interacting adjustments until you get it right.
I had the avionics tech do it for me at my last annual. He used test
tools to generate a magnetic field instead of actually taking the plane
out onto a compass rose on the ramp. The guy did a superb job.

--
Best Regards,
Mike

http://photoshow.comcast.net/mikenoel

"Roy Smith" wrote in message
...
I've got AC 43.13-1B, which describes the procedure to swing a compass.
What I can't find is the bureaucratic stuff -- who can do it (any
pilot?),
and what paperwork follow-up is required (airframe logbook entry, or is
just making the new compass card sufficient?).

"Mike Noel" wrote in message
. ..
ps Check out:

http://www.firstmarkaerospace.com/standbycompass.asp


Also, this thing is much less prone to errors:
http://www.aircraftspruce.com/catalo...rd_compass.php
and http://www.pai700.com/index.html

"Matt Barrow" wrote in message
...

Also, this thing is much less prone to errors:
http://www.aircraftspruce.com/catalo...rd_compass.php
and http://www.pai700.com/index.html


Less prone to what kind of errors?

"Stan Prevost" wrote in message
...

"Matt Barrow" wrote in message
...

Also, this thing is much less prone to errors:
http://www.aircraftspruce.com/catalo...rd_compass.php
and http://www.pai700.com/index.html


Less prone to what kind of errors?
Turning, acceleration, deceleration...

On Sat, 25 Nov 2006 16:14:36 -0700, "Matt Barrow"
wrote:


"Mike Noel" wrote in message
...
ps Check out:

http://www.firstmarkaerospace.com/standbycompass.asp


Also, this thing is much less prone to errors:
http://www.aircraftspruce.com/catalo...rd_compass.php
and http://www.pai700.com/index.html

I've had a vertical card compass for years. The Deb had one in it when
I go it so I'd hardly call it a new, let alone "totally new" concept.
Like a whisky compass it does not give the proper heading at all
times. You still have the lead and lag in turns and it won't set
still in turbulence, but it has far less movement than the whisky
compass in turbulence.

Swinging one is about the same. Just don't use runway headings unless
you know they are right. Ours are about 6 degrees plus so 360 is
really 006 and 060 is really 066. Hence the compass rose at some
airports and that set of tools in the instrument shop.





Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

"Roger" wrote in message
...
On Sat, 25 Nov 2006 16:14:36 -0700, "Matt Barrow"
wrote:


"Mike Noel" wrote in message
m...
ps Check out:

http://www.firstmarkaerospace.com/standbycompass.asp


Also, this thing is much less prone to errors:
http://www.aircraftspruce.com/catalo...rd_compass.php
and http://www.pai700.com/index.html

I've had a vertical card compass for years. The Deb had one in it when
I go it so I'd hardly call it a new, let alone "totally new" concept.
Like a whisky compass it does not give the proper heading at all
times. You still have the lead and lag in turns and it won't set
still in turbulence, but it has far less movement than the whisky
compass in turbulence.

I'd say about one-fourth the movement in any case. What surprised me was how
much less overshoot/undershoot there was during turns. I suspect it's from
being mounted in a jeweled gimbal (?) which dampens movement, instead of
floating in water

The only times (I think) that a whiskey compass is any good is on the ground
or in dead still air during 1.0G accell/decell.

How pilots used to navigate with them alone (wait for some cementhead to say
"they used watches and maps, too") is a testament to their skills.