Do you use your magnetic compass?

On any airplane I fly, if the mag compass is not within 5 degrees of
accuracy, I don't fly the plane, it's that important!

The mag compass is the primary navigation device in my Champ, so if the
mag compass is off, navigation can be a real bitch.

On Sat, 15 May 2004 12:33:25 GMT, "Roger Long"
om wrote:

A recent compass swing on our plane has turned up some opinions about
magnetic compasses that are surprising to me..

A club member has asked me why we spent money to have a 14 degree error
removed from our compass since it is just a back up instrument if everything
else quits. He just sets the DG to the runway heading on takeoff and uses
that. A couple of 360 in our 172 to look at something on the ground will
put our DG 15 -20 degrees off and it drifts about that much each hour. That
doesn't seem to concern him.

An A&P I asked in another forum said he hopes his customers don't expect him
to get the compass closer than about 10 degrees. Our shop says 10 degrees
is what is allowed.


the australian standard is 5 degrees maximum error with an annual
compass swing.
most compasses will be well within that.

most common problem is a leaking diaphragm followed by some wear on
the spindle. both are easily repaired by someone knowledgable.

yes it does matter. when you need it most is a situation where you
cant recognise a damn thing below and will need to fly a known bearing
until something that you do recognise comes into view.

they are pretty reliable in a pinch since the earth's magnetic field
doesnt have an off switch :-)

Stealth Pilot

Actually, according to the discovery channel, the earth's poles are
weakening, and will ultimately reverse polarity...

Pilots everywhere are going to become very confused very quickly.

Most, though, will be most horrified when their toilet bowl flushes the wrong
way.


Stealth Pilot wrote in
:

they are pretty reliable in a pinch since the earth's magnetic field
doesnt have an off switch :-)

Stealth Pilot

Judah wrote:

Actually, according to the discovery channel, the earth's poles are
weakening, and will ultimately reverse polarity...

Pilots everywhere are going to become very confused very quickly.

Most, though, will be most horrified when their toilet bowl flushes the wrong
way.

Well, if that's what's going to horrify me most, then having my magnetic compass
become a flip-flop will be a non-event. I haven't made a habit of watching the stuff
in the toilet go down the drain in *many* years.

George Patterson
I childproofed my house, but they *still* get in.

Fortunately, it is estimated that this process will take between a few
years and a few hundred thousand. So while all experts seem to agree that
we are long overdue (it has been about 750,000 years since our last pole
swap, and supposedly it normally occurs about every 300,000), there is a
chance that you will not be required to revitalize your former pastime of
toilet-gazing too soon.

And as long as you have had your compass card upgraded before the process
is complete, it will indeed be a non-event. Just another FAA
Airworthiness Directive to comply with at your next annual...

"G.R. Patterson III" wrote in
:



Judah wrote:

Actually, according to the discovery channel, the earth's poles are
weakening, and will ultimately reverse polarity...

Pilots everywhere are going to become very confused very quickly.

Most, though, will be most horrified when their toilet bowl flushes
the wrong way.

Well, if that's what's going to horrify me most, then having my
magnetic compass become a flip-flop will be a non-event. I haven't made
a habit of watching the stuff in the toilet go down the drain in *many*
years.

George Patterson
I childproofed my house, but they *still* get in.

On Mon, 17 May 2004 01:13:50 +0000, Judah wrote:

Fortunately, it is estimated that this process will take between a few
years and a few hundred thousand. So while all experts seem to agree that
we are long overdue (it has been about 750,000 years since our last pole
swap, and supposedly it normally occurs about every 300,000), there is a
chance that you will not be required to revitalize your former pastime of
toilet-gazing too soon.

And as long as you have had your compass card upgraded before the process
is complete, it will indeed be a non-event. Just another FAA
Airworthiness Directive to comply with at your next annual...



Actually, there is a geologist that appears to make an argument that the
last time the poles switched, they switched over a period of 6-days, then
back again, and IIRC, switch yet again over some other short period of
time. Current computer models also seem to indicate that the switch can
actually take place in a rather small window of time. In the words of the
geologist (paraphrasing), if such a transition were to happen again, if
you were to closely watch your compass, you could actually watch your
compass follow the changing mangnet poles.

Supposedly, the solar winds, the atmosphere, and the remaining magnetic
fields during this transition may be enough to protect the earth from the
worst of the sun's radiation.

"Judah" wrote in message
...
Actually, according to the discovery channel, the earth's poles are
weakening, and will ultimately reverse polarity...

Pilots everywhere are going to become very confused very quickly.

Most, though, will be most horrified when their toilet bowl flushes the
wrong
way.

Nope. Flush direction is a rotational thing, not magnetic. Unless you have
magnetic water?
--
Jim in NC


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In article , Morgans
wrote:

"Judah" wrote in message
...
Actually, according to the discovery channel, the earth's poles are
weakening, and will ultimately reverse polarity...

Pilots everywhere are going to become very confused very quickly.

Most, though, will be most horrified when their toilet bowl flushes the
wrong
way.

Nope. Flush direction is a rotational thing, not magnetic. Unless you have
magnetic water?

A good chemical softener will take the iron right out of it (and make
your soap lather up, too). ;-)

My Dad bought a water softener in 1952. Didn't know what it was, but my
shorts got softer.

Mike $$$

"Morgans" wrote in message
...

"Judah" wrote in message
...
Actually, according to the discovery channel, the earth's poles are
weakening, and will ultimately reverse polarity...

Pilots everywhere are going to become very confused very quickly.

Most, though, will be most horrified when their toilet bowl flushes the
wrong
way.

Nope. Flush direction is a rotational thing, not magnetic. Unless you
have
magnetic water?

Although many killjoys like myself know this is an UL, you actually *can*
demonstrate the Coriolis effect in a large bowl of water. But...
http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html

Sure, flush direction is a rotational thing. But it's not an
earth-rotational thing.

-- David Brooks