Why are headings still magnetic?

Paul Hirose writes:

Maybe someone else has already mentioned that VORs and TACANs are
aligned so their radials are close to the magnetic direction. Changing
them to true would be pretty expensive and disruptive.

They have to be changed if the magnetic poles drift, too. In some
locations this may occur as often as once every few years, if an
accuracy of plus or minus half a degree is required.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Stubby writes:

I believe all U-2s have been retired. The satellite folks are winning
the high altitude intel game. Too bad the U-2 was a nice plane (glider?
rocket???).

The U-2 is still used, oddly enough (whereas the SR-71 is not, at
least officially).

It's a conventional aircraft, but with some characteristics and uses
that make it extremely difficult to fly. It is an aircraft with a
distinctive "coffin corner," that is, in a typical mission cruise
configuration, its maximum speed is only a few knots higher than its
stall speed, and if the speed is not precisely held within those
narrow limits, trouble results.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Stubby writes:

I met a sea captain that piloted an old ship full of refugees from
Latvia to Nova Scotia in 1939 with only a sextant and magnetic compass.
And he said it was overcast most of the time.

Lindbergh had only a compass and a maritime map (with his hand-drawn
route on it) that he had bought in a shop in San Diego to get him from
New York to Paris.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Thomas Borchert writes:

And having true heading (and only that) changes this problem how?

It doesn't. But true north doesn't move, and it's right at the top of
standard maps.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Stubby writes:

Interesting, alarmist speculation.

What is alarmist about it?

--
Transpose mxsmanic and gmail to reach me by e-mail.

Grumman-581 wrote:
wrote in message
oups.com...
Finally, what problem would it solve? The shifting of
the Earth's magnetic poles is slow, relatively
predictable, and something we have lived with for
awhile. While true headings may be more elegant
and stable over the very long term, that elegance
doesn't add much practical value.

It's the typical case of a solution in search of a problem...

This is like the remark from non-aviators why we still use the archaic
units of nautical miles and knots. I have also had people comment why I
continue to use "clunky old Linux" instead of windows. The latter one
was from a highly educated person in Engineering. Clearly, these
types of remarks are due to misconceptions or lack of knowledge. I am
glad these people don't run the world (or may be they already do:-))

Mxsmanic,

It doesn't. But true north doesn't move, and it's right at the top of
standard maps.


Dodging and back pedaling again. You really ARE like this, are you?


--
Thomas Borchert (EDDH)

Andrew Sarangan writes:

This is like the remark from non-aviators why we still use the archaic
units of nautical miles and knots.

That is a different issue. Nautical miles and knots are stable and
need not be changed because aviation is effectively isolated from
other domains in which units of measure are required. In contrast,
magnetic poles move, and magnetic compasses depend on a magnetic field
that not only moves on its own throughout the planet but is also
distorted locally and regionally.

I have no problem with using nm and kts in aviation, or even with
using pounds for fuel, as long as everyone is on the same page.
Trying to switch units has sometimes had tragic results.

--
Transpose mxsmanic and gmail to reach me by e-mail.

On Sat, 09 Sep 2006 00:09:20 +0200, Mxsmanic
wrote:

Thomas Borchert writes:

And having true heading (and only that) changes this problem how?

It doesn't. But true north doesn't move, and it's right at the top of
standard maps.

Except that apparently true north DOES move. The tsunami/earthquake of
a year and a half ago reportedly caused the north pole to shift about
an inch as well as decreasing the length of a day. Just goes to show,
you can't depend on anything.

RK Henry

RK Henry writes:

Except that apparently true north DOES move. The tsunami/earthquake of
a year and a half ago reportedly caused the north pole to shift about
an inch as well as decreasing the length of a day. Just goes to show,
you can't depend on anything.

All earthquakes cause such effects. However, if they produce changes
that are below the resolution threshold of avionics, they aren't a
problem. The magnetic pole, on the other hand, moves perceptibly over
time--enough to require new charts and new regulation of stations and
instruments.

--
Transpose mxsmanic and gmail to reach me by e-mail.