On Thu, 17 Apr 2008 02:03:18 GMT, (Drew
Dalgleish) wrote:

On Wed, 16 Apr 2008 05:19:27 +0000 (UTC),
(Alan) wrote:

In article (Drew Dalgleish) writes:

My home airport has a compass rose and I use that. Taxiing aroud and
getting lined up on each heading takes me quite a bit longer than
that. Having a helper would speed things I'm sure but if we consider
man hours since the OP was about mechanics time then double your
15minutes.

It is easier to shut down and just turn the plane from heading to
heading manually.

I was going to ask how do you know if it's an accurate land
compass but it occurs to me that a GPS would do the job and then you
could do it by yourself .

How?

A GPS knows where it is, not which way it is facing.


Alan
Do it while flying. The GPS know which way it's going.

You really don't seem to understand -- heading and track are two
different things. They are only aligned if you are flying directly
into, or away from, the wind.

So your GPS is pretty well useless in flight for aligning a compass,
as you can never tell precisely the wind direction aloft. Certainly
not within the +/- 3 degrees that you should be trying to calibrate
against.
--
Jay (remove dashes for legal email address)