On 18 Dec 2006 11:40:07 -0800, wrote:


Matt Barrow wrote:
wrote in message
ps.com...

M wrote:
RST Engineering wrote:
C'mon Roy, you've been around airplanes long enough to know the real
answer -- "Why that compass card has been in the airplane since I
bought
it."


Same reaction here. Doesn't everyone here have at least two GPS's
onboard that show a ground track bearing 10 times better than the
compass?

No, and you won't either next time your alternator decides to go
south.

Gee, Dan! Do you sleep in a house? You know, you'd be squashed like a bug
when your roof collapses!


Don't be dumb. The magnetic compass is legally required because it
operates independently of any electrical supply, unlike any other
navigational doodad you might have. And in some areas we fly here in
Canada, the mag compass has saved a lot of lives when the rest of the
goodies failed. An accurate compass and a pilot able to use it is
absolutely necessary for finding the way home when other stuff quits,
especially the GPS. There are no other navaids in much of this country.
When the visiblility is low, you can miss your airport by a mile or two
and never see it. A one-degree error on a 60-mile track is a mile off
course, so we teach some of our navigation exercises in an airplane
with nothing more than a compass. We have had alternator failures
several times over the years, even with carrying out the 500-hour
alternator inspections.
On the other hand, the compass is mostly useless in the far
North due to magnetic dip. Up there pilots sometimes keep the "sun's
true bearing" tables aboard.

Dan

I've flown all over ontario wit just a map and compass in an old
champ. If you're reading the map the compass doesn't have to be ver y
accurate. In fact unlessyou're spending half your tme playing with
your E6B you can't correct for wind drift within 1 degree so why even
try. I now fly with a portable GPS and I like it a lot. It makes me
very lazy about plotting my course but I still have to know where I am
on the map.