Absolute lowest altitude you can fly (legally)

Mxsmanic wrote:
Walt writes:

But, this is not a big deal, since you'll be using waypoints along the
way, and the heading between waypoints won't change enough to be a
worry. But, you'll probably notice that your true heading changes by a
degree or so from one waypoint to another.

This is an interesting point. I do see the heading towards a waypoint
change slowly over time, and I've naturally assumed that it was just
the wind. However, if the distance between waypoints is quite long, I
can see that the actual track to follow could change over time due to
the great-circle character of the track between the waypoints.
Unfortunately, I don't remember offhand how long the distance would
have to be before it would change by a degree or more at intermediate
latitudes.

That's the whole reason for waypoints. We live on a sphere but
dead-reckon on a flat surface.

So, for dead reckoning today it's not incidental at all.

Yes, _if_ someone is navigating by dead reckoning. My point was that
hardly anyone uses dead reckoning by hand these days. And as one
increases in latitude, the 1 degree = 1 minute relationship gets more
and more iffy, too.

Your original statement was about dead reckoning. That was what I was
responding to.

35 years ago I could whip up a comp for a celestial shot in less than a
minute. Today it would probably take me a week. Of course, we used an
Air Almanac and an H.O. 249 to take care of the pesky trig stuff, so it
was mainly adding and subtracting stuff involving the GHA of Aries.
:)

I'm sure most other pilots have the same problem--if they ever knew
how to do this in the first place, that is.

Just a teary-eyed remembrance from an old fart. I didn't expect much of
a response.


ANYWAY, if you're serious about plotting your course on a chart, know
what map projection you're using and the distance between waypoints.
Using a conical projection chart and a standard plotter will be plenty
accurate for any kind of dead-reckoning, no matter which direction
you're going.

Not very practical for me these days.

That wasn't my point. I thought you were interested in navigation. Try
reading Dava Sobel's _Longitude_. Fascinating read if you're really
interested in navigation, whether 300 years ago or present time.

--Walt (who is probably showing his age)

When you flew, the B-52 was an important part of the military's
aircraft inventory. Whereas today, the B-52 is an important part of
the military's aircraft inventory.


Nice putdown.

I gave you some tantalizing clues about navigation. Pursue them or
ignore them. Up to you.

--Walt