Absolute lowest altitude you can fly (legally)

Stefan writes:

And what exactly in this reglementation is not ICAO conform?

I don't know; that wasn't the question. The question was whether or
not the French still use metres in aviation, and they obviously do,
because it's right in the regulations.

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

Mxsmanic,

I know, in Germany everything is prohibited, except that which is
allowed.


More areas of life you have no clue about but still show arrogance
toward. Sad.

Very interesting how you resort to personal attacks more and more.

--
Thomas Borchert (EDDH)

Mxsmanic wrote:
writes:

Knots are not dimensionless in aviation. A knot is one nautical
mile per hour, and that nautical mile is the distance corresponding to
one minute of latitude at the equator.

Yes, but that is largely incidental today, particularly for east-west
movements away from the equator. Anyone using that relationship for
dead reckoning, for example, can get into trouble if he's not very
careful.

No, it's not incidental today. Back in my dead-reckoning days in the
Air Force we used Lambert Comformal charts, which uses a conical
projection. Using 1nm for dead-reckoning going east-west (across
longitude) was plenty accurate, until you got into the extreme northern
latitudes (which is where grid navigation came into play). But even
there, distance across longitude isn't necessarily the problem; heading
is.

And, look at a U.S. sectional chart. It uses Lambert Conformal conic
projection, and using 1nm for dead reckoning east-west (longitude) is
plenty accurate. You won't get into trouble.

Now, let's say you plan a flight across the U.S. from New York City to
Los Angeles. You'll be using (guessing here) maybe seven or eight
different sectional charts. Each has a different conical projection
point. So, even if, on the chart, you are plotting your route in a
"straight" line, you are really approximating a Great Circle route, and
your no-wind heading (true or magnetic, makes no difference) will be up
to several degrees different when you arrive in Los Angeles (compared
to your departure heading in New York). Obviously, I'm ignoring
magnetic variation here.

This is REALLY apparent when flying from, say, San Francisco to Tokyo.

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 applies to ONC and JNC charts too, and it worked fine for our
overwater navigation in KC-135's.

So, for dead reckoning today it's not incidental at all. Of course, if
you use a GPS or FMS as your primary navigation source it is, since the
map projections are taken care of by the computer in your box.

Anyone using lat/long and some spherical trig (like the old guys
who crossed oceans used sextants to determine their position) will
make use of these things.

I don't think too many pilots use sextants today. I think an
increasing number of pilots don't know how to do anything except look
at a moving map display, or set an autopilot.

The lazy ones
among us (or like me, the ones really poor at math) will use GPS, which
does the same thing.

Yes. But what you don't use, you lose. And I don't think pilots are
taught how to use sextants, anyway. Although I've heard that early
airline navigators and pilots used them--which is why some older
aircraft have little windows above the pilots, for shooting the stars.

sigh
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.
:)

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.

Now, flying an ARA into Thule, Greenland is a whole different animal.
:)

--Walt (who is probably showing his age)

Wolfgang Schwanke wrote:

It's really the Americans who do something different, and used their
power to force their ways on the rest of the world. Surely metric is
preferrable all other things being equal. It's not a big issue in
practice, but statments like the above are tinted by national prejudice
and should not be tolerated.

Regards

--
__o
http://www.wschwanke.de/ _'\,_ C'est le tour de
France!
(_)/ (_)

Hey, c'mon, that foot-and-pound system was forced on us by the British.
It's all their fault!

IIRC, there was a big push in the '70's or '80's in the U.S. to start
moving to the metric system, since it really is more logical. But,
there was a big push back from the general American public who liked
their feet and had no desire to transform them into meters. :)

As was mentioned previously by That Poster We Will Not Name, the unit
of measurement in aviation doesn't really matter all that much. FL350
could be 35,000 feet or meters, but as long as everyone uses the same
unit of measurement it doesn't really make any difference.

Now, when I flew a gunship (AC119K) in SE Asia, we used klicks and
meters as our unit of measurement (for firing solutions at least). I
guess I could use this as evidence of an insidious attempt by
Europeans, backed by the U.N., to force a unit of measurement on the
American people they don't really want. A guerrilla war type of thing.

But, I won't, because it's stupid.

To wrap this up, I'll just say one thing: a football field should
ALWAYS be 100 YARDS long.

Comments?

:)

--Walt (with tongue firmly in cheek)

Walt schrieb:

Hey, c'mon, that foot-and-pound system was forced on us by the British.
It's all their fault!

Yeah, but at least, they have reasonable gallons.

IIRC, there was a big push in the '70's or '80's in the U.S. to start
moving to the metric system, since it really is more logical. But,
there was a big push back from the general American public who liked
their feet and had no desire to transform them into meters. :)

The irony is that the metric system was forced some 200 years ago to the
unwilling European public by argument of sheer force.

Stefan

Neil Gould wrote:
Recently, Walt posted:

To wrap this up, I'll just say one thing: a football field should
ALWAYS be 100 YARDS long.

Comments?

I guess that depends on what you mean by "football field". |-0

Neil

My point exactly. :)

--Walt

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.

Of course, if the waypoints were on the Equator or exactly
north-south, there would be no change in heading.

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.

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.

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.

--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.

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

Walt writes:

Now, when I flew a gunship (AC119K) in SE Asia, we used klicks and
meters as our unit of measurement (for firing solutions at least).

What is a klick?

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

Mxsmanic,

What is a klick?


One kilometer. 1000 meters. One of those ridiculous French things...

--
Thomas Borchert (EDDH)

Recently, Walt posted:

To wrap this up, I'll just say one thing: a football field should
ALWAYS be 100 YARDS long.

Comments?

I guess that depends on what you mean by "football field". |-0

Neil