Do all commercial aircraft that fly in and out of North America have
dual unit altimeters (hPa and inHg)?

(Pat Norton) wrote:

> Do all commercial aircraft that fly in and out of North America have
> dual unit altimeters (hPa and inHg)?

I don't know about that, but as regards to the metric system, I would
like to mention that using hPa is _not_ the recommended way. Although
the "h" prefix is formally part of the SI system, it's regarded as
unsuitable by many, including NIST.

In practice, using hPa means being just _nominally_ metric, i.e. using
actually millibars but under a different name. The odd thing is that
the correct kPa would be more practical.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

On Sun, 7 Mar 2004 16:18:10 +0000 (UTC), "Jukka K. Korpela"
> wrote:

(Pat Norton) wrote:
>
>> Do all commercial aircraft that fly in and out of North America have
>> dual unit altimeters (hPa and inHg)?
>
>I don't know about that, but as regards to the metric system, I would
>like to mention that using hPa is _not_ the recommended way. Although
>the "h" prefix is formally part of the SI system, it's regarded as
>unsuitable by many, including NIST.
>
>In practice, using hPa means being just _nominally_ metric, i.e. using
>actually millibars but under a different name. The odd thing is that
>the correct kPa would be more practical.

Amen.
http://ourworld.compuserve.com/homepages/Gene_Nygaard/hectopas.htm

This screwball unit is just a misguided effort to hang onto an
obsolete unit by cloaking it in a marginally SI name. It makes no
more sense than soils scientists measuring soil conductivity (or
whatever is the proper term for the quantity measured, I'm doing this
off the top of my head without checking the terminology used) in units
of "dS/m".

Can you figure out the ever-so-handy unit the soils scientists are so
desperately trying to salvage?

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

"Jukka K. Korpela" > wrote in message
. ..

> In practice, using hPa means being just _nominally_ metric, i.e. using
> actually millibars but under a different name. The odd thing is that
> the correct kPa would be more practical.

How can you possibly suggest that it would be more "practical" to use kPa?
There is an installed base of tens of thousands of altimeters in aircraft
out there that are calibrated in mbar. Describing them as hPa makes it
clear what the unit is for someone familiar with the SI, without risking
accidents through unit confusion.

The preference to use powers of 1000 is just a preference because
practicality and pragmatism is sometimes more important than an arbitrary
recommendation. This is a perfect example of where pragmatism should (and
does) win.

Julian Scarfe

"Julian Scarfe" > wrote:

> How can you possibly suggest that it would be more "practical" to
> use kPa?

Because one digit less is needed, and conversions are easier when
powers of 1,000 are used as normally.

> There is an installed base of tens of thousands of
> altimeters in aircraft out there that are calibrated in mbar.

This is not about calibration, this is about expressing physical
quantities. Besides, if the installed base of equipment were decisive,
each of us would still use one's country's inch, pound, or whatever
local measures were in use long ago.

> Describing them as hPa makes it clear what the unit is for someone
> familiar with the SI, without risking accidents through unit
> confusion.

Would it be clearer to use a non-recommended prefix than a recommended
prefix? Besides, your argument indicates a fundamental confusion. There
is only one SI unit of pressure, the pascal (Pa). That's part of the
beauty and practicality of the system. All the rest that is used to
express pressures relates just the way of expressing the numerical
value. For convenience, we can use multiplier prefixes of _the_ unit if
we like, or a multiplier of the number, consisting of a power of ten.
>
> The preference to use powers of 1000 is just a preference because
> practicality and pragmatism is sometimes more important than an
> arbitrary recommendation. This is a perfect example of where
> pragmatism should (and does) win.

The reason for preferring powers of 1,000, explicitly expressed in
several recommendations and standards, is its practicality, based on
the use of the system as a whole. If you take arbitrary special
aspects, you can always find arguments in favor of using non-SI units
or non-recommended SI expressions - but then you lose all the benefits
of a unified system. Using hPA is a half-hearted "solution" that
combines the trouble of transition (after all, it needs to be
introduced to people who didn't know it, and they need to be reminded,
and some people will inevitably misunderstand or forget) with the
effect of gaining almost nothing. (We _can_ convert millibars to
pascals too.)

--
Yucca, http://www.cs.tut.fi/~jkorpela/

On Sun, 7 Mar 2004 17:42:25 -0000, "Julian Scarfe"
> wrote:

>"Jukka K. Korpela" > wrote in message
. ..
>
>> In practice, using hPa means being just _nominally_ metric, i.e. using
>> actually millibars but under a different name. The odd thing is that
>> the correct kPa would be more practical.
>
>How can you possibly suggest that it would be more "practical" to use kPa?
>There is an installed base of tens of thousands of altimeters in aircraft
>out there that are calibrated in mbar. Describing them as hPa makes it
>clear what the unit is for someone familiar with the SI, without risking
>accidents through unit confusion.
>
>The preference to use powers of 1000 is just a preference because
>practicality and pragmatism is sometimes more important than an arbitrary
>recommendation. This is a perfect example of where pragmatism should (and
>does) win.

Oh, good grief.

Does anybody use feet for altitude?

Do all of the analog instruments show all the digits in those feet?


Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

"Gene Nygaard" > wrote in message
...
> On Sun, 7 Mar 2004 17:42:25 -0000, "Julian Scarfe"
> > wrote:
>
> >"Jukka K. Korpela" > wrote in message
> . ..
> >
> >> In practice, using hPa means being just _nominally_ metric, i.e. using
> >> actually millibars but under a different name. The odd thing is that
> >> the correct kPa would be more practical.
> >
> >How can you possibly suggest that it would be more "practical" to use
kPa?
> >There is an installed base of tens of thousands of altimeters in aircraft
> >out there that are calibrated in mbar. Describing them as hPa makes it
> >clear what the unit is for someone familiar with the SI, without risking
> >accidents through unit confusion.
> >
> >The preference to use powers of 1000 is just a preference because
> >practicality and pragmatism is sometimes more important than an arbitrary
> >recommendation. This is a perfect example of where pragmatism should
(and
> >does) win.
>
> Oh, good grief.
>
> Does anybody use feet for altitude?
>
> Do all of the analog instruments show all the digits in those feet?
>

An just to add to the confusion our aircraft uses pieze for manifold
pressure

"Gene Nygaard" > wrote in message
...
> On Sun, 7 Mar 2004 16:18:10 +0000 (UTC), "Jukka K. Korpela"
> > wrote:
>
> (Pat Norton) wrote:
> >
> >> Do all commercial aircraft that fly in and out of North America have
> >> dual unit altimeters (hPa and inHg)?
> >
> >I don't know about that, but as regards to the metric system, I would
> >like to mention that using hPa is _not_ the recommended way. Although
> >the "h" prefix is formally part of the SI system, it's regarded as
> >unsuitable by many, including NIST.
> >
> >In practice, using hPa means being just _nominally_ metric, i.e. using
> >actually millibars but under a different name. The odd thing is that
> >the correct kPa would be more practical.
>
> Amen.


What about the pieze = 1000 pascals?

On Sun, 7 Mar 2004 20:42:10 -0000, "S Green"
> wrote:

>
>"Gene Nygaard" > wrote in message
...
>> On Sun, 7 Mar 2004 16:18:10 +0000 (UTC), "Jukka K. Korpela"
>> > wrote:
>>
>> (Pat Norton) wrote:
>> >
>> >> Do all commercial aircraft that fly in and out of North America have
>> >> dual unit altimeters (hPa and inHg)?
>> >
>> >I don't know about that, but as regards to the metric system, I would
>> >like to mention that using hPa is _not_ the recommended way. Although
>> >the "h" prefix is formally part of the SI system, it's regarded as
>> >unsuitable by many, including NIST.
>> >
>> >In practice, using hPa means being just _nominally_ metric, i.e. using
>> >actually millibars but under a different name. The odd thing is that
>> >the correct kPa would be more practical.
>>
>> Amen.
>
>
>What about the pieze = 1000 pascals?

The International System of Units is a meter-kilogram-second system of
units.

That mts unit of pressure is no more SI than the cgs unit of pressure,
the barye equal to 0.1 Pa.

Note that bars are so obsolete that they never did fit into any of the
many different coherent systems of units--not only do they not fit in
SI or any other coherent meter-kilogram-second system, but they did
not fit in centimeter-gram-second systems and they did not fit in
meter-ton-second systems.

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

On Sun, 07 Mar 2004 17:33:47 -0500, Cub Driver
> wrote:

>
>>Does anybody use feet for altitude?
>
>Everyone except the Former USSR and China, as near as I can figure.

bravo--you were able to answer the rhetorical question part.

What about the rest of it?

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

>Does anybody use feet for altitude?

Everyone except the Former USSR and China, as near as I can figure.

all the best -- Dan Ford
email: (requires authentication)

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

In misc.metric-system Jukka K. Korpela > wrote:
> "Julian Scarfe" > wrote:
>
>> How can you possibly suggest that it would be more "practical" to
>> use kPa?
>
> Because one digit less is needed, and conversions are easier when
> powers of 1,000 are used as normally.
>

No, you need the same number of digits, and a decimal point in
addition. A pressure difference of 1 hPa corresponds to an altitude
difference of 8 m at sea level. That is just enough precision, but 80
m (corresponding to 1 kPa) would be intolerable. Pilots are usually
required to keep an assigned altitude to within +- 15 m (50 feet).

--
Klaus Wacker
Experimentelle Physik V http://www.physik.uni-dortmund.de/~wacker
Universitaet Dortmund Tel.: +49 231 755 3587
D-44221 Dortmund Fax: +49 231 755 4547

"Jukka K. Korpela" > wrote in message
. ..

> > Describing them as hPa makes it clear what the unit is for someone
> > familiar with the SI, without risking accidents through unit
> > confusion.
>
> Would it be clearer to use a non-recommended prefix than a recommended
> prefix? Besides, your argument indicates a fundamental confusion. There
> is only one SI unit of pressure, the pascal (Pa). That's part of the
> beauty and practicality of the system. All the rest that is used to
> express pressures relates just the way of expressing the numerical
> value. For convenience, we can use multiplier prefixes of _the_ unit if
> we like, or a multiplier of the number, consisting of a power of ten.

I'm not sure where you believe the "confusion" lies. Describing the unit as
hPa rather than mbar makes it clear that the unit is Pa and the prefix,
which is a standard SI prefix, gives the multiplier.

> > The preference to use powers of 1000 is just a preference because
> > practicality and pragmatism is sometimes more important than an
> > arbitrary recommendation. This is a perfect example of where
> > pragmatism should (and does) win.
>
> The reason for preferring powers of 1,000, explicitly expressed in
> several recommendations and standards, is its practicality, based on
> the use of the system as a whole. If you take arbitrary special
> aspects, you can always find arguments in favor of using non-SI units
> or non-recommended SI expressions - but then you lose all the benefits
> of a unified system.

Do you really believe that you lose *all* the benefits of a unified system
by using a prefix described (without deprecation, BTW) in the SI Brochure?

> Using hPA is a half-hearted "solution" that
> combines the trouble of transition

One man's half-hearted solution is another's essential compromise. :-)

Julian Scarfe

> "Julian Scarfe" > wrote:
>
> > How can you possibly suggest that it would be more "practical" to
> > use kPa?

"Jukka K. Korpela" > wrote in message
. ..
>
> Because one digit less is needed, and conversions are easier when
> powers of 1,000 are used as normally.

I forgot to mention in my response, BTW, that the same number of digits *is*
required. Aviation applications require a precision of 100 Pa in measured
pressures. Your choice is between 1013 hPa or 101.3 kPa. By adding the
"daycimal", you simply make it more difficult for pilots to say.

Julian Scarfe

"Gene Nygaard" > wrote in message
...

> >The preference to use powers of 1000 is just a preference because
> >practicality and pragmatism is sometimes more important than an arbitrary
> >recommendation. This is a perfect example of where pragmatism should
(and
> >does) win.
>
> Oh, good grief.
>
> Does anybody use feet for altitude?
>
> Do all of the analog instruments show all the digits in those feet?

Pilots have become accustomed to using feet for altitude. Can you imagine
the confusion that would arise if the unit suddenly shifted by a factor of
10?

"Descend and maintain 300 decafeet"

Any room for confusion there?

We already have trouble enough with pilots screwing up inHg to mbar
conversions. What does an altimeter setting of "nine ninety two" mean?

As a physicist and a pilot, I'd rather live with the inconvenience of using
a hecto prefix for stuff that comes across my desk than risking confusion in
the cockpit. So would ICAO.

Julian Scarfe

"Julian Scarfe" > wrote:

> I forgot to mention in my response, BTW, that the same number of
> digits *is* required.

It depends on the quantities. I was referring to the most common
quantities that people see expressed. When tagging isobars in weather
maps, the trailing zero is just a nuisance. And when more accuracy is
needed, it is natural to accept that fractions might be needed.

> Your choice is between 1013 hPa or
> 101.3 kPa.

You just gave one more reason to favor kPa. The numeric value 1013 is
not in the recommended range, and it raises the question of a thousands
separator, which is language dependent, so that some cultures would use
1 013 (and would need a no-break space to prevent undesired line
breaks, and an en space to avoid too wide a gap, and cannot get both)
while some would use 1'013 or 1.013 or 1,013. Situations where the
quantity will be taken as a thousand times too small would be quite
rare, but the damage could be serious, so why take the risk.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

"Julian Scarfe" > wrote:

> We already have trouble enough with pilots screwing up inHg to mbar
> conversions.

So while you take the trouble, wouldn't it be best to move to something
that lasts, due to being part of a system that is meant to be applied
in all areas of life when expressing physical quantities? It's better
to move directly to the SI system as recommended in general, rather
than first moving, say, to a partly decimal-based variant of the Anglo-
Saxon system, or - to take an example about different quantities -
first move from the use of different gallons to a Unified Gallon, then
to hectoliters, later to what the SI system really recommends.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

>>
The numeric value 1013 is
not in the recommended range, and it raises the question of a thousands
separator, which is language dependent, so that some cultures would use
1 013 (and would need a no-break space to prevent undesired line
breaks, and an en space to avoid too wide a gap, and cannot get both)
while some would use 1'013 or 1.013 or 1,013.
<<

I think this depends on the context of usage. In aviation, I think the
thousands separator would be omitted most of the time, it's primarily a
convenience when you have lots of digits, and four isn't "lots". As for units,
it depends on what you are integrating with. In aviation, you are integrating
with nothing, so you could measure in quattloos for all it matters. It is in
engineering, where many conversions and calculations are taking place, that the
units need to fit into a system and kPa would be preferred.

I live with meters, millimeters, and centimeters just fine. And
(interestingly) in aviation, I live with hundreds of feet and thousands of feet
just fine too. (I flight plan in thousands, such as 4.5K for 4500 feet, but
weather comes in hundreds, as in 45 for a cloud layer at the same alititude. I
kinda wish it were more consistant, but only kinda. Each system has its place.

Jose

--
(for Email, make the obvious changes in my address)

In misc.metric-system Julian Scarfe > wrote:
> Pilots have become accustomed to using feet for altitude. Can you imagine

As a european pilot I would prefer meters.
But how to rearrange separation standards, any ideas?

--
--Peter Hermann(49)0711-685-3611 fax3758
--Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen
--http://www.csv.ica.uni-stuttgart.de/homes/ph/
--Team Ada: "C'mon people let the world begin" (Paul McCartney)

Peter Hermann wrote:
>
> As a european pilot I would prefer meters.
> But how to rearrange separation standards, any ideas?

Use 300 meters for every 1,000'. That's a little less separation, but it wouldn't
be too hard for a pilot to deal with the arithmetic.

George Patterson
Battle, n; A method of untying with the teeth a political knot that would
not yield to the tongue.

"S Green" > writes:
>What about the pieze = 1000 pascals?

http://www.unc.edu/~rowlett/units/dictP.html

pieze (pz)

a metric unit of pressure, part of the "metre-tonne-second" system
sometimes used by European engineers. The pieze is a pressure of
one sthene per square meter, or 1000 newtons per square meter,
or one kilopascal. [...]
The name of the unit comes from the Greek piezein, to press.
The unit, spelled pièze in French, is pronounced "pee-ezz" in English.

Interesting. I had never heard of a metre-tonne-second system
before. Where was it invented and in which fields was it used?

Markus

"G.R. Patterson III" > writes:
>Peter Hermann wrote:
>> As a european pilot I would prefer meters.
>> But how to rearrange separation standards, any ideas?
>
>Use 300 meters for every 1,000'. That's a little less
>separation, but it wouldn't be too hard for a pilot to
>deal with the arithmetic.

If flight levels were named in meters and were all a multiple
of 300 m, this might even add an additional communications-safety
mechanism:

In all valid flight levels, the sum of all digits would
always be divisible by three.

This adds a bit of healthy redundancy to a figure that needs
to be communicated without ambiguity over noisy radio channels.
Getting a single digit wrong would be spotted with >60%
probability. Almost as good as adding a check digit.

Markus

"Markus Kuhn" > wrote in message
...
> "S Green" > writes:
> >What about the pieze = 1000 pascals?
>
> http://www.unc.edu/~rowlett/units/dictP.html
>
> pieze (pz)
>
> a metric unit of pressure, part of the "metre-tonne-second" system
> sometimes used by European engineers. The pieze is a pressure of
> one sthene per square meter, or 1000 newtons per square meter,
> or one kilopascal. [...]
> The name of the unit comes from the Greek piezein, to press.
> The unit, spelled pièze in French, is pronounced "pee-ezz" in English.
>
> Interesting. I had never heard of a metre-tonne-second system
> before. Where was it invented and in which fields was it used?
>
> Markus

Well as I said our aircraft has the manifold pressure in pieze

ie 27 inches = 90 pieze approx

> "Julian Scarfe" > wrote:
>
> > We already have trouble enough with pilots screwing up inHg to mbar
> > conversions.

"Jukka K. Korpela" > wrote in message
. ..
>
> So while you take the trouble, wouldn't it be best to move to something
> that lasts, due to being part of a system that is meant to be applied
> in all areas of life when expressing physical quantities? It's better
> to move directly to the SI system as recommended in general, rather
> than first moving, say, to a partly decimal-based variant of the Anglo-
> Saxon system, or - to take an example about different quantities -
> first move from the use of different gallons to a Unified Gallon, then
> to hectoliters, later to what the SI system really recommends.

The SI is equally happy with hPa or kPa. You've pulled out a standard from
ISO, I think, that is designed to help you make a choice when there is no
reason to do differently. I agree that, if there were no other factors
influencing choice of unit, multiples of 1000 are a good default. But
you've picked on a case where there *are* clearly good reasons -- the size
of the unit, and the equivalence to mbar -- that make hPa a very sensible
and pragmatic choice.

Julian

"Jukka K. Korpela" > wrote in message
. ..
> "Julian Scarfe" > wrote:
>
> > I forgot to mention in my response, BTW, that the same number of
> > digits *is* required.
>
> It depends on the quantities. I was referring to the most common
> quantities that people see expressed. When tagging isobars in weather
> maps, the trailing zero is just a nuisance. And when more accuracy is
> needed, it is natural to accept that fractions might be needed.

But I think you forget where you came into this, Jukka. The thread is
entitled "units of measurement on altimeters". The quantities that need to
be expressed are in the approximate range of 970 to 1040 hPa, with a
precision of 1 hPa. The hPa is the right unit for that job.

> > Your choice is between 1013 hPa or
> > 101.3 kPa.
>
> You just gave one more reason to favor kPa. The numeric value 1013 is
> not in the recommended range, and it raises the question of a thousands
> separator, which is language dependent, so that some cultures would use
> 1 013 (and would need a no-break space to prevent undesired line
> breaks, and an en space to avoid too wide a gap, and cannot get both)
> while some would use 1'013 or 1.013 or 1,013. Situations where the
> quantity will be taken as a thousand times too small would be quite
> rare, but the damage could be serious, so why take the risk.

In context, the need for a thousands separator is not great, is it?

Julian

"Julian Scarfe" > wrote:

> But I think you forget where you came into this, Jukka. The thread
> is entitled "units of measurement on altimeters".

It's part of the very idea of the SI system that a single unit is used
for each physical quantity, in a unified manner, not varying the system
by application, country, or phase of the moon. It is clear that the
system is not always optimal when judged from a narrow perspective of a
specialized field, but if we go that way, we'll end up with expressing
quantities in incompatible ways - there's _always_ at least some reason
to deviate from a system.

The pascal is a very small unit in many areas of everyday life,
technology, and science. This is handled, as usual in the SI system,
using a systematic set of multipliers that correspond to powers of
1000, so that the numeric values can be scaled to a reasonable range,
[0.1, 1000). In some situations it might be, at least due to historical
reasons, marginally more convenient to use 100 or 42 as a multiplier.
But that's not a good approach. (It is true that some additional
multipliers exist in the SI system. But this is due to historical
reasons and discouraged in many standards, and tends to create
confusion because prefixes like h or da are not widely known outside
some specific areas of application, like the hectare.)

> The quantities
> that need to be expressed are in the approximate range of 970 to
> 1040 hPa, with a precision of 1 hPa.

It's against the principles of the SI system to select units according
to the range and precision that you have in some special situation.
We don't invent new units every time we encounter a new situation.
That was the old way.

Quantities in the range 97 kPa to 104 kPa can easily be expressed to
any precision you need or the current technology permits. Surely people
who work with such things can be expected to be able to work with
numbers with a decimal part.

(If it becomes relevant to work with a precision of 50 Pa, would you
insist on inventing a unit that equals 50 Pa, so that you can keep
using integers only? What about 42 Pa?)

> The hPa is the right unit for that job.

No, the hPa is not a unit in the SI system, any more than 100 Pa is.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

>>
It's part of the very idea of the SI system that a single unit is used
for each physical quantity, in a unified manner
<<

This is fine and well while you're sitting in an armchair. But in the real
world there are sometimes compelling reasons to do something different from
the way a machine might handle things. In the case where

1: Not much interfacing with other units is involved
2: Rapid and accurate organic processing of the numbers is essential,
sometimes in adverse conditions.
3: Communications is suboptimal
4: A narrow range of values is involved

I'd say that it makes sense to use whatever units are most convenient in that
case, not whatever would make some world standards body twinkle its toes.
Altimeter settings are such a case.

Jose



--
(for Email, make the obvious changes in my address)

In misc.metric-system Markus Kuhn > wrote:
> If flight levels were named in meters and were all a multiple
> of 300 m, this might even add an additional communications-safety
> mechanism:

> In all valid flight levels, the sum of all digits would
> always be divisible by three.

> This adds a bit of healthy redundancy to a figure that needs
> to be communicated without ambiguity over noisy radio channels.
> Getting a single digit wrong would be spotted with >60%
> probability. Almost as good as adding a check digit.

Subsequently I would like to have a similarly clever idea
how to define SemiCircular Flight Level Rules.
Unfortunately I did not succeed to ignite a contest of ideas
in www.avweb.com via the QuestionOfTheWeek (qotw).
Obviously, U.S.Americans resist international needs.

--
--Peter Hermann(49)0711-685-3611 fax3758
--Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen
--http://www.csv.ica.uni-stuttgart.de/homes/ph/
--Team Ada: "C'mon people let the world begin" (Paul McCartney)

On Mon, 8 Mar 2004 at 20:08:38 in message
>, Julian Scarfe
> wrote:
>
>The SI is equally happy with hPa or kPa. You've pulled out a standard from
>ISO, I think, that is designed to help you make a choice when there is no
>reason to do differently. I agree that, if there were no other factors
>influencing choice of unit, multiples of 1000 are a good default. But
>you've picked on a case where there *are* clearly good reasons -- the size
>of the unit, and the equivalence to mbar -- that make hPa a very sensible
>and pragmatic choice.
>
I know little about this but isn't there a case for making the format of
digits used specific to the function as far as possible?

Call 101 decimal 5; altimeter 1015; Heading 101; altitude 1 thousand 1
hundred for example?

Just a thought.
--
David CL Francis

David CL Francis wrote:
>
> Call 101 decimal 5; altimeter 1015; Heading 101; altitude 1 thousand 1
> hundred for example?

Which means you're right back to hPa, as far as the altimeter goes.

George Patterson
Battle, n; A method of untying with the teeth a political knot that would
not yield to the tongue.

On Mon, 8 Mar 2004 15:50:59 +0000 (UTC), Peter Hermann
> wrote:

>In misc.metric-system Julian Scarfe > wrote:
>> Pilots have become accustomed to using feet for altitude. Can you imagine
>
>As a european pilot I would prefer meters.
>But how to rearrange separation standards, any ideas?

1/3rds of kilometers.

--
Jim Riley