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/homep...d/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/