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Old March 7th 04, 08:28 PM
S Green
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"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