> From: Paul Trusten, R.Ph. [mailto:[EMAIL PROTECTED] >the idea of the U.S. being the only non-metric country >doesn't jibe with a world of pilots and air traffic controllers >still using feet.
As with many of these issues, it is not possible to parse a statement like "the world of aviation is non-metric". It is generally non-metric for some things and generally metric for others. It is true that non-metric is default for certain key units (vertical length, climb rates, navigation lengths, horizontal speed). I know that km (and even m/s) are common (but not universal) in gliding. However, metric is the default for other units: Temperature Weight Volume Horizontal separation Airport dimensions Visibility Precipitation (rain, snow) Pressure The US and Canada are the only major countries that use non-metric units for the above as far as I know. The two units 'statute mile' and 'inch of mercury' are not used elsewhere. Britain and Ireland changed to metric units for the above applications a few decades ago. The situation is not static in the US and Canada, they switched from Fahrenheit to Celsius a few years ago. Thus we could now be in a situation where the whole world of aviation uses the same unit of temperature.
