Hi Don, et al., I recall that my father, who was once a pilot, always quoted the air pressure at sea level as "ten-thirteen point two" from his flight training many years ago. Can any of the Canadians familiar with aviation (Marcus?) tell me if hectopascals are/were used in Canada? greg >>> "Hillger, Don" <[EMAIL PROTECTED]> 2001-04-25 08:31:00 >>> Greg, The inch of mercury for surface pressures, used by pilots to calibrate their altimeters, is probably the main reason we don't see a change to millibars or hectopascals (or kilopascals) by the weather services and on TV. Meteorologists certainly don't use inches of mercury. But the inertia is great and I don't know when we'll ever wean pilots of their entrenched system. All upper air temperatures are in Celsius for all applications, but the surface pressure is amazingly still in Fahrenheit! You'd think that one would be more easily changed. There is some move in that direction with the surface observing network now coded in Celsius regardless of whether the temperatures are taken in Fahrenheit, but even some meteorologists refuse to use Celsius for surface temperatures! Don -----Original Message----- From: Gregory Peterson [mailto:[EMAIL PROTECTED]] Sent: Wednesday, 2001 April 25 08:17 To: U.S. Metric Association Subject: [USMA:12464] metric in aviation I have a friend who is currently taking ground-school flight classes here in Saskatchewan. He's just a couple of years younger than me so he also belongs to Canada's first metric generation. He told me that he was quite upset with the whole idea that aviation in Canada (and North America) was still done in Imperial units. He told me that they're still using miles, nautical miles, feet, "and even inches of mercury". Though he did note that one speed gauge listed "mph, knots, and km/h". He also noted that since most of the other people, who happen to be "much older" than he is, were completely comfortable with these units while he had to learn a whole new language. I'm well aware that foot elevation and knot speed are still used in North American aviation, but I was under the impression that Celsius temperature and bar (or hPa) pressure was being used. Could someone update me on the status of American/Canadian aviation units. greg
