Mountains are not shown with heights in hPa.
> [Original Message] > From: John S. Ward <[EMAIL PROTECTED]> > To: U.S. Metric Association <[EMAIL PROTECTED]> > Date: 15/12/03 22:04:52 > Subject: [USMA:27857] RE: Airplane altitudes > > Carleton, > > It seems like the killer solution to metricating flight altitudes would be to > directly use pressure in hPa. It's simply wrong to call it "feet" or > "meters" if airplanes really are flying on surfaces of constant pressure. > Any idea why this isn't standard practice? Have you seen this discussed > before in the pilot circles? > > John > > On Monday 15 December 2003 04:00, Carleton MacDonald wrote: > > Feet and kPa are not directly related. > > > > What it does mean is that an altimeter, set to standard pressure (1013.2), > > will read the altitude indicated, if the outside pressure at that altitude > > is the amount given. > > > > And the main reason for the common setting at and above FL 180 is to make > > sure everyone up there is using the same standard, so they are separated > > with relationship to each other. > > > > Carleton > > Former flight instructor > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf > > Of Terry Simpson > > Sent: Sunday, December 14, 2003 20:52 > > To: U.S. Metric Association > > Subject: [USMA:27849] RE: Airplane altitudes > > > > >can we know what range of altitude the plane is actually at? > > > > Near Norway right now, the pressure is 968 hPa. A pilot with an altimeter > > set to the standard 1013 hPa therefore has a pressure error of 45 hPa. > > There are about 10 m (30 ft) per 1 hPa. It will read '33 000 ft' when it is > > around 31 500 ft. > > > > Over Portugal right now, the pressure 1033 hPa. A pilot with an altimeter > > set to the standard 1013 hPa therefore has a pressure error of 20 hPa. It > > will read '33 000 ft' when it is around 33 700 ft. > > > > >How did you come up with 33 000 ft = 26.2 kPa? > > > > http://mtp.jpl.nasa.gov/notes/altitude/altitude.html --- Michael Payne --- [EMAIL PROTECTED] --- EarthLink: The #1 provider of the Real Internet.
