Cold Wx ops...
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Join Date: Jan 2007
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Cold Wx ops...
Hi, on the jeppesen intro ( ATC section pag 254) is reported the table about the correction for the app minima on cold Wx and the reported table is reffered on sea level. Jeppsen also say that in this way the values are conservative in case we should land on higher airport...
My question is....the temperature error on the altimiter is not greater at higher airport than at sea level?
Thanks
My question is....the temperature error on the altimiter is not greater at higher airport than at sea level?
Thanks
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Join Date: Apr 2002
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The density gradient (change of density with altitude) of atmospheric air is greater near sea level than at altitude. Therefore, a proportionate change to density (lower temperature) will have the greatest effect at lower altitudes.
Hope this helps
Hope this helps
Join Date: Nov 2000
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QNH is the actual airfield pressure, reduced to sea level using ISA conditions, so your altimeter will indicate the correct reading when on the ground. The temperature error correction is for the increased density of the air between the airfield and your aircraft, and so is relative to your height above the airfield, whatever its elevation happens to be.