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Altitude: Difference between revisions
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some changes in general definitions
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(some changes in general definitions) |
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==General Definitions== | ==General Definitions== | ||
===Height=== | ===Height=== | ||
*Altitude in terms of the distance above a certain point. | *Altitude in terms of the '''distance above a certain point'''. | ||
===True altitude=== | |||
*Altitude in terms of '''[[#Height|height]] above sea level''' ([[AMSL]]). | |||
After setting the [[altimeter]] to [[#QNH|QNH]] the [[#Indicated altitude|indicated altitude]] is close to the true altitude. | |||
===Absolute altitude=== | ===Absolute altitude=== | ||
*Altitude in terms of the | *Altitude in terms of the '''[[#Height|height]] above the ground''' ([[AGL]]) directly below it. | ||
Ground radar and ground warning systems display absolute altitude. | Ground radar and ground warning systems display the absolute altitude. If the [[altimeter]] is set to display zero while being on the airfield, the [[#Indicated altitude|indicated altitude]] will be the absolute altitude as long as the [[#Elevation|elevation]] of the terrain below does not change. | ||
In FlightGear there is a "system" altitude, that altitude is [[AMSL]]. Some will refer to this altitude as [[#Absolute altitude|absolute altitude]], which is theoretically incorrect. | |||
===Elevation=== | ===Elevation=== | ||
The [[#True altitude]] of positions on the ground is referred to as the elevation. In aviation these positions normally are runways or mountain peaks. | The [[#True altitude|true altitude]] of positions on the ground is referred to as the elevation. In aviation these positions normally are runways or mountain peaks. | ||
It is vital to know the elevation of a runway before descending towards it. The best sources for elevation data are: | It is vital to know the elevation of a runway before descending towards it. The best sources for elevation data are: | ||