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Name: katie
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1995


Question:
How can a pilot tell where he has going if all he can see is clouds?



Replies:
Hi Katie:

You have asked an interesting question. There are several ways that a pilot can tell which way he/she is going. First of all, he could use a compass, which uses the magnetic field of the earth to determine direction. However, the compass is not really used by pilots now days, besides it would be difficult to use a compass if you were flying over the north or south poles (basically it would be useless). Pilots now days use satellites that orbit the earth and devices called geographical positioning systems (GPS). These GPS devices will use three different satellites to determine position with a technique called triangulation. The satellites emit a signal that the GPS can receive to determine its position relative to the satellite. If at least two satellites are used and sometimes even three are used, the position of the aircraft can be determined relative to the earth. The output from the GPS will be a coordinate in longitude and latitude on the earth's surface. These GPS systems are also used to determine the plane's speed because it also contains a clock. If you know the position change and the elapsed time then you can calculate the speed by dividing the distance covered by the elapsed time.

david r munoz


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