Air navigation is special kind of general navigation. It is used by pilots in aircraft to know their exact position. That is very important. Because if they get lost, they can for example fly into some dangerous area or hit the mountain. There are generally two types of air navigation depending on weather. When there is a good weather outside, pilots navigate themselves visually with map. But when the weather is bad and they do not see the ground, they use the special radio navigational instruments, radar or the air traffic controller navigates them. First kind of navigation is called VFR (visual flight rules) navigation. The second is IFR (instrument flight rules) navigation. Also we cannot forget the effect of wind on the aircraft in the air.
When the pilot flies VFR flight, he uses his map, compass and he looks on the ground. During the preparation for a flight he chooses big visible points on the map, for example large cities, lakes, hills, rivers, roads or forests. Then when he is in the air, he seeks the chosen points to make sure he is on a good way. The weather must be good enough to let the pilot see the ground. He also cannot fly into clouds, because he can get lost. Pilots also have to look for the other aircraft. It is their responsibility to make sure they do not get too close to other aircraft.
During IFR flight, pilots cannot fly wherever they want. They have to fly only on specified routes. Also the aircraft must have many special devices working with radio waves, GPS or radar. The air routes lead mostly from radio beacon to beacon. Pilot must set the correct frequency of the beacon and fly to it. GPS helps to find exact position of airplane. Each aircraft have special code that is indicated on air traffic controller’s radar screen. Because pilot does not see outside, he has to do what the controller says. And the controller makes sure that the aircraft does not crash.
Effect of wind [change]
The wind is a great problem in navigation. Imagine that pilot sets the plane to fly eastwards (90°). If the wind blows from the north, it will blow the plane to the south. And the aircraft will fly to south-east (135°). So, to fly exactly to the east, pilot must set the plane to north-east. This was just an example. In reality, wind can blow from any direction and at any speed. So pilots must also watch the wind and know how to compensate the effect of the wind on the aircraft.
As aircraft get faster, wind is less and less important. So for a small slow training aircraft, the wind is always changing the aircraft's direction. But for a big airliner which goes much faster, the wind doesn't have an impact apart from take off and landing.