To be able to fly an aircraft from one point or airport to another without getting lost, the pilot has a number of methods available to navigate the route. Pilotage and dead reckoning are the two most basic methods that can be used and in addition to that we can use radio navigation (ground and satellite based) and other sophisticated systems bringing us to our destination.
This page will start with the most basic ones and it shows that these still remain to be most often used forms of navigation by general aviation pilots flying VFR. Anyone can use a GPS handheld device but flying by compass, map and clock to your destination has a much greater satisfaction factor. So on this page we are going to lay the groundwork for that.
In the days when radio navigation systems were not so prevalent, pilots used to fly and find their way by following roads, rivers, railroads and other prominent landmarks. This is called pilotage. Some even call this jokingly IFR: I Follow Roads. And even in this day and age of multifunction personal devices (iPad, Tablets and EFIS) it still a preferred form of navigation by some pilots (grey hair or not).
To navigate successfully using this method you will need a current aeronautical map of the area of interest and then select an altitude that will allow you to locate symbols depicted on the map on the ground below you. Flying too high (above 3000 feet AGL, depending on prevailing weather) will make ground features too small to recognize. Flying too low could result in colliding with tall structures or even hills (controlled flight into terrain, CFIT).
The advantage of this method is that you will not need any special instruments in the aircraft. But on the other hand, navigating over areas where few landmarks are present is difficult to perform, and flying a direct course sometimes even impractical. Even more so when visibility is reduced by weather, fog or smoke, making genuine pilotage a real challenge.
There are no rules for selecting checkpoints as long as they can be positively identified and verified they can be used. For example when verifying a town, do not depend on the water tower but try to select at least two other features (rivers, railroad etc) specific for that town or city.
When selecting a route, try to fly in a straight line as much as possible and pick your landmarks on both sides of your desired track. This will reduce your flight time somewhat and results in more accurate timing and fuel calculations, and possibly not getting lost at all.
This navigation technique is based on mathematical calculations of time, speed, distance and direction. And to predict the movement of your aircraft you will need the following items: TAS, course, wind speed and direction. From these variables you obtain the wind correction angle to deduce groundspeed and heading required to navigate.
This is an important tool as you will determine true course and distance with it when drawing a line on your chart (check your manual for specific instructions for your plotter). Next you will need current weather for the route: important items to look for are air pressure and temperature, dew point, winds aloft and cloud bases. Armed with this information you are able to deduce all the variables we mentioned earlier.
As we fly using compass headings we need some extra information which can be obtained from the charts. This is the deviation error the compass has with regard to true north used on the charts. Our compass points to magnetic north and not to the real north pole so we need to correct for this error, more information on compass errors here.
At this point we have all information required to fill out our navigation log for use in the aircraft while enroute to our destination. You will find detailed information on filling out navigation logs here.
There is a small but easy rule of thumb that lets you get back on your desired route should you discover that you are off track. This formula uses the 1 in 60 rule which says that when steering 1° off track you will be 1 mile off track after flying 60 miles (see image). And in our example that would be 2° (and 2 miles) at point X.
Let us assume that you have flown 60 miles along your route (A to B) of 90 miles and you discover that you are 2 miles to the left of your intended track. The track error (TE) is therefore TE = (60 / Distance Flown ) × Track Distance. In our example the track error is: (60 / 60) × 2 = 2°. A heading correction of 2° to the right and you will fly parallel to your desired track.
But to get to our destination we need a closing angle (CA): CA = (60 / Distance To Go) × Track Distance or (60 / 30) × 2 = 4°. Thus here we need to steer another 4° to the right to arrive over our destination after 30 miles.
We can see that the total correction after 60 miles and with a 2 mile track error would then be a 6° course change to the right.
As you can see, pilotage and dead reckoning form the basic navigation skills every VFR pilot should poses and keep polished. By always preparing your flight in this way and only employing more modern navigation methods as a backup and verification tool you will never find yourself lost should technology fail on you some day.Written by EAI.