PPL NAV cockpit calculations

[hugh flung_dung]

Ditch the gadgets and learn the following:

1. maximum drift (MD) angle = windspeed x 60/TAS. MD is calculated during initial planning and written on chart or PLOG.
2. turn to track, use the DI to estimate the angle between the wind and track and turn towards the wind by 1/6th of MD for every 10 degrees (use full MD if angle 60 degrees or greater)
3. use the DI to estimate the head/tail wind by taking 1/6th of the windspeed for every 10 degrees from the beam (use full WS if angle 60 degrees or greater). Estimate groundspeed.
4. you will fly a distance equal to 1/10th of your groundspeed in 6 minutes so it's easy to estimate leg time

This completes all the necessary nav calcs. In the air it takes about 30 seconds to do and needs no distracting gadgets.
There's an explanation here of how to use the DI to estimate proportions.

To correct to track use either of these techniques to get you back close to track:

1. estimate the error angle, turn towards track by double the error and fly for the same time it took to get to the point where you started the correction.
2. Before flight calculate a Standard Closing Angle for your intended TAS: SCA= 3600/TAS. In flight, if you are off track by y miles then simply turn toards track by your SCA and fly for y minutes.

Now decide why you were off track and act accordingly.

These techniques really are very simple once they're in your head, but they sound complicated when reading from the page. They work.

HFD