If you are flying from A to B and find you have drifted off your desired track, the 1-in-60 rule can be used to calculate:
We can then find how many degrees we need to turn to fly direct to our destination.
The 1 in 60 rule says:
If you have flown 60nm and are 1nm off-track, your track error angle is 1°.
If you were to turn 1° back towards your destination, you would fly parallel to your desired track.
In this example, we have another 60nm to fly to our destination. We use the 1 in 60 rule again to get the correction angle.
In this case, we are halfway along our track so the two angles are the same. We need to turn 2° left to arrive overhead our destination (point B).
What if the distance is not 60nm? Let’s have a look at this with an exam style question on the 1 in 60 rule:
You are on a navigation flight and have flown 30nm from your point of departure. A visual position fix indicates that you are 3nm right of track. The total planned distance for the flight was 50nm. What change of heading should you make to arrive overhead your destination?
Always draw a diagram to help you visualise the situation!
1 We are 3nm right of track after flying 30nm. If we were to continue flying 60nm, we would end up 6nm right of track. So our track error angle is 6°
If we turned 6° to the left, we would fly parallel to our desired track.
2 The whole flight was 50nm so we have 20nm to go to the destination (50nm – 30nm = 20nm). As our distance to fly is one-third of 60, the correction angle we need is three times our distance off track.
So to correct the 3nm off track, we need a correction angle of 9° (3 x 3 = 9).
3 To arrive overhead our destination, we need to combine the track error angle and the correction angle.
6° + 9° = 15°
We must turn 15° left to arrive overhead our destination