How do I use this calculator?
Select one of the three operations. For a rejoin correction, enter distance progressed along the planned track, lateral offset, distance remaining to the rejoin point, and the side you are off track. The result adds the track-error and closing-angle estimates.
To estimate off-track distance, enter an along-track distance and an angle. To estimate track-error angle, enter an along-track distance and lateral offset. Choose units beside each distance; the calculator converts them consistently.
Select Calculate to run the estimate. Calculation details explains the formula and exact planar comparison. Reset clears this calculator’s inputs and saved result.
Calculate aviation track error, closing angle, total heading correction, or off-track distance with the 1-in-60 rule and an exact-trigonometry comparison.
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1 In 60 Rule Formula
The following formula is used to calculate the track error using the 1 in 60 rule.
Variables:
- E is the track error (nautical miles)
- D is distance progressed along the planned track (nautical miles)
- θ is the angle of deviation (degrees)
To calculate the track error, multiply the along-track distance by the angle of deviation. Then divide the result by 60. This will give the track error in nautical miles.
This is a small-angle approximation, not an exact navigation solution. For the tangent comparison, D is the adjacent, along-track leg and E is the perpendicular cross-track offset. If distance means the slanted straight ground path instead, the exact relationship uses sine. The calculator’s rejoin correction assumes a simple track model and does not account for changing wind or operational constraints.
What is a 1 In 60 Rule?
The 1 in 60 rule is a rule of thumb in aviation where a one-degree error in the flight path will produce a track error of approximately 1 nautical mile after 60 nautical miles of flight. It is used for quick mental calculations for navigation and error correction, particularly in visual flight conditions. The rule is based on the small-angle approximation of trigonometry.
How to Calculate 1 In 60 Rule?
The following steps outline how to calculate the 1 In 60 Rule.
- First, determine the distance progressed along the planned track (D) in nautical miles.
- Next, determine the angle of deviation (θ) in degrees.
- Next, use the formula E = (D * θ) / 60 to calculate the track error (E) in nautical miles.
- Finally, calculate the 1 In 60 Rule.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Along-track distance (D) = 120 nautical miles
Angle of deviation (θ) = 2 degrees. The estimate is E = 120 × 2 / 60 = 4 nautical miles. The exact planar tangent comparison is approximately 4.1905 nautical miles.
