The 1 in 60 rule is the single most useful piece of mental maths in EASA ATPL General Navigation. Learn it once and it pays off in Gen Nav, Flight Planning, Radio Navigation and even your instrument approaches.
Here is what it is, why it works, and how to apply it fast under exam pressure.
If you travel 60 nautical miles and end up 1 NM off your intended track, your track error is almost exactly 1°. It is a small-angle approximation: at 60 NM, 1 NM subtends roughly one degree.
That single relationship scales. Off by 2 NM after 60 NM? About 2° of error. The rule turns a geometry problem into arithmetic you can do in your head.
To correct your heading back onto track you work with two angles:
Turning by the track error alone only makes you parallel the original track. To actually regain it, add the closing angle.
You have flown 30 NM along a 90 NM leg and find yourself 2 NM right of track.
After 20 NM you are 1 NM left of track. Track error = (1 ÷ 20) × 60 = 3°. Turn 3° right to parallel the track, or more to regain it. No plotter, no CRP-5 — just arithmetic.
The same 1-in-60 logic underpins several other exam favourites:
You will meet the 1 in 60 rule directly in General Navigation track-correction questions, and indirectly in Flight Planning (descent profiles), Radio Navigation (deviation at range) and Performance (climb and descent gradients). Examiners like it because it rewards the candidate who can reason quickly rather than reach for a calculator.
Practise it until the arithmetic is automatic. Under time pressure, a five-second mental estimate frees your minutes for the questions that genuinely need them.
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It is a small-angle approximation stating that an aircraft 1 NM off track after 60 NM has a track error of about 1°. It lets pilots calculate heading corrections quickly without instruments.
Track error in degrees = (distance off track ÷ distance gone) × 60. To regain track by your destination, add the closing angle: (distance off track ÷ distance to go) × 60.
It is very accurate for angles up to about 20–25°. Beyond that the small-angle assumption weakens and the calculated angle increasingly understates the true angle.
Mainly in General Navigation for track correction, and in Flight Planning, Radio Navigation and Performance for descent gradients and deviation estimates.
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