Avionics
Basic

One-in-Sixty Rule

Rule-of-thumb linking a lateral track error to an angular deviation: 1 nm off after 60 nm is about 1° of error.

Formula

θ=60×doffdflown\theta = \dfrac{60 \times d_{off}}{d_{flown}}

Variables

θTrack error (degrees)
d_offDistance off track (nm)
d_flownDistance flown (nm)

Example

2 nm off after 30 nm: θ = 60×2÷30 = 4°

Did You Know?

Course-deviation indicators for VOR and GPS are built around this rule — each dot of needle deflection represents a fixed angular error from the desired track.

navigationtrack errorone in sixtycdi

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