Worked Examples — 1-in-60 Rule

The concept lesson on the 1-in-60 rule is in Z/S/D + 1-in-60 Rule. Here follow four worked exercises from simple to complex.

Exercise 1: Compute the track error

Plan: 100 NM leg from waypoint A to waypoint B, planned true track 090°. Actual: after 25 NM you notice you are 2 NM left of the plan track.

Question: how big is the track error (TE)?

Solution: TE = (Do × 60) / Df = (2 × 60) / 25 = 120/25 = 4.8°.

Since you are left of plan, you have drifted 4.8° too far left → wind blows stronger from the right than planned.

Exercise 2: Closing angle and total correction

Same situation: 100 NM leg, 25 NM flown, 2 NM left off-track.

Question: what heading change is needed to hit waypoint B exactly?

Solution:

Remaining distance Dr = 100 − 25 = 75 NM.
Closing angle CA = (Do × 60) / Dr = (2 × 60) / 75 = 120/75 = 1.6°.
Track error TE = 4.8° (from Exercise 1).
Total correction = TE + CA = 4.8° + 1.6° = 6.4°.

Since you were left of plan: correct heading 6.4° right. If old heading was 095° (with +5° WCA), new heading = 101°.

Exercise 3: Correction with multiple legs

Plan: leg of 90 NM, planned heading 180°. After 30 NM: 1.5 NM right off-track. Correction made. After another 30 NM (total 60 NM): 0.5 NM right off-track (instead of 0).

Question: was the first correction right?

Solution Step 1: first correction at 30 NM.

TE = (1.5 × 60) / 30 = 3°.
Dr (then) = 90 − 30 = 60 NM.
CA = (1.5 × 60) / 60 = 1.5°.
Total correction = 3 + 1.5 = 4.5° left.

Step 2: after another 30 NM, residual off-track 0.5 NM right.

Correction was not complete — 0.5 NM right remained.
New TE calculation over the latest 30 NM (excluding first correction period) becomes complex; in practice you do a residual correction.
Remaining distance = 30 NM.
CA = (0.5 × 60) / 30 = 1° additional left.

→ Lesson: first correction was nearly right (about 90 % effective). 1° residual left correction suffices.

Exercise 4: Track deviation on approach

Approach to runway 24 (240° magnetic), 6 NM from touchdown. Pilot notes: 0.2 NM left of the localiser.

Question: what correction?

Solution:

Df on approach does not change directly — we use "off-track in NM × 60 / remaining distance" as pure CA.
CA = (0.2 × 60) / 6 = 2° right.

→ Heading 2° right → 242°. Over 6 NM this closes the 0.2 NM offset.

Take-away

1-in-60 is fast, mentally computable, standard in the cockpit.
More accurate than a "by eye" rule of thumb, less than E6B or GPS.
Double rule to remember: with short remaining distances, double the correction (CA grows steeply).