Time and distance to a station
How far and how long to a VOR or NDB from the time a bearing takes to change while you fly square to it, exactly and by the 60-times rule.
Planning and education aid. Not for primary navigation. Full disclaimer
Experimental: not yet fully verified. How results are checked
The station is 11.52 min away, 12 min by the rule.
- Time by the rule
- Distance to station
- Distance by the rule
Provenance
- Computed by
- aviation.ifr.time-to-station 1.0.0, core 0.1.0
- Model
- Flying square to the station, which is abeam when the timing starts, the track flown and the two bearings make a right triangle: from where the timing ends the station is (GS × t) ÷ sin Δ away, so the time is t ÷ sin Δ. The rule, 60 × t ÷ Δ, takes sin Δ ≈ Δ/60 (Instrument Flying Handbook, ch. 9)
- Accuracy
- Exact for a steady wind-free track square to the station; the rule reads about 5% long near 10° and grows with the change
- Notes
- 1 shown with the answer
- Cites
- Federal Aviation Administration, Instrument Flying Handbook, FAA-H-8083-15B
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: Flying square to the station, which is abeam when the timing starts, the track flown and the two bearings make a right triangle: from where the timing ends the station is (GS × t) ÷ sin Δ away, so the time is t ÷ sin Δ. The rule, 60 × t ÷ Δ, takes sin Δ ≈ Δ/60 (Instrument Flying Handbook, ch. 9)
Accuracy: Exact for a steady wind-free track square to the station; the rule reads about 5% long near 10° and grows with the change
Worked example: A 10° change in 2 minutes at 120 kt. Source: Hand check: rule 60 × 2 ÷ 10 = 12 min; exact 2 ÷ sin 10° = 11.52 min. It is golden test vector v001, and every build checks the tool still gives its answer within its tolerance.
You enter
- Bearing change
- 10 deg
- Groundspeed
- 120 kt
- Time for the change
- 2 min
You get
- Time to station
- 11.52 min
- Time by the rule
- 12 min
- Distance to station
- 23.04 NM
- Distance by the rule
- 24 NM
Review: Not yet independently reviewed by a flight instructor (CFI).
Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Checked against: 7 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- Instrument Flying Handbook, FAA-H-8083-15B, Federal Aviation Administration, FAA-H-8083-15B. Chapter 9 (navigation systems: DME slant range, time and distance to a station from a bearing change, DME arcs).
Experimental means this tool has not yet met the stable bar: at least 20 golden vectors, differential tests, and an independent worked example.