VFR Flight Planner Calculator

This calculator runs the classic VFR time/speed/distance/wind problem for a single leg. It first finds the angle between the wind's direction and your intended true course, then splits the reported wind into a headwind component (wind speed times the cosine of that angle) and a crosswind component (wind speed times the sine), the same trigonometric breakdown every private pilot learns for runway wind analysis. The wind correction angle — how many degrees you must crab into the wind to track your course — comes from the arcsine of crosswind divided by true airspeed, and that angle is added to or subtracted from your course to produce the heading to fly, depending on which side the wind is pushing from.

Groundspeed here is calculated as a simplified true-airspeed-minus-headwind figure rather than the full vector triangle (which would use the Pythagorean relationship between TAS, crosswind, and groundspeed); for typical light-aircraft wind angles this simplification is close enough for flight planning, but it will run a little optimistic in strong, highly-quartering winds. Flight time, enroute fuel, and reserve fuel follow directly from groundspeed and your entered burn rate, with the VFR reserve defaulting to the FAA's 30-minute day minimum set by 14 CFR 91.151 (bump it to 45 for the regulation's night VFR minimum). Because no magnetic variation input exists, the "heading to fly" output is a true heading — you'll still need to apply your local variation and any known compass deviation before flying it.