About the calculations
Simple tools. Transparent methods. Practical limits.
The method behind the numbers
Wind components use basic vector trigonometry. A positive lateral component means wind from the right; a negative along-runway component means tailwind. Headings wrap through north.
Solving the wind triangle
Ground speed and wind correction solve for a desired course. The heading offsets into wind; forward ground speed combines the remaining forward airspeed and the wind component. Impossible courses are rejected.
True airspeed and the atmosphere
True airspeed uses equivalent airspeed divided by the square root of density ratio. Density comes from a standard tropospheric pressure model and the entered outside temperature. The supported range is −2,000 to 36,000 ft; dry air is assumed. CAS may approximate EAS only at low Mach.
Fuel planning
Fuel required combines planned flight time at the entered hourly burn, reserve time at that rate and a fixed start/taxi allowance. Mass and volume units are kept separate.
Route points
Point of no return balances outbound and return flight time against endurance after reserve. Point of equal time balances time back against time onward. Both use entered directional ground speeds and a simplified constant-speed route.
Pressure and density altitude
The altitude calculations page estimates QFE and pressure altitude from QNH and airfield elevation using a standard-atmosphere altimeter model. Density altitude uses the common approximation of 120 ft per °C difference from ISA temperature at pressure altitude. It excludes humidity and is for planning only.
Verification and references
The calculation library has automated tests covering cardinal winds, heading wrap-around, gust validation, unit equivalence, rounding, wind-triangle solutions, altitude estimates and URL restoration. Automated tests do not constitute certification or an independent aviation review.
For aviation principles and operational context, consult the FAA handbooks and manuals and FAA safety-of-flight guidance. Use your approved aircraft documentation for decisions.
Consistent units
Speeds are normalized through knots. One knot equals 1.852 km/h or approximately 1.150779448 mph. Display values round to one decimal; formulas retain precision.