Isogonic

Isogonic is a flight computer for pilots who want to understand the number, not just read it.

WEIGHT AND BALANCE, DONE PROPERLY

Most flight computers dropped weight and balance or never had it. Isogonic plots the envelope, marks your take-off and landing points, and tracks the CG along the whole fuel burn between them.

Burning fuel moves the CG along a curve, not a straight line, so checking only the endpoints can miss an excursion mid-flight. Isogonic checks the entire path, which is what the ACS asks for: within limits "during all phases of flight".

It reads both envelope conventions, CG against weight and moment against weight, because converting by hand is where mistakes get made. Pounds and inches, or kilograms and millimetres.

SHOW THE WORK

Tap any answer and Isogonic unfolds it: every input, every intermediate value, the formula, and the rule of thumb you can say out loud, with the exact error that shortcut carries. Examiners ask how the number was derived. So does anyone who wants to learn it.

HOLDING, AS THE GROUND SEES IT

Textbooks draw the hold as a tidy racetrack. That is the air path. With any wind in it, the ground track is a different, lopsided shape. That gap is why holds are hard.

Isogonic draws both, overlaid, with the entry, the tripled outbound drift correction and the leg timing that follow. Entry comes from your heading, never your ground track, and it flags the five-degree band where the FAA accepts either answer.

CORRECT, AND CHECKABLE

Every atmospheric constant is derived from first principles, not copied from a published decimal, because the rounded forms in circulation disagree. At exact ISA conditions Isogonic returns exactly zero density altitude.

True airspeed comes from calibrated airspeed with compressibility, so it stays honest in the flight levels. Density altitude accounts for humidity if you give it a dew point, another 100 to 250 feet on a hot damp day.

BUILT FOR A COCKPIT

- Its own keypad, never the system keyboard
- Big keys, haptics, and a key fires on release, so turbulence does not
- Portrait and landscape both first class, because polarised sunglasses black out one of them
- A night mode that goes deeper than Dark, to protect night vision
- Results pinned above the inputs
- The keypad folds away, and returns the moment you touch a field
- Units set per quantity: knots and feet in the air, litres and kilograms on the ground

WHAT IS INSIDE

Wind triangle, forwards and backwards. Runway crosswind and headwind, with a true/magnetic switch. Pressure altitude. Density altitude with humidity. ISA deviation. True airspeed and Mach with compressibility. Weight and balance with plotted envelopes. Holding entries and wind correction. Fuel with regulatory reserve. Descent planning, top of descent, gradient in ft/NM and per cent. Twelve live unit conversions. Two cockpit timers. Time, speed, distance. Point of no return. Equal time point. Rate and radius of turn. Glide. Cloud base. Freezing level. Cold