The calculator side
The front of an E6B is a circular slide rule. Two logarithmic scales, one on the fixed base and one on the rotating disc, turn multiplication and division into lining up numbers:
- Outer scale (fixed): distance, fuel, true airspeed, or any value being multiplied.
- Inner scale (turns): time in minutes, calibrated airspeed, or the divisor.
- RATE index: the magenta triangle at 60 on the inner scale, one hour. Put it under a speed or burn rate and every time on the inner scale sits under the distance or fuel for that time.
- SEC index at 36: 3,600 seconds, for problems timed in seconds.
- Hours ring inside the minutes scale: the same times written as hours and minutes.
- NAUT, STAT and KM arrows: put a distance under one and read it under the others.
- Altitude windows: pressure altitude over temperature for true airspeed, with density altitude read from the same setting.
The wheel has no decimal point. 88 on the scale can mean 8.8, 88 or 880; you place the decimal by a rough estimate, and the guided steps show that reasoning each time.
Guided problems
Choose a problem, enter your numbers and press Solve on the wheel. The disc turns, the cursor moves to the answer and the step list explains what just happened:
| Problem | Setting | Read |
|---|---|---|
| Time en route | RATE index under ground speed | Time below the distance |
| Distance flown | RATE index under ground speed | Distance above the time |
| Ground speed | Time under distance | Speed above the RATE index |
| Fuel used | RATE index under fuel burn | Fuel above the time |
| Fuel burn rate | Time under fuel used | Burn above the RATE index |
| True airspeed | Pressure altitude over temperature | True airspeed above calibrated airspeed |
| Density altitude | Pressure altitude over temperature | Density altitude at its index |
| Unit conversion | Distance under NAUT | Statute miles under STAT, kilometers under KM |
| Multiply, divide | 10 index or divisor | Product or quotient on the outer scale |
The answer also shows the calculator's exact value, so you can see how close a wheel reading gets.
The wind side
The back of an E6B solves the wind triangle with a pencil dot. The simulator's wind side has a transparent compass rose that turns over a sliding grid of speed arcs and drift lines. The guided wind problem walks through the classic method:
- Turn the rose until the wind direction is under the TRUE INDEX.
- Set the grommet on a convenient speed arc and mark the wind dot straight up from it by the wind speed.
- Turn the rose until the true course is under the TRUE INDEX.
- Slide the grid until the dot sits on the true airspeed arc.
- Read the ground speed under the grommet and the wind correction angle on the drift line through the dot.
With the default problem (true course 090°, 120 knots, wind from 045° at 40 knots) the wheel ends at 88 knots and 14° left, a true heading of 076°. That is the answer the wind correction angle calculator and the Pilot's Handbook give.
Free play
Everything can also be moved by hand: drag the disc, the cursor, the rose or the grid, or focus one and use the arrow keys. Tap the rose to mark your own wind dot. The readout above the problem list always says what sits under the cursor and the RATE index, or which arcs the grommet and the dot are on.
New to the E6B? The step-by-step guide explains each problem with worked numbers, and the flight computer guide covers metal versus electronic models for the knowledge test.
Solve a time-speed-distance problem on the E6B simulator
- On the calculator side, choose Time en route in the guided problems and enter the distance and ground speed.
- Press Solve on the wheel. The disc turns until the RATE index sits under the ground speed on the outer scale.
- The cursor moves to the distance on the outer scale; read the time in minutes below it on the inner scale, or as hours and minutes on the hours ring.
- Place the decimal point by estimate, then compare with the answer the step list gives.
Questions pilots ask
Is this E6B simulator accurate?
Its scales are drawn from the same logarithms a metal E6B uses, and automated tests check that every guided reading equals the site's calculators. On screen you read it by eye, just like a real wheel, to about 1 percent.
Can I use it to practice for the FAA knowledge test?
Yes, that is what it is for: the guided problems show each step and the answer. On test day bring a mechanical E6B or an electronic flight computer; phones are not allowed in the testing area.
How do I turn the disc precisely?
Drag it, or click it and use the arrow keys: each press turns a quarter of a degree, and Shift turns five degrees. Set the disc yourself also lets you type the two values you want lined up.
What do the altitude windows do?
The upper-left window sets pressure altitude against temperature for true airspeed; the density-altitude window on the right reads density altitude from the same setting. They work like the windows on a mechanical E6B, using the density method.