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How to Use an E6B Slide Rule

An E6B slide rule is a type of circular manual flight computer that pilots use for flight planning. Specifically, pilots use the E6B to perform time, speed and distance calculations, as well as figure out ground speed, which is the speed an aircraft moves over the ground, and true heading, which is the direction the aircraft's nose points. In addition to flight planning, pilots and aviation enthusiasts use E6Bs for other purposes, such as National Intercollegiate Flying Association competitions or simple multiplication, division, addition and subtraction. E6Bs can be made out of many materials, including paper, plastic and stainless steel.

Things You'll Need

E6B
Winds aloft forecast
Sample airspeeds
Pencil

Instructions

- 1
  Find key figures on the E6B. There are numbers and figures that surround the E6B, but the key ones for flight computing are 60 and the speed arrow. Sixty represents one hour and one minute, and is the key measure of time. The speed arrow is above or in place of 60. Also, keep in mind that all numbers can denote multiples of themselves. For instance, 30 can mean 30, but it can also mean 300 or 3, depending on the context.
- 2
  Learn the back side of the E6B. The back of the E6B allows you to solve problems involving wind. You can figure out your ground speed, wind correction angle and true heading from the back side.
- 3
  Do practice problems using the back of the E6B. Use your winds aloft report and sample airspeeds to figure out your ground speed. Move the hole in the plastic filament, known as a "grommet," to the line that represents your true airspeed. For example, we'll use "100." Move the plastic filament to the wind heading and measure the wind speed up from 100. Use your pencil to mark the wind speed with a dot. For example, if winds are 255 degrees at 20 knots, move the grommet to 100, move the filament to 255 degrees and place a dot on the line marked "120." Next, turn the filament to your true course, which is the actual path your aircraft will travel over the ground. For example, if your true course is 300 degrees, turn the filament to 300. The dot will now show your ground speed as well as your wind correction angle, which is measured in degrees left or right from the center line. In the case of the example, your ground speed should be 85 knots, your true heading should be 292 degrees, and your wind correction angle should be 8 degrees to the left.
- 4
  Do practice problems using the front of the E6B. Using the ground speed that you calculated from the back side, and find the time it will take you to complete your trip. Place the speed needle on your ground speed, find your distance on the outside scale (the nonmovable part), and look below your distance to find the time it takes you to complete your trip. For instance, say you are traveling 50 miles. Using the figures from the example in Step 3, place the speed needle on 85, look to 50 on the outside scale, and read the time on the inside scale.
- 5
  Study the manual. There are many more calculations you can perform on an E6B, and studying the owner's manual is an excellent way to discover other calculations.

Aviation