CR-3 Air Navigation Computer (Calculator Side)
Information Sheet No. 4.3.1I
To be proficient at air navigation, all aviators must possess some basic mathematical skills.
Using specialized, handheld electronic calculators could solve all problems associated with
air navigation; however, these problems can be solved quickly and accurately with the CR-
3 air navigation computer. The advantages of the CR-3 over electronic calculators are
twofold: reliability and cost.
CARE AND COMPONENTS OF CR-3
The plastic CR-3 computer is fragile and must be cared for properly by observing the
Do not leave the computer in direct sunlight such as on the dashboard of a car or a
windowsill. Heat will cause the computer to warp.
Use only a soft lead pencil or a felt tip pen on the wind side of the computer.
Keep the computer clean - avoid getting dirt between the discs of the computer.
Figure 4.3-1 shows the major components of the calculator side of the CR-3. The warrior-
aviator must become familiar with this computer in order to be proficient at air navigation.
The CR-3 is a two-sided disk with a circular slide rule, or calculator, on the front and a
graphic display for wind calculations on the back.