Time, Distance, Speed Problems

INSTRUMENT FLIGHT RULES WORKBOOK

CHAPTER FIVE

502. THE COMPUTATION SIDE OF THE CR-2 COMPUTER

Before discussing the required procedures for various calculations, one needs to understand this

chapter is designed as a refresher course only. Based on the skills you learned during Aviation

Indoctrination, these problems are simple in comparison. If you require more detailed

information, refer to your AI pubs, CR-2 Instruction Manual, or consult an academic instructor.

Before attempting to solve the following problems, familiarize yourself with the makeup of the

front side of the CR-2 computer. This computer is nothing more than a circular slide rule

designed for aviation.

503. TIME, DISTANCE, SPEED PROBLEMS

You must learn to use the CR computer to rapidly and accurately solve problems associated with

time, distance, and speed.

When working with time, distance, and speed information, by knowing any two of these you can

find the third by using the index. The index represents 60 minutes (on the inner scale); thus, you

could say that the index is used as a basis for what is happening per hour. Match any distance

with the corresponding time (for a portion of your flight) and every other time and distance will

match correctly around the dial.

A time, distance, and speed problem is set up using the following ratio:

rate per hour

distance

time

(index)

DIS

Figure 5-1 Time, Distance, and Speed

5-2 CR-2 COMPUTER