# NAV 14

## Navigation

Version 1. - May 2006

# A

= 700 divided by 3 multiplied by 11 = 2567 feet

A more complex calculation is usually just a few steps; the system above can often be used for each step. The ‘square’ system is shown for the following calculations.

# Ground speed and fuel use

# To calculate wind speed in knots (ie how many nautical miles in one hour)

(NM)

(minutes)

2

10

Question: You launch at 0830, and at 0840 you fix your position 2NM away. What is the wind speed?

# Set up the square:

# A 60

10 minutes is the time from 0830 to 0840.

# A

= 2 divided by 10 multiplied by 60 = 12 NM (in one hour) ie 12 knots.

To convert this to km/hour, you can set up another square for the next step, using the conversion 1NM = 1.85km.

# (NM)

(km)

1

1.85

12 A

# A

= 12 divided by 1 multiplied by 1.85 = 22.2 km

So a speed of 12 knots will be the same as 22.2 km/hr.

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ABF Pilot Training Manual Part 8