5 / 20
On a Polar Stereographic chart, the initial great circle course from 70°N, 060°W to 70°N, 060°E is approximately…
• A
150° T
• B
210° T
• C
030° T
• D
330° T

Refer to figure.

Draw a diagram:

1. Draw the circle with 70ºN latitude

2. Mark the three local meridians

A – 060ºW
B – 060ºE
Greenwich Meridian (000ºE/W) – DATUM meridian

1. Draw a straight line between A – B, representing the GCT

2. A and B are of the same latitude => Rhumb line track is 090ºT

The difference between true track at A and B = conversion angle which equals ½ Convergency

Note: on a polar stereographic chart, convergency is always the same to the change in longitude

Convergency = change of longitude
Convergency = 120º
Conversion Angle = ½ x 120º = 60º

At A, GCT < RLT
Therefore, GCT = RLT – conversion angle
GCT = 090ºT – 060º = 030ºT

Your Notes (not visible to others)

This question has appeared on the real examination, you can find the related countries below.

• United Kingdom
• Poland
• Austro Control