Navigation Theory

Question 1

Notes

Answer 1

• You should “fix” the aircraft’s position every 10-15mins.

Question 2

What is deduced reckoning?

Answer 2

Deduced reckoning is the primary means of visual cross-country navigation. It is commonly known as dead reckoning (DR). It is based on:
- Starting at a known position (called a fix)
- Measuring the track and distance on a chart to the next point chosen along the desired track
- Applying the best estimate of wind velocity available to determine: the heading to steer to achieve the desired track; and the groundspeed to find the estimated time of arrival over that next point.

Question 3

What is a fix?

Answer 3

A fix is the geographical position of an aircraft at a specific time, determined by visual reference to the surface of the earth, or by radio navigation equipment.

Question 4

What is a pinpoint?

Answer 4

A pinpoint is the ground position of an aircraft at a specific time determined by direct observation of the ground (not by radio navigation equipment).

Question 5

What is the track made good (TMG)?

Answer 5

The Track Made Good (TMG) is the actual track the aircraft is making over the ground.

Question 6

What is the track error (TE)?

Answer 6

The difference between the desired track and the actual TMG is known as the track error (TE).

Question 7

What’s the CA?

Answer 7

The angle at which you want to close on your required track is known as the closing angle.

Question 8

What is the required track (TR)?

Answer 8

The angle at which you want to be following.

Question 9

What’s a position line?

Answer 9

A position line is an extended straight line joining two points, somewhere along which the aeroplane was located at a particular time.

Question 10

Which squawk code should be set in the event of being lost?

Answer 10

0030, FIR lost

Question 11

What’s the Inverse-Ratio method?

Answer 11

The Inverse-Ratio method is a means of correcting the required track after realizing your off-course.

• At 1/2 way point, alter heading by CA x 2
• At 1/3 way point, alter heading by CA x 3
• At 1/4 way point, alter heading by CA x 4
• At 1/5 way point, alter heading by CA x 5

Question 12

What’s the 1-in-60 rule?

Answer 12

The 1-in-60 rule is based on the fact that:
1nm subtends an angle of 1° at a distance of 60nm.
This statement can be extended to say that:
5nm subtends an angle of 5° at 60nm
10nm subtends an angle of 10° at 60nm
15nm subtends an angle of 15° at 60nm

Question 13

What does 1cm on a 1:500,000 chart represent?

Answer 13

2.7nm or 5km