Nav

Question 1

35. What happens to the ETP if you have a headwind component on the outbound leg?

Answer 1

a. The ETP will move towards the aerodrome of destination.
The position of the ETP will always move into wind, away from the mid point.

Question 2

36. Definition of ETP

Answer 2

a. The ETP is that point along track which it will take the same time to continue to the destination, or return to the departure aerodrome.
ETP is a time consideration

Question 3

37. ETP Formula

Answer 3

x=DH/(O+H)
X= Distance from departure aerodrome to ETP
D= Distance from A-B
H= The groundspeed home from ETP (TAS corrected for wind)
O= The groundspeed onwards from ETP to B (TAS corrected for wind)

Question 4

38. Definition of PNR

Answer 4

a. Beyond the PNR there is insufficient fuel to return to the departure aerodrome with all the regulatory fuel reserves intact.
The PNR will always lie at or beyond the ETP between two aerodromes
PNR is a fuel consideration

Question 5

39. PNR Formula

Answer 5

D=EOH/(O+H)
D= Distance to PNR
O= The groundspeed out to the PNR
H= The groundspeed home from the PNR
T= Time out to the PNR
E= Aircrafts safe endurance (i.e. allowing for reserves) in hours. Note, when calculating safe endurance time must be in decimals (6 minutes = 0.1).

Question 6

40. What happens to the PNR with changes in wind?

Answer 6

a. In nil-wind the PNR will be at a distance from the departure aerodrome equal to half the safe endurance.
Any wind component, head or tailwind, will bring the PNR closer to the departure point in distance.

Question 7

41. What fuel is included in the PNR safe endurance?

Answer 7

a. Total fuel less unusable, reserves, holding, instrument approaches, possible diversions or any other contingences that may apply.

Question 8

42. You are early at ETP, which way does it move.

Answer 8

a. The wind is less than forecast, the ETP moves away from aerodrome of destination.

Question 9

43. You are 10 minutes ahead on your flight plan going between Wellington and the Chatham’s. What does this do to the position of your ETP?

Answer 9

a. The actual headwind is less that the forecast. The ETP moves away from the aerodrome of destination.

Question 10

44. Taking off Wellington to Chatham’s. You are behind on your ETA. What is this going to do to your ETP

Answer 10

a. Wind is stronger than what was forecast, ETP moves towards the destination.

Question 11

46. A question with take-off time in local and flight time, what is landing time in a different time zone

Answer 11

a. Calculate the degrees difference of longitude.
360/24=15, therefore ever 15 degrees of travel = 1 hour time difference.
(140 degrees /15 = 9.3 hours difference = 3 hours 18 minutes)
Traveling east is behind time, so subtract time.
Traveling west is ahead of time, so add time.

Question 12

48. Simple time conversions ie leave xx at 0615 Local on Saturday. Land XX at xx Local. Given UTC at each location. What is flight time?

Question 13

51. Formula for 1 on 60 rule

Answer 13

60/Distance gone=Track Error/Distance off

Question 14

1. 1:100,000 chart scale to NM

Answer 14

(chart length)/(earth ditance)=Scale

Question 15

1. What do straight lines represent on a Lambert’s chart?

Answer 15

a. Great circle
(Mrs Convex Pole= Mercator chart rhumb lines are straight, and great circles are convex to the nearest pole. Lambert charts are opposite).

Question 16

5. Flying the most direct route on a Mercator chart what is it and what does it look like?

Answer 16

a. Curve Convex to the pole (GC track)
(Mrs Convex Pole= Mercator chart rhumb lines are straight, and great circles are convex to the nearest pole. Lambert charts are opposite).

Question 17

6. Great Circle

Answer 17

a. A circle drawn on the face of the earth whose radius is the earth. Its plane passes through the centre of the earth. It is the shortest distance between two places.

Question 18

7. Small Circle

Answer 18

a. Any circle drawn on the earth whose radius is not the earth. Its plane does not pass through the centre of the earth.

Question 19

8. Rhumb Line

Answer 19

a. A line drawn on the centre of the earth which cuts each meridian at the same angle.

Question 20

9. Parallels of latitude

Answer 20

a. Small circles joining points of equal latitude – except equator, which is a great circle
All are rhumb lines
Lie east to west

Question 21

10. Meridians of longitude

Answer 21

a. Semi-great circles passing thru the poles

Question 22

11. Prime Meridian

Answer 22

a. A semi-great circle passing through the poles and also Greenwich. Known as the Greenwich meridian. It defines a longitude of zero degrees.
0000UTC is said to exist when the sun is directly over head the anti meridian (180)

Question 23

12. Isogonal

Answer 23

a. Line joining points of equal variation

Question 24

13. Nautical mile

Answer 24

a. Distance on the surface of the earth which subtends an angle of one minute of arc at the centre of the earth
6080 ft
One degree ofchange of latitude along a meridian represents a distance of 60nm (60min of arc)

Question 25

What is the departure formula, and when is it used?

Answer 25

a. Necessary due to the fact that 1 degree of longitude is only equal to 60nm at the equator. Any deviation from the equator needs reference to the departure formula. Distance (nm) = change of long x cos lat

Question 26

What is earth convergency and its formula?

Answer 26

a. The angle of inclination between two meridians at any given latitude b. Earth convergency = change in long x sin mean lat

Question 27

16. Rotation of Earth

Answer 27

a. 900kts at equator 900 x cos lat = speed at a given latitude

Question 28

17. Mercator projection

Answer 28

a. Cylindrical projection All meridians appear as straight lines with parallel spacing All parallels are straight lines with the distance between them increasing with increase in latitude Poles are unable to be projected Lat and long intersect at right angles A Rhumb line will appear as a straight line A great circle will appear as a curved line convex to the nearest pole

Question 29

18. Lambert Projection

Answer 29

This utilizes a conical projection with the apex of the cone directly above the pole Meridians appear as straight lines converging towards the pole Parallels appear as straight lines with the distance between them being constant Lats and Longs intersect at right angles Rhumb lines appear as curved lines convex to the nearest pole Great circles appear as straight lines

Question 30

19. Conversion Angle

Answer 30

a. This is the angle between the great circle track between two points and the rhumb line track between two points. It is equal to half earth convergency. Conversion angle = 0.5 change in long x sin mean lat

Question 31

20. Orthomorphism

Answer 31

a. All chart used for nav must have these two qualities. i. The scale on the chart must be correct to the scale nearby (equal scale expansion) ii. Parallels and meridians must cross at right angles.

Question 32

21. Time to Arc

Answer 32

a. 1 of arc = 4 min. 15’ of arc = 1 min. 1’ of arc = 4 sec.