DGCA Air Navigation: The Earth, Directions & Great Circles Questions
76 exam-style The Earth, Directions & Great Circles questions for the DGCA Air Navigationpaper (CPL & ATPL). The first 12 are free below with answers and explanations — sign up free to practise all of them with progress tracking.
- Q1
Route 'A' (44°N 026°E) to 'B' (46°N 024°E) forms an angle of 35° with longitude 026°E. Average magnetic variation between 'A' and 'B' is 3°E.What is the average magnetic course from 'A' to 'B'?
- A 322°
- B328°
- C 032°
- D 038°
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Correct answer: A. 322°
The track from A to B lies 35 degrees west of the 026E meridian, giving a true course of about 325; applying 3 degrees of easterly variation gives a magnetic course of about 322.
- Q2
The rhumb-line distance between points A (60°00'N 002°30'E) and B (60°00'N 007°30'W) is:
- A300 NM
- B450 NM
- C600 NM
- D150 NM
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Correct answer: A. 300 NM
Both points lie on the 60N parallel, 10 degrees of longitude apart, so departure equals 600 minutes times the cosine of 60 degrees, which is 300 NM.
- Q3
An aircraft flies the following rhumb line tracks and distances from position 04°00'N 030°00'W :600 NM South, then 600 NM East, then 600 NM North, then 600 NM West.The final position of the aircraft is:
- A 04°00'N 029°58'W
- B 04°00'N 030°02'W
- C 04°00'N 030°00'W
- D03°58'N 030°02'W
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Correct answer: A. 04°00'N 029°58'W
The eastward leg is flown at 6S and the westward leg at 4N, so the greater change of longitude per degree at the lower latitude leaves the aircraft slightly east of the start, at 04N 029 58W.
- Q4
What is the final position after the following rhumb line tracks and distances have been followed from position 60°00'N 030°00'W?South for 3600 NM, East for 3600 NM, North for 3600 NM, West for 3600 NM.The final position of the aircraft is:
- A60°00'N 090°00'W
- B60°00'N 030°00'E
- C59°00'N 060°00'W
- D59°00'N 090°00'W
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Correct answer: A. 60°00'N 090°00'W
Each 3600 NM leg equals 60° of latitude change on the meridians; south then north returns to 60°N, but on the equator 3600 NM east spans 60° of longitude while at 60°N the westbound 3600 NM spans 120° of longitude (departure = d.long × cos 60°), so the net shift is 60° west, giving 60°00'N 090°00'W.
- Q5
An aircraft departing A(N40º 00´ E080º 00´) flies a constant true track of 270º at a ground speed of 120 kt. What are the coordinates of the position reached in 6 HR?
- A N40º 00´ E064º 20´
- B N40º 00´ E070º 30´
- C N40º 00´ E060º 00´
- D N40º 00´ E068º 10´
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Correct answer: A. N40º 00´ E064º 20´
A constant true track of 270° is flown along the parallel of latitude, so 120 kt for 6 hours covers 720 NM of departure; dividing by the cosine of 40° gives about 15°40' of longitude change, moving from E080°00' to E064°20'.
- Q6
A flight is to be made from 'A' 49°S 180°E/W to 'B' 58°S, 180°E/W.The distance in kilometres from 'A' to 'B' is approximately:
- A1000
- B1222
- C 540
- D 804
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Correct answer: A. 1000
Both points lie on the same meridian, so the distance is purely the 9° change of latitude, which is 540 NM; converting at 1.852 km per nautical mile gives approximately 1000 km.
- Q7
An aircraft departs from position A (04°10' S 178°22'W) and flies northward following the meridian for 2950 NM. It then flies westward along the parallel of latitude for 382 NM to position B. The coordinates of position B are?
- A45°00'N 169°22W
- B53°20'N 172°38'E
- C45°00'N 172°38'E
- D53°20'N 169°22W
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Correct answer: C. 45°00'N 172°38'E
This Explanation is Coming Soon
- Q8
An aircraft at position 60°N 005°W tracks 090°(T) for 315 km.On completion of the flight the longitude will be:
- A 000°40'E
- B005°15'E
- C 002°10'W
- D 000°15'E
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Correct answer: A. 000°40'E
A 315 km leg is about 170 NM, and on a track of 090° along the parallel this is the departure; dividing by the cosine of 60° gives roughly 5°40' of longitude change, moving east from 005°W to about 000°40'E.
- Q9
Parallels of latitude, except the equator, are:
- ARhumb lines
- BGreat circles
- C both Rhumb lines and Great circles
- D are neither Rhumb lines nor Great circles
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Correct answer: A. Rhumb lines
Every parallel except the equator is a small circle, so it is a rhumb line (constant direction, due east–west) but not a great circle; only the equator is both.
- Q10
The angle between the true great-circle track and the true rhumb-line track joining the following points: A (60° S 165° W) B (60° S 177° E), at the place of departure A, is:
- A15.6°
- B5.2°
- C9°
- D7.8°
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Correct answer: D. 7.8°
This Explanation is Coming Soon
- Q11
The 'departure' between positions 60°N 160°E and 60°N 'x' is 900 NM.What is the longitude of 'x'?
- A 170°W
- B140°W
- C 145°E
- D 175°E
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Correct answer: A. 170°W
A departure of 900 NM at 60°N corresponds to a longitude change of 900 ÷ cos 60° = 1800' = 30°; measured east from 160°E this crosses the antimeridian to 170°W.
- Q12
An aircraft at latitude 02°20'N tracks 180°(T) for 685 km.On completion of the flight the latitude will be:
- A03°50'S
- B04°10'S
- C 04°30'S
- D 09°05'S
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Correct answer: A. 03°50'S
685 km equals about 370 NM, which is 370 minutes of latitude or 6°10' of arc along a meridian. Tracking due south from 02°20'N the aircraft crosses the equator and ends at 03°50'S.
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