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DGCA CPL Air Navigation study materials
DGCA CPL Air Navigation study resources

DGCA CPL Air Navigation practice questions

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Question 1General Navigation - Earth, Time, Direction and Magnetism

The most accurate description of the Earth's shape for navigational purposes is:

  1. A flat disc
  2. A perfect sphere
  3. An oblate spheroid Correct answer.
  4. A prolate spheroid

Explanation

The Earth's rotation produces an equatorial bulge, so the equatorial radius (about 6378 km) exceeds the polar radius (about 6357 km), giving a slightly flattened spheroid. This oblate spheroid is the model used for navigation calculations.

Question 2General Navigation - Earth, Time, Direction and Magnetism

One minute of arc of latitude measured along a meridian corresponds to a surface distance of approximately:

  1. 10 nautical miles
  2. 1 statute mile
  3. 1 nautical mile Correct answer.
  4. 1 kilometre

Explanation

The nautical mile is derived from the latitude scale: one minute of arc of latitude equals about one nautical mile (1852 m). This is why distances are measured against the latitude scale on a chart.

Question 3General Navigation - Earth, Time, Direction and Magnetism

Longitude of a place on the Earth's surface is measured:

  1. Eastward from the prime meridian only
  2. East or west of Greenwich, up to 180° Correct answer.
  3. From the Date Line towards Greenwich
  4. From 0° at the Equator up to 90° at each pole

Explanation

Longitude is the arc of the Equator between the prime meridian at Greenwich and the meridian of the place, measured east or west through 0° to 180°. The designation east or west changes at the 180° meridian.

Question 4General Navigation - Earth, Time, Direction and Magnetism

The shortest distance between two points on the Earth's surface is along:

  1. A rhumb line between them
  2. The great circle joining them Correct answer.
  3. The departure meridian
  4. A parallel of latitude

Explanation

A great circle is the intersection of the Earth's surface with a plane passing through its centre, and its minor arc gives the shortest surface distance between two points. All meridians and the Equator are great circles.

Question 5General Navigation - Earth, Time, Direction and Magnetism

Magnetic variation at a place is the angle between:

  1. True north and compass north
  2. Magnetic north and compass north
  3. True north and magnetic north Correct answer.
  4. Heading and track made good

Explanation

Variation is the angle at a place between the true and magnetic meridians, named east or west according to whether magnetic north lies east or west of true north. It is a property of position and changes slowly with time.

Question 6General Navigation - Earth, Time, Direction and Magnetism

Compass deviation in an aircraft is produced by:

  1. Variation of the Earth's field with position
  2. The difference between heading and track
  3. The aircraft's latitude during flight
  4. The aircraft's own magnetic fields Correct answer.

Explanation

Deviation is the angle between magnetic north and compass north and is caused by magnetic fields generated by the aircraft structure, engines and electrical circuits. It depends on the aircraft's heading and changes when electrical loads change.

Question 7General Navigation - Earth, Time, Direction and Magnetism

Coordinated Universal Time (UTC) is the local mean time at:

  1. The 180° meridian
  2. The observer's own position
  3. The standard meridian of the time zone
  4. The prime meridian at 0° longitude Correct answer.

Explanation

UTC is mean solar time at the Greenwich meridian (0° longitude) and serves as the worldwide reference for navigation and timekeeping. Local mean time elsewhere is obtained by applying 15° of longitude per hour.

Question 8General Navigation - Earth, Time, Direction and Magnetism

The International Date Line follows approximately the:

  1. 180° meridian Correct answer.
  2. 90°E meridian
  3. Prime meridian
  4. Equator

Explanation

The Date Line broadly follows the 180° meridian, deviating around land so that islands keep a consistent date. Crossing it eastward means the date is put back one day; crossing westward means it is advanced one day.

Question 9General Navigation - Earth, Time, Direction and Magnetism

At longitude 045°E the local mean time is 12:00. What is UTC?

  1. 15:00
  2. 11:00
  3. 09:00 Correct answer.
  4. 12:00

Explanation

Fifteen degrees of longitude correspond to one hour of time, so 45° equals three hours. East longitude is ahead of UTC, therefore UTC = LMT − 3 h = 09:00.

Question 10General Navigation - Earth, Time, Direction and Magnetism

An aircraft is at longitude 075°W, where UTC is 14:00. The local zone time is:

  1. 09:00 Correct answer.
  2. 14:00
  3. 19:00
  4. 11:00

Explanation

The zone centred on 75°W is five hours behind UTC (UTC − 5). Therefore zone time = 14:00 − 5 h = 09:00.

Question 11General Navigation - Earth, Time, Direction and Magnetism

An aircraft is to fly true course 090° in an area where the magnetic variation is 10°W. The magnetic course to steer is:

  1. 080°
  2. 090°
  3. 100° Correct answer.
  4. 070°

Explanation

With westerly variation the magnetic north lies west of true north, so magnetic bearings are larger than true bearings. Magnetic course = 090° + 10° = 100°.

Question 12General Navigation - Earth, Time, Direction and Magnetism

An aircraft has a magnetic heading of 270° and a deviation of 3°E. The compass heading is:

  1. 270°
  2. 267° Correct answer.
  3. 276°
  4. 273°

Explanation

With easterly deviation, compass north lies east of magnetic north, so the compass reads less than the magnetic heading. Compass heading = 270° − 3° = 267°.

Question 13General Navigation - Earth, Time, Direction and Magnetism

At the magnetic equator, the magnetic dip is:

  1. 90°, with the needle vertical
  2. 45°, dipping towards the south
  3. 45°, dipping towards the north
  4. Zero, with the needle horizontal Correct answer.

Explanation

Dip depends on the vertical component of the Earth's magnetic field, which vanishes at the magnetic equator. There the field is horizontal, so a freely suspended needle lies level.

Question 14General Navigation - Earth, Time, Direction and Magnetism

A rhumb line track is characterised by:

  1. Being the shortest route between two places
  2. Crossing every meridian at the same angle Correct answer.
  3. Cutting each meridian at a changing angle
  4. Requiring a continuously changing heading

Explanation

A rhumb line, or loxodrome, cuts all meridians at a constant angle and follows each parallel, so it can be flown on a constant heading. It is generally longer than the great circle between the same points.

Question 15General Navigation - Earth, Time, Direction and Magnetism

What is the convergency between the meridians 010°E and 020°E at latitude 60°N?

  1. 8.7° Correct answer.
  2. 5°
  3. 20°
  4. 10°

Explanation

Convergency equals the change of longitude multiplied by the sine of the mean latitude: 10° × sin 60° = 10° × 0.866 ≈ 8.7°. This is the angle at which the two meridians meet.

Question 16General Navigation - Earth, Time, Direction and Magnetism

At latitude 60°N, the distance along the parallel between longitudes 010°E and 020°E is approximately:

  1. 600 NM
  2. 520 NM
  3. 120 NM
  4. 300 NM Correct answer.

Explanation

Departure = change of longitude × 60 × cos(latitude) = 10 × 60 × cos 60° = 300 NM. The parallel at 60° has half the radius of the Equator, so the distance is halved.

Question 17General Navigation - Earth, Time, Direction and Magnetism

On about 21 June, the Sun's declination is:

  1. 23.5°S, overhead the Tropic of Capricorn
  2. 0°, overhead the Equator
  3. 66.5°N, overhead the Arctic Circle
  4. 23.5°N, overhead the Tropic of Cancer Correct answer.

Explanation

At the June solstice the Sun reaches its greatest northern declination of about 23.5°, so it is vertically overhead the Tropic of Cancer. This gives the longest day in the Northern Hemisphere.

Question 18General Navigation - Earth, Time, Direction and Magnetism

The equation of time expresses the difference between:

  1. Apparent solar time and UTC
  2. Apparent and mean solar time Correct answer.
  3. Sidereal time and solar time
  4. Local mean time and zone time

Explanation

The equation of time is the difference between apparent (true) solar time and mean solar time at the same place, varying through the year by about ±15 minutes. It arises from the eccentricity of the Earth's orbit and the obliquity of the ecliptic.

Question 19General Navigation - Earth, Time, Direction and Magnetism

At the Equator on the equinoxes, the Sun rises and sets at approximately:

  1. 0700 and 1700 LMT
  2. 0800 and 1600 LMT
  3. 0500 and 1900 LMT
  4. 0600 and 1800 LMT Correct answer.

Explanation

On the Equator the Sun rises and sets about 0600 and 1800 LMT at the equinoxes, giving roughly twelve hours of daylight. At the equinoxes this timing applies at all latitudes.

Question 20General Navigation - Earth, Time, Direction and Magnetism

Civil twilight is the period during which the Sun's centre is:

  1. Between 0° and 6° below the horizon Correct answer.
  2. Between 0° and 12° below the horizon
  3. Exactly on the observer's horizon
  4. Between 6° and 12° below the horizon

Explanation

Civil twilight runs from sunset until the Sun's centre is 6° below the horizon. Nautical twilight covers 6° to 12° and astronomical twilight 12° to 18°.

Question 21General Navigation - Earth, Time, Direction and Magnetism

Lines drawn on a chart joining places of equal magnetic variation are called:

  1. Isoclinals
  2. Isobars
  3. Agonic lines
  4. Isogonals Correct answer.

Explanation

Isogonals join points of equal magnetic variation and are plotted on magnetic charts. The particular isogonal along which variation is zero is called the agonic line.

Question 22General Navigation - Earth, Time, Direction and Magnetism

An aircraft is positioned exactly over the North Pole. Which statement about direction is correct?

  1. Only east and west can be defined there
  2. All directions from the point are south Correct answer.
  3. All directions from the point are north
  4. Longitude alone fixes the heading

Explanation

At the North Pole all meridians converge, and movement away from the pole is along a meridian towards the Equator, that is, southward. True direction is therefore undefined at the exact pole and south in every direction away from it.

Question 23General Navigation - Earth, Time, Direction and Magnetism

A free gyroscope at latitude 60°N has an apparent wander rate of approximately:

  1. 15° per hour
  2. 7.5° per hour
  3. 13° per hour Correct answer.
  4. 0° per hour

Explanation

Apparent wander of a free gyro equals 15° × sin(latitude) per hour. At 60°N this is 15 × 0.866 ≈ 13° per hour, so the gyro must be corrected or slaved to a reference.

Question 24General Navigation - Earth, Time, Direction and Magnetism

At longitude 150°W the local mean time is 10:00 on 10 January. What is UTC?

  1. 18:00 on 10 January
  2. 06:00 on 11 January
  3. 20:00 on 10 January Correct answer.
  4. 00:00 on 11 January

Explanation

150° of longitude equals ten hours, and a west longitude is behind UTC, so UTC = LMT + 10 h = 20:00 on 10 January. The date does not change because the result remains within the same day.

Question 25General Navigation - Earth, Time, Direction and Magnetism

An observer at latitude 45°S finds the Sun's declination to be 20°S. The Sun's meridian altitude is:

  1. 45°
  2. 70°
  3. 65° Correct answer.
  4. 25°

Explanation

When latitude and declination have the same name, meridian altitude = 90° − latitude + declination = 90° − 45° + 20° = 65°. The Sun culminates to the north of the observer.

Question 26General Navigation - Earth, Time, Direction and Magnetism

The Earth's axis of rotation is inclined at approximately what angle to the perpendicular to the plane of its orbit?

  1. 23.5° Correct answer.
  2. 90°
  3. 45°
  4. 66.5°

Explanation

The Earth's obliquity is about 23.5°, which places the tropics at 23.5° latitude. The axis is inclined at 66.5° to the orbital plane itself, not to the perpendicular to that plane.

Question 27General Navigation - Earth, Time, Direction and Magnetism

A great circle on the Earth's surface is produced when the surface is cut by a plane that:

  1. is parallel to the Equator
  2. passes through the centre of the Earth Correct answer.
  3. is tangent to the surface at one point
  4. intersects the surface at two points not through the centre

Explanation

A great circle is formed only when the cutting plane passes through the Earth's centre, dividing the sphere into two equal halves. Such a circle gives the shortest surface path between two points.

Question 28General Navigation - Earth, Time, Direction and Magnetism

One minute of arc measured along a meridian on the Earth's surface corresponds most nearly to:

  1. 1 degree of longitude
  2. 1 kilometre
  3. 1 statute mile
  4. 1 nautical mile Correct answer.

Explanation

The nautical mile is based on 1 minute of arc of latitude and is approximately 1852 metres. One degree of longitude varies in length with latitude, so it is not a fixed distance.

Question 29General Navigation - Earth, Time, Direction and Magnetism

The distance represented by one degree of longitude is greatest at which latitude?

  1. Equator Correct answer.
  2. 45°N
  3. 23.5°N
  4. the Poles

Explanation

The length of a degree of longitude is proportional to the cosine of the latitude. Cosine is greatest at the Equator, so one degree of longitude is longest there.

Question 30General Navigation - Earth, Time, Direction and Magnetism

By international convention, a standard time zone normally spans how many degrees of longitude?

  1. 7.5° of longitude
  2. 30° of longitude
  3. 15° of longitude Correct answer.
  4. 23.5° of longitude

Explanation

A full rotation of 360° in 24 hours gives 15° per hour, so standard time zones are normally 15° wide. Each zone is referenced to a central meridian.

Question 31General Navigation - Earth, Time, Direction and Magnetism

An agonic line on a magnetic chart is a line along which:

  1. magnetic dip is zero
  2. annual change of variation is zero
  3. magnetic variation is zero Correct answer.
  4. compass deviation is zero

Explanation

An agonic line joins places of zero magnetic variation, so true north and magnetic north coincide there. The line of zero dip is instead called the aclinic line or magnetic equator.

Question 32General Navigation - Earth, Time, Direction and Magnetism

Magnetic dip reaches 90° at which location?

  1. the magnetic equator
  2. the magnetic poles Correct answer.
  3. the geographic Equator
  4. any point on an isogon

Explanation

At the magnetic poles the Earth's magnetic field is vertical, so a freely suspended magnetic needle would align vertically and dip is 90°. At the magnetic equator the field is horizontal and dip is zero.

Question 33General Navigation - Earth, Time, Direction and Magnetism

The north-seeking end of a freely suspended magnetic compass needle aligns itself toward:

  1. the south geographic pole
  2. magnetic north Correct answer.
  3. the Earth's rotational axis
  4. the geographic North Pole

Explanation

A magnetic compass responds to the horizontal component of the Earth's magnetic field. Its north-seeking end therefore aligns approximately with magnetic north, not with the geographic pole.

Question 34General Navigation - Earth, Time, Direction and Magnetism

At longitude 120°E the local mean time is 08:00 on 2 May. What is UTC?

  1. 12:00 on 2 May
  2. 04:00 on 2 May
  3. 00:00 on 2 May Correct answer.
  4. 16:00 on 1 May

Explanation

Longitude 120°E is 8 hours ahead of UTC because 120° ÷ 15° per hour = 8 hours. UTC is therefore found by subtracting 8 hours from LMT, giving 00:00 on 2 May.

Question 35General Navigation - Earth, Time, Direction and Magnetism

An aircraft at longitude 135°W has UTC 18:00 on 5 June. What is the local standard time (zone time)?

  1. 15:00 on 5 June
  2. 09:00 on 5 June Correct answer.
  3. 09:00 on 6 June
  4. 03:00 on 5 June

Explanation

Longitude 135°W lies in the UTC−9 zone because 135° ÷ 15° per hour = 9 hours. Zone time is therefore 18:00 − 9 hours = 09:00 on 5 June.

Question 36General Navigation - Earth, Time, Direction and Magnetism

The great-circle distance between positions on the same meridian at 20°N and 50°N is approximately:

  1. 2400 NM
  2. 1800 NM Correct answer.
  3. 1500 NM
  4. 900 NM

Explanation

The positions differ by 30° of latitude, and 1° of latitude is about 60 NM along a meridian. The distance is therefore 30 × 60 = 1800 NM.

Question 37General Navigation - Earth, Time, Direction and Magnetism

At latitude 30°N, what is the departure between longitudes 010°E and 040°E?

  1. 1800 NM
  2. 1559 NM Correct answer.
  3. 2078 NM
  4. 900 NM

Explanation

Departure equals change of longitude in minutes of arc multiplied by the cosine of the latitude. Here 30° × 60 × cos 30° = 1559 NM approximately.

Question 38General Navigation - Earth, Time, Direction and Magnetism

An aircraft is to fly true course 225°. The magnetic variation is 8°E and the deviation is 4°W. What compass course is required?

  1. 217°
  2. 233°
  3. 229°
  4. 221° Correct answer.

Explanation

Variation east is subtracted when converting true to magnetic, giving 225° − 8° = 217° magnetic. Deviation west is added when converting magnetic to compass, giving 217° + 4° = 221° compass.

Question 39General Navigation - Earth, Time, Direction and Magnetism

Compass heading 060° is being flown with deviation 5°E and variation 12°W. What is the true heading?

  1. 087°
  2. 077° Correct answer.
  3. 067°
  4. 043°

Explanation

Deviation east is added when converting compass to magnetic, giving 060° + 5° = 065° magnetic. Variation west is added when converting magnetic to true, giving 065° + 12° = 077° true.

Question 40General Navigation - Earth, Time, Direction and Magnetism

When crossing the International Date Line travelling westbound, the calendar date should be:

  1. retarded by one day
  2. left unchanged
  3. advanced by one day Correct answer.
  4. advanced by 12 hours

Explanation

Westbound across the International Date Line, the traveller moves from the eastern side to the western side, so the calendar date advances by one day. An eastbound crossing retards the date by one day.

Question 41General Navigation - Earth, Time, Direction and Magnetism

On which dates is the Sun's declination approximately 0°?

  1. 21 March/23 September Correct answer.
  2. 21 June only
  3. 21 June and 22 December
  4. 3 January and 4 July

Explanation

The Sun's declination is zero at the equinoxes, when the Sun is over the Equator. These occur about 21 March and 23 September.

Question 42General Navigation - Earth, Time, Direction and Magnetism

An observer at latitude 30°N sees the Sun on the meridian with declination 10°N. What is the Sun's altitude?

  1. 70° Correct answer.
  2. 50°
  3. 80°
  4. 60°

Explanation

Meridian altitude is 90° minus the difference between latitude and declination. The difference here is 30° − 10° = 20°, so the altitude is 90° − 20° = 70°.

Question 43General Navigation - Earth, Time, Direction and Magnetism

At the June solstice in the Northern Hemisphere, the Sun rises:

  1. due north
  2. north of east Correct answer.
  3. due east
  4. south of east

Explanation

At the June solstice the Sun's declination is about 23.5°N, so it rises north of east and sets north of west. Due east occurs at the equinoxes.

Question 44General Navigation - Earth, Time, Direction and Magnetism

A free gyroscope at 40°N appears to wander about its vertical axis in which direction when viewed from above?

  1. directly toward the nearer pole
  2. directly toward the Equator
  3. anticlockwise
  4. clockwise Correct answer.

Explanation

Apparent wander of a free gyro is caused by the Earth's rotation and is clockwise when viewed from above in the Northern Hemisphere. Its rate is about 15° × sin(latitude) per hour, but the direction is clockwise.

Question 45General Navigation - Earth, Time, Direction and Magnetism

At a place where the true bearing of an object is 135° and its magnetic bearing is 120°, the magnetic variation is:

  1. 15°W
  2. 255°W
  3. 15°E Correct answer.
  4. 255°E

Explanation

The magnetic bearing is 15° smaller than the true bearing, which means magnetic north lies east of true north. The variation is therefore 15°E.

Question 46General Navigation - Earth, Time, Direction and Magnetism

An aircraft at longitude 170°E has local mean time 23:00 on 10 April. What is UTC?

  1. 10:20 on 10 April
  2. 11:40 on 11 April
  3. 11:40 on 10 April Correct answer.
  4. 10:20 on 11 April

Explanation

Longitude 170°E is 11 hours 20 minutes ahead of UTC because 170° × 4 minutes per degree = 680 minutes. Subtracting this from 23:00 on 10 April gives 11:40 UTC on 10 April.

Question 47General Navigation - Earth, Time, Direction and Magnetism

The convergency between meridians 030°W and 050°E at latitude 45°N is approximately:

  1. 56.6° Correct answer.
  2. 113.1°
  3. 80.0°
  4. 40.0°

Explanation

Convergency between two meridians equals change of longitude multiplied by the sine of the latitude. The change is 80°, and 80° × sin 45° = 56.6°.

Question 48General Navigation - Earth, Time, Direction and Magnetism

An observer at latitude 50°S finds the Sun on the meridian with an altitude of 20° and bearing due north. What is the Sun's declination?

  1. 20°N Correct answer.
  2. 70°N
  3. 70°S
  4. 20°S

Explanation

A meridian altitude of 20° means the Sun is 70° from the observer's zenith. Because the Sun bears north from 50°S, its declination must be north of the observer, giving 20°N.

Question 49General Navigation - Earth, Time, Direction and Magnetism

What is the great-circle distance along the Equator between longitudes 170°E and 170°W?

  1. 1200 NM Correct answer.
  2. 10800 NM
  3. 600 NM
  4. 20400 NM

Explanation

The shorter longitude difference between 170°E and 170°W is 20° across the 180° meridian. On the Equator, 1° of longitude is about 60 NM, so the great-circle distance is 20 × 60 = 1200 NM.

Question 50General Navigation - Earth, Time, Direction and Magnetism

On about 21 December at latitude 70°N, the Sun:

  1. reaches a meridian altitude of 3.5°
  2. remains below the horizon all day Correct answer.
  3. is circumpolar
  4. rises due south at noon

Explanation

On 21 December the Sun's declination is about 23.5°S. At 70°N the noon altitude would be 90° − (70° + 23.5°) = −3.5°, so the Sun does not rise and remains below the horizon.