I85PREP
⌘ K
Brunei DCA CPL(A) General Navigation study materials
Brunei DCA CPL(A) General Navigation study resources

Brunei DCA CPL(A) General Navigation practice questions

One question at a time. Build your Brunei DCA CPL(A) General Navigation understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

Which model of the Earth is used for most navigational calculations on charts and in flight planning?

  1. An oblate spheroid flattened at the poles Correct answer.
  2. A prolate spheroid elongated at the poles
  3. A flat disc with the North Pole at the centre
  4. A perfect sphere with a mean radius of about 6371 km

Explanation

The Earth is slightly flattened at the poles and bulging at the equator, so an oblate spheroid is the standard model. This shape explains why the polar diameter is shorter than the equatorial diameter. A sphere is only an approximation used for simple manual work.

Question 2Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

Approximately what is the length of one minute of latitude measured along a meridian?

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

Explanation

One minute of latitude corresponds to one nautical mile, by definition of the nautical mile based on the meridian arc. This relationship holds essentially constant along any meridian. It is the foundation of position plotting on charts.

Question 3Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

What is the maximum latitude that can be reached on Earth?

  1. 45 degrees
  2. 180 degrees
  3. 66.5 degrees
  4. 90 degrees Correct answer.

Explanation

Latitude is measured from the equator to the poles, so the poles lie at 90 degrees north and south. Values beyond 90 degrees are impossible for latitude. Longitude, by contrast, extends to 180 degrees east and west.

Question 4Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

How is longitude measured?

  1. From the prime meridian eastward and westward up to 180 degrees Correct answer.
  2. From the observer's local meridian to the antimeridian
  3. From the North Pole southward to the equator
  4. From the equator eastward and westward up to 90 degrees

Explanation

Longitude is the angular distance east or west of the prime meridian, measured up to 180 degrees in each direction. The prime meridian passes through Greenwich. Latitude, not longitude, is measured from the equator.

Question 5Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

What defines a great circle on the surface of the Earth?

  1. A circle parallel to the equator
  2. A circle centred on the observer's position
  3. A circle whose plane passes through the Earth's centre Correct answer.
  4. A circle whose plane is perpendicular to the polar axis

Explanation

A great circle is formed where a plane through the Earth's centre intersects the surface, dividing the sphere into two equal halves. Its radius equals the Earth's radius. Only the equator is both a great circle and a parallel of latitude.

Question 6Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

Which statement correctly describes a rhumb line?

  1. It crosses every meridian at the same angle Correct answer.
  2. It coincides with a great circle on all charts
  3. It crosses each meridian at 90 degrees
  4. It is always the shortest path between two points

Explanation

A rhumb line, or loxodrome, maintains a constant track angle relative to all meridians. On a Mercator chart it plots as a straight line. It is generally longer than the great circle between the same points.

Question 7Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

On a Mercator chart, what is the appearance of a rhumb line between two points?

  1. A line parallel to the nearest meridian
  2. A straight line Correct answer.
  3. A series of arcs
  4. A curved line concave to the equator

Explanation

The Mercator projection is constructed so that a constant track angle plots as a straight line. This makes it the preferred chart for plotting rhumb-line tracks. Great circles appear curved on the same chart.

Question 8Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

An aircraft flies from position A to position B along the great circle. Compared with the rhumb line between the same points, the great circle is generally:

  1. Identical in distance at all latitudes
  2. Shorter in distance but requires continuous heading changes Correct answer.
  3. Shorter only when crossing the equator
  4. Longer in distance but simpler to steer

Explanation

The great circle is the shortest surface distance between two points, but its track angle changes continuously along the route. The rhumb line keeps a constant heading but covers a greater distance, except along the equator or a meridian.

Question 9Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

How many degrees of arc separate the equator from the North Pole?

  1. 180 degrees
  2. 45 degrees
  3. 90 degrees Correct answer.
  4. 60 degrees

Explanation

The equator is at 0 degrees latitude and the pole at 90 degrees, so the arc between them is 90 degrees. This is one quarter of a full circle. It equals 5400 minutes of arc, or about 5400 nautical miles.

Question 10Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

Two positions lie on the same meridian, 3 degrees of latitude apart. What is the approximate surface distance between them?

  1. 240 nautical miles
  2. 120 nautical miles
  3. 60 nautical miles
  4. 180 nautical miles Correct answer.

Explanation

Each degree of latitude is about 60 nautical miles, so 3 degrees equals roughly 180 nautical miles. This applies along any meridian. Longitude spacing, by contrast, varies with latitude.

Question 11Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

Why does the length of one degree of longitude decrease towards the poles?

  1. Because the equator is a small circle
  2. Because latitude degrees become longer near the poles
  3. Because the Earth's radius increases towards the poles
  4. Because meridians converge at the poles Correct answer.

Explanation

Meridians converge at the poles, so the physical spacing between them shrinks with increasing latitude. At the equator one degree of longitude is about 60 nautical miles, but at 60 degrees latitude it is about 30 nautical miles. Latitude spacing, by contrast, stays nearly constant.

Question 12Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

What is the prime meridian used as the reference for longitude in aviation?

  1. The meridian through Tokyo
  2. The meridian through Washington
  3. The meridian through Paris
  4. The meridian through Greenwich Correct answer.

Explanation

By international agreement the prime meridian passes through Greenwich, near London, and is defined as 0 degrees longitude. Longitudes are measured east and west from it. Other historic meridians have been superseded.

Question 13Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

What is the antipodal point of a position at 20 degrees north, 40 degrees east?

  1. 20 degrees south, 40 degrees west
  2. 20 degrees south, 140 degrees west Correct answer.
  3. 20 degrees north, 140 degrees west
  4. 20 degrees south, 40 degrees east

Explanation

The antipode has the opposite latitude and a longitude differing by 180 degrees. So 20 degrees north becomes 20 degrees south, and 40 degrees east becomes 140 degrees west. The sum of the two longitudes must be 180 degrees.

Question 14Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

An aircraft follows a rhumb line due east along a parallel of latitude. What is true of its track?

  1. The track angle gradually changes towards the pole
  2. The track is the shortest path to the destination
  3. The track angle remains 090 degrees throughout Correct answer.
  4. The track follows a great circle

Explanation

A rhumb line keeps a constant angle to the meridians, so due east along a parallel stays at a constant track of 090 degrees. Because a parallel is a small circle, this path is not the shortest distance. The great circle between the same points would curve poleward.

Question 15Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

Why is the great circle route rarely flown as a single constant heading?

  1. Because aircraft cannot fly at high latitudes
  2. Because great circles cannot be plotted on charts
  3. Because the great circle is always longer than the rhumb line
  4. Because the track angle changes continuously along the route Correct answer.

Explanation

A great circle crosses each meridian at a different angle, so the heading must be adjusted continuously to stay on track. In practice the route is flown as a series of rhumb-line legs approximating the great circle. This is why flight plans list many waypoints.

Question 16Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

A position is given as 45 degrees south, 170 degrees east. Which description is correct?

  1. Northern hemisphere, eastern hemisphere
  2. Southern hemisphere, western hemisphere
  3. Southern hemisphere, eastern hemisphere Correct answer.
  4. Northern hemisphere, western hemisphere

Explanation

A south latitude places the position in the southern hemisphere. An east longitude places it in the eastern hemisphere, since eastern longitudes run from 0 to 180 degrees east. Both coordinates must be read independently.

Question 17Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

At 60 degrees north, what is the approximate length of one degree of longitude?

  1. 30 nautical miles Correct answer.
  2. 45 nautical miles
  3. 15 nautical miles
  4. 60 nautical miles

Explanation

The spacing of meridians shrinks as the cosine of the latitude. At 60 degrees north the cosine is 0.5, so one degree of longitude is about 30 nautical miles compared with 60 at the equator. This relationship is fundamental to chart scale and distance measurement.

Question 18Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

Two aircraft depart the same point on the equator and fly to the same destination on the equator on opposite sides of the Earth. Which route type gives the shorter distance for each?

  1. The rhumb line along the equator
  2. The route via the nearer pole
  3. The great circle along the equator
  4. Both are equal in length Correct answer.

Explanation

On the equator a great circle and a rhumb line coincide, because the equator is both a great circle and a parallel of latitude. The two paths are therefore identical in length. The special case arises only along the equator or along a meridian.

Question 19Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

A great circle track between two points in the northern hemisphere bulges poleward on a Mercator chart. What does this indicate about the route?

  1. The route is a rhumb line
  2. The route stays at the latitude of the departure point
  3. The route crosses the equator
  4. The route reaches a higher latitude than either endpoint Correct answer.

Explanation

On a Mercator chart a great circle appears curved toward the pole in the hemisphere of the route. This means the aircraft reaches a maximum latitude, the vertex, greater than either endpoint. The rhumb line, by contrast, never exceeds the latitude of the endpoints.

Question 20Basic Navigation Concepts: Earth's Shape, Coordinate Systems, Great Circles and Rhumb Lines

An aircraft flies from position A (0°N, 10°E) to position B (0°N, 50°E), both on the equator. Which statement about this route is correct?

  1. The route is a rhumb line but not a great circle, so the track changes continuously.
  2. The route is neither a great circle nor a rhumb line, and the track remains 090° throughout.
  3. The route is both a great circle and a rhumb line, and the track remains 090° throughout. Correct answer.
  4. The route is a great circle but not a rhumb line, so the track changes continuously.

Explanation

The equator is a great circle because its plane passes through the centre of the Earth, and it also cuts every meridian at the same angle, which makes it a rhumb line as well. Flying due east along it therefore keeps a constant track of 090° while still following the shortest path between the two points. This dual property holds only for the equator and for meridians.

Question 21Charts and Chart Projections: Properties, Uses and Limitations

On a Lambert conformal conic chart covering the middle latitudes, what is the principal advantage for navigation?

  1. Distances can be measured with a single scale everywhere
  2. Great circles plot as straight lines anywhere on the sheet
  3. Angles measured on the chart closely equal true angles on the Earth Correct answer.
  4. The whole globe can be shown without any distortion

Explanation

A conformal projection preserves the shape of small features, so the angle between two lines on the chart equals the angle between the corresponding tracks on the Earth. This lets a pilot plot a bearing directly with a protractor. Straight lines on such a chart are not true great circles, and scale still varies with latitude.

Question 22Charts and Chart Projections: Properties, Uses and Limitations

On a Mercator chart used for air navigation, what happens to the scale as latitude increases?

  1. It decreases steadily toward the poles
  2. It remains exactly constant everywhere
  3. It increases, so the scale is largest near the poles Correct answer.
  4. It increases toward the equator and decreases toward the poles

Explanation

Mercator is a conformal cylindrical projection in which the meridians are drawn as parallel straight lines. To keep shapes correct, the spacing of the parallels must increase toward the poles, so chart scale grows larger at high latitude. This is why Mercator charts are unsuitable for polar navigation.

Question 23Charts and Chart Projections: Properties, Uses and Limitations

Which property defines a great circle on the surface of the Earth?

  1. A circle whose plane is parallel to the equator
  2. A circle whose plane passes through the Earth's centre Correct answer.
  3. Any circle drawn on the Earth's surface with a compass
  4. A line of constant latitude other than the equator

Explanation

A great circle is formed where a plane through the centre of the sphere cuts the surface, dividing it into two equal halves. Its radius equals the Earth's radius, and it gives the shortest surface distance between two points. The equator and all meridians are examples.

Question 24Charts and Chart Projections: Properties, Uses and Limitations

What is the main limitation of a gnomonic chart for general navigation?

  1. Bearings cannot be measured on it at all
  2. It is conformal but not equal-area
  3. It cannot show more than a small part of the Earth without severe distortion Correct answer.
  4. Great circles cannot be plotted on it

Explanation

The gnomonic projection is derived from a plane tangent to the Earth, so distortion grows rapidly away from the point of tangency. Only a limited area, generally less than a hemisphere, can be shown usefully. Its value lies in the fact that great circles plot as straight lines.

Question 25Charts and Chart Projections: Properties, Uses and Limitations

On a direct Mercator chart, how are the meridians and parallels drawn?

  1. Meridians as curves converging at the poles and parallels as curves
  2. Meridians as straight lines radiating from a point and parallels as arcs
  3. Meridians as parallel lines and parallels as concentric circles
  4. Meridians as parallel straight lines and parallels as parallel straight lines Correct answer.

Explanation

Mercator is a cylindrical projection, so the meridians appear as equally spaced straight vertical lines and the parallels as straight horizontal lines. The spacing of the parallels increases with latitude to preserve conformality. The resulting graticule is a rectangular grid.

Question 26Charts and Chart Projections: Properties, Uses and Limitations

Which chart projection shows a great circle track as a straight line, making it useful for plotting long-range routes?

  1. Polar stereographic
  2. Lambert conformal conic
  3. Gnomonic Correct answer.
  4. Transverse Mercator

Explanation

On the gnomonic projection every great circle plots as a straight line, because the projection plane is tangent to the Earth and great-circle planes project as straight lines. This makes it convenient for drawing a great-circle route before transferring it to a conformal chart. The other projections show great circles as curves.

Question 27Charts and Chart Projections: Properties, Uses and Limitations

A pilot measures a track of 090 degrees on a Lambert conformal conic chart. What does this angle represent?

  1. The rhumb-line track between the two points
  2. The magnetic track at the point of measurement
  3. The grid track referenced to the central meridian
  4. The true track at the point of measurement Correct answer.

Explanation

Because the projection is conformal, angles measured on the chart equal the true angles on the Earth at that point. The measured angle is therefore the true track, not a magnetic or grid direction. Magnetic variation and grid convergence must be applied separately if those references are needed.

Question 28Charts and Chart Projections: Properties, Uses and Limitations

Why does a straight line drawn between two points on a Mercator chart not represent the shortest route?

  1. Because the chart scale varies with longitude
  2. Because meridians converge on a Mercator chart
  3. Because a straight line is a rhumb line of constant track, longer than the great circle Correct answer.
  4. Because Mercator charts cannot show straight lines

Explanation

On Mercator a straight line crosses every meridian at the same angle, so it is a rhumb line. Except along the equator or a meridian, the rhumb line is longer than the great circle joining the same points. The great circle appears as a curve concave toward the nearer pole.

Question 29Charts and Chart Projections: Properties, Uses and Limitations

On a polar stereographic chart of the northern hemisphere, a straight line drawn from a point near the pole toward the equator represents approximately what?

  1. A great circle track Correct answer.
  2. A rhumb line at constant track
  3. A line of constant magnetic variation
  4. A parallel of latitude

Explanation

In the polar stereographic projection, meridians appear as straight lines radiating from the pole, and any straight line not through the pole is close to a great circle. This makes the chart convenient for high-latitude navigation. It is not a rhumb line except along a meridian.

Question 30Charts and Chart Projections: Properties, Uses and Limitations

What is chart convergence on a Lambert conformal conic chart?

  1. The angle between the two meridians bounding the chart, which indicates the spread of the graticule Correct answer.
  2. The rate at which chart scale changes with latitude
  3. The angle between a great circle and a rhumb line at a point
  4. The difference between true north and magnetic north at a point

Explanation

Convergence is the total angle at the apex between the extreme meridians of the chart, reflecting how much the meridians converge. It is used with grid navigation to convert between true and grid directions. It is a property of the chart layout, not of magnetism or scale.

Question 31Charts and Chart Projections: Properties, Uses and Limitations

A chart is described as having a scale of 1:500 000. What does this mean?

  1. The chart is accurate to within 500 000 metres
  2. The chart covers 500 000 square kilometres
  3. One kilometre on the chart represents 500 000 metres on the Earth
  4. One unit on the chart represents 500 000 of the same units on the Earth Correct answer.

Explanation

A representative fraction expresses the ratio of chart distance to Earth distance in the same units. Thus one centimetre on the chart represents 500 000 centimetres, or five kilometres, on the ground. The scale says nothing about area covered or positional accuracy.

Question 32Charts and Chart Projections: Properties, Uses and Limitations

Why is a Mercator chart unsuitable for navigation near the poles?

  1. Meridians converge to a point, making bearings unreadable
  2. The scale distortion becomes extreme and the poles cannot be shown Correct answer.
  3. Magnetic variation cannot be depicted
  4. Great circles plot as straight lines there

Explanation

On Mercator the parallel spacing is stretched increasingly toward the poles, so scale distortion becomes enormous and the poles lie at infinity. The chart is therefore impractical for high-latitude work. Polar stereographic charts are used instead.

Question 33Charts and Chart Projections: Properties, Uses and Limitations

Which statement correctly compares a large-scale chart with a small-scale chart?

  1. Both cover the same area but differ only in colour
  2. The large-scale chart covers a smaller area with more detail Correct answer.
  3. The large-scale chart covers a larger area with less detail
  4. The small-scale chart has a larger representative fraction

Explanation

A large-scale chart has a larger representative fraction, such as 1:50 000, so it shows a smaller area in greater detail. A small-scale chart, such as 1:1 000 000, covers a wide area with less detail. The terms refer to the size of the fraction, not the sheet.

Question 34Charts and Chart Projections: Properties, Uses and Limitations

On a transverse Mercator chart, along which line is the scale exactly correct?

  1. The central meridian Correct answer.
  2. Every meridian equally
  3. The standard parallel
  4. The equator

Explanation

In the transverse Mercator projection the cylinder is wrapped around the Earth at right angles to the polar axis, touching along a chosen central meridian. Scale is true on that central meridian and increases with distance from it. This suits charts of long north-south strips.

Question 35Charts and Chart Projections: Properties, Uses and Limitations

A route is plotted on a gnomonic chart as a straight line. How is it normally transferred for practical flight navigation?

  1. By measuring the length on the gnomonic chart and flying that heading
  2. By plotting waypoints from the gnomonic chart onto a conformal chart and joining them Correct answer.
  3. By reading the track directly from the gnomonic graticule without correction
  4. By converting the straight line into a rhumb line on the same chart

Explanation

The gnomonic chart gives the great-circle path but is not conformal, so bearings cannot be measured directly. The usual practice is to mark positions along the great circle and transfer them to a conformal chart, where tracks and distances can be measured. The route is then flown as a series of short legs.

Question 36Charts and Chart Projections: Properties, Uses and Limitations

What is the purpose of the standard parallels on a Lambert conformal conic chart?

  1. They mark the lines along which chart scale is exactly correct Correct answer.
  2. They indicate where great circles become straight lines
  3. They show the boundary between chart sheets
  4. They mark the limits of magnetic variation

Explanation

On a conic projection the cone cuts or touches the sphere along the standard parallels, where scale is exactly correct. Between them scale is slightly too small and outside them slightly too large. Choosing standard parallels wisely keeps scale error small over the charted area.

Question 37Charts and Chart Projections: Properties, Uses and Limitations

On a Lambert conformal conic chart, a great circle between two points in the northern hemisphere appears as a curve. How is it curved?

  1. Concave toward the equator
  2. As a straight line at all times
  3. Convex toward the pole
  4. Concave toward the pole Correct answer.

Explanation

In the northern hemisphere the great circle between two points lies closer to the pole than the rhumb line joining them. On a conic chart this makes the great circle appear as a curve concave toward the pole. The rhumb line between the same points lies nearer the equator on the chart.

Question 38Charts and Chart Projections: Properties, Uses and Limitations

A chart states that it uses a scale of 1:250 000 at 30 degrees north, with the scale increasing away from that parallel. Which projection is most consistent with this description?

  1. Lambert conformal conic with a standard parallel at 30 degrees north Correct answer.
  2. Ordinary Mercator with the equator as the line of true scale
  3. Polar stereographic
  4. Gnomonic

Explanation

A conic projection has a standard parallel where scale is exactly correct, with scale error growing away from it. A Lambert conformal conic with a standard parallel at 30 degrees north fits the description precisely. Mercator would have its true scale at the equator, not at 30 degrees north.

Question 39Charts and Chart Projections: Properties, Uses and Limitations

Why does a rhumb line appear as a straight line on a Mercator chart while a great circle does not?

  1. Because Mercator is a perspective projection from the centre of the Earth
  2. Because the poles are shown as points on Mercator
  3. Because Mercator is equal-area, so all lines are straight
  4. Because meridians are parallel, so a constant-angle track plots as a straight line Correct answer.

Explanation

A rhumb line crosses every meridian at the same angle. Since Mercator draws meridians as parallel straight lines, a line cutting them at a constant angle is itself straight on the chart. A great circle changes its angle to the meridians, so it plots as a curve.

Question 40Charts and Chart Projections: Properties, Uses and Limitations

A pilot uses a chart on which the scale is correct only along the standard parallel, and away from that parallel the scale increases in both directions. What effect does this have on a straight-line plot made well away from the standard parallel?

  1. The plotted bearings will be reversed because meridians converge away from the standard parallel
  2. The plotted distances will be overstated because the chart scale is larger than the true scale there Correct answer.
  3. The plotted distances will be understated because the chart scale is larger than the true scale there
  4. The plotted distances remain exactly correct because scale is constant over the whole chart

Explanation

When the chart scale is larger than the true scale in a region, one unit of chart measurement represents a smaller true distance than the scale statement suggests, so distances measured from the chart come out larger than reality. The error grows with distance from the standard parallel, where the scale is exactly correct. Bearings are not reversed by scale enlargement; only the meridian convergence pattern affects direction.

Question 41Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

An aircraft's true heading is 090° and the true wind is from 360° at 20 kt. The aircraft's true airspeed is 120 kt. What is the wind angle relative to the aircraft's nose?

  1. 90° from the right
  2. 30° from the right
  3. 90° from the left
  4. 30° from the left Correct answer.

Explanation

The wind direction is where the wind blows from, so a wind from 360° blows toward 180°. The nose points to 090°, so the wind vector crosses the flight path at 90° to the nose; the wind comes from 90° to the left of the nose, giving a wind angle of 30° off the nose on the left side.

Question 42Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

True track is 045°, true heading is 060°, and true airspeed is 100 kt. What is the drift angle?

  1. 30° to the left
  2. 15° to the right Correct answer.
  3. 15° to the left
  4. 45° to the right

Explanation

Drift is the angle between heading and track. Here the heading is greater than the track, meaning the aircraft is pointed right of the track, so the wind has pushed it left and the track lies to the left of the nose. The drift is therefore 15° to the right in the sense of heading minus track.

Question 43Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

An aircraft flies with true heading 270° and true airspeed 150 kt. The wind is from 180° at 30 kt. What is the true track?

  1. 300°
  2. 276°
  3. 270° Correct answer.
  4. 264°

Explanation

A wind from 180° blows toward 360°, so it is a pure tailwind along a westerly heading. A pure headwind or tailwind component does not produce drift, so the track equals the heading and remains 270°.

Question 44Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

Which statement correctly describes groundspeed?

  1. Groundspeed is true airspeed multiplied by the cosine of the drift angle
  2. Groundspeed is the speed indicated on the airspeed indicator
  3. Groundspeed is true airspeed corrected for drift only
  4. Groundspeed is the aircraft's speed over the ground, equal to true airspeed plus or minus the wind component along track Correct answer.

Explanation

Groundspeed is the velocity of the aircraft relative to the ground. It equals true airspeed combined with the headwind or tailwind component along the track, so a tailwind increases it and a headwind reduces it.

Question 45Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

The wind is from 090° at 25 kt and the aircraft's true heading is 090° with true airspeed 125 kt. What is the groundspeed?

  1. 100 kt Correct answer.
  2. 25 kt
  3. 125 kt
  4. 150 kt

Explanation

With a heading of 090° the aircraft flies toward the east, while a wind from 090° blows toward the west. This is a direct headwind, so groundspeed is true airspeed minus wind speed, which gives 100 kt.

Question 46Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

An aircraft's true heading is 000° and true track is 010°. The drift is described as:

  1. 10° to the right Correct answer.
  2. 10° of headwind
  3. 10° of tailwind
  4. 10° to the left

Explanation

Drift is the angle between the nose and the track. With heading 000° and track 010°, the track lies to the right of the nose, so the aircraft is drifting right. The magnitude is the 10° difference.

Question 47Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

The wind is from 270° at 30 kt and the aircraft's true heading is 270° with true airspeed 130 kt. What is the groundspeed?

  1. 30 kt
  2. 160 kt Correct answer.
  3. 100 kt
  4. 130 kt

Explanation

A wind from 270° blows toward 090°. The aircraft heading 270° flies toward the west, so the wind is a direct tailwind. Groundspeed is 130 kt plus 30 kt, giving 160 kt.

Question 48Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

Which wind is a pure crosswind for an aircraft tracking 360°?

  1. Wind from 360°
  2. Wind from 045°
  3. Wind from 090° Correct answer.
  4. Wind from 180°

Explanation

A pure crosswind is perpendicular to the flight path. For a track of 360° the crosswind must blow from 090° or 270°, at right angles to the track, so a wind from 090° is purely across the path.

Question 49Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

An aircraft has true heading 030°, true track 045°, and true airspeed 140 kt. What is the groundspeed?

  1. About 145 kt
  2. 140 kt
  3. About 120 kt
  4. About 135 kt Correct answer.

Explanation

The wind triangle shows that when drift is present, the along-track component of the true airspeed is TAS times the cosine of the drift angle. The cosine of 15° is about 0.966, so the along-track airspeed is about 135 kt. The groundspeed must be less than TAS when a crosswind component is present because part of the airspeed is used to counter drift.

Question 50Dead Reckoning Navigation: Track, Heading, Wind, Drift and Groundspeed

The wind is from 315° at 40 kt and the aircraft's true heading is 360° with true airspeed 160 kt. What is the crosswind component from the right?

  1. About 14 kt
  2. About 20 kt
  3. About 28 kt Correct answer.
  4. About 40 kt

Explanation

The wind angle is the difference between heading 360° and wind direction 315°, which is 45°. The crosswind component equals wind speed times the sine of the wind angle, so 40 kt times sine 45° gives about 28 kt. Since the wind comes from the left of the nose, it pushes the aircraft to the right.