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CPL Navigation (Sri Lanka CAA Pilot Licence Examinations) practice questions

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Question 1Navigation

On a Lambert conformal conic chart used for navigation in Australia, what is the principal property that makes it suitable for plotting radio bearings over long distances?

  1. Areas are preserved exactly so wind drift can be measured directly
  2. Rhumb lines plot as straight lines and the scale increases uniformly away from the standard parallels
  3. Great circles plot as approximately straight lines and the scale is nearly constant across the sheet Correct answer.
  4. Bearings measured anywhere on the chart equal true bearings without correction

Explanation

The Lambert conformal conic is conformal, so angles are preserved, and a straight line on the chart closely approximates a great circle. This makes it convenient for plotting long-range radio bearings and tracks. Scale is nearly constant within the standard parallels, which supports accurate distance measurement.

Question 2Navigation

An aircraft is tracking along a meridian in the Southern Hemisphere with a constant heading and no wind. How does the true track compare with the true heading?

  1. Track is greater than heading because the aircraft must turn to maintain the great circle
  2. Track equals heading because meridians are great circles Correct answer.
  3. Track is less than heading because of easterly convergence
  4. Track and heading diverge only if the aircraft crosses the equator

Explanation

A meridian is part of a great circle, so an aircraft flying along it with no wind follows that great circle exactly. With no wind, heading and track are identical. Convergence of meridians does not change this, because the aircraft is not crossing meridians.

Question 3Navigation

The variation at a position is 12°E and the aircraft's magnetic heading is 045°M. What is the true heading?

  1. 033°T
  2. 213°T
  3. 045°T
  4. 057°T Correct answer.

Explanation

Easterly variation is added when converting from magnetic to true: true = magnetic + easterly variation. Here 045° + 12° = 057°T. Remember the mnemonic that easterly variation is added going from magnetic to true.

Question 4Navigation

An aircraft is heading 090°M with 15° of westerly variation. What is the magnetic bearing of a station that lies directly ahead on the aircraft's centreline?

  1. 270°M
  2. 090°M Correct answer.
  3. 105°M
  4. 075°M

Explanation

If the station is directly ahead, its relative bearing is 000° and the magnetic bearing equals the magnetic heading. Variation affects the conversion between true and magnetic, not the magnetic bearing itself. The answer is therefore 090°M.

Question 5Navigation

What is the standard formula for calculating the time in minutes to fly from one waypoint to the next?

  1. Groundspeed divided by distance, multiplied by 60
  2. Distance divided by 60, multiplied by groundspeed
  3. Distance divided by groundspeed, multiplied by 60 Correct answer.
  4. Distance multiplied by groundspeed, divided by 60

Explanation

Time equals distance divided by speed; multiplying by 60 converts hours to minutes. For example, 120 NM at 180 kt gives 0.667 h, or 40 minutes. Groundspeed must be used, not indicated or true airspeed.

Question 6Navigation

An aircraft flies a track of 090°T at a true airspeed of 120 kt. The wind is 180°T at 30 kt. What is the approximate groundspeed?

  1. 150 kt
  2. 116 kt Correct answer.
  3. 124 kt
  4. 90 kt

Explanation

The wind is almost a direct crosswind, so only a small component acts along track. The along-track component is 30 × cos 90°, which is zero, but the drift means the aircraft must crab, reducing groundspeed slightly. The resultant is approximately 116 kt after resolving the triangle of velocities.

Question 7Navigation

An aircraft has a true heading of 270°T and a magnetic variation of 10°W. What is the magnetic heading?

  1. 260°M
  2. 090°M
  3. 280°M Correct answer.
  4. 250°M

Explanation

Westerly variation is added when converting from true to magnetic: magnetic = true + westerly variation. Here 270° + 10° = 280°M. The mnemonic is that westerly variation is added going from true to magnetic.

Question 8Navigation

What is the purpose of the drift angle in a navigation flight log?

  1. To record the difference between true heading and magnetic heading
  2. To convert indicated airspeed into true airspeed
  3. To express the angular difference between heading and track caused by wind Correct answer.
  4. To measure the angle between the aircraft nose and the horizon

Explanation

Drift is the angle between the aircraft's heading (where the nose points) and its track over the ground. It arises because wind pushes the aircraft sideways, so the pilot must crab to maintain the desired track. Drift is applied in the opposite direction to the wind.

Question 9Navigation

An aircraft is 30 NM from a VOR/DME station and its OBS is set to the station's radial of 270°. On which side of the selected course does the aircraft lie if the CDI shows a full-scale deflection to the right?

  1. South of the 270° radial
  2. Directly on the 270° radial
  3. North of the 270° radial Correct answer.
  4. East of the station beyond the cone of confusion

Explanation

With the OBS set to the 270° radial, the selected course runs east-west. A right deflection means the aircraft is to the right of the course when facing the station along the selected direction. Facing west along the 270° radial, right is north, so the aircraft lies north of the radial.

Question 10Navigation

An aircraft flies from a point at 30°S 150°E to a point at 30°S 160°E along the parallel of latitude. Approximately how far does it travel?

  1. 540 NM
  2. 520 NM Correct answer.
  3. 470 NM
  4. 600 NM

Explanation

Along a parallel, distance equals change of longitude in minutes multiplied by the cosine of the latitude. Ten degrees is 600 minutes of longitude, and cos 30° is about 0.866, giving roughly 520 NM. This is shorter than the great-circle distance between the same points.

Question 11Navigation

What does the term 'convergence' mean when applied to a navigation chart?

  1. The tendency of the aircraft to drift towards the inside of a turn
  2. The increase in scale towards the chart edges
  3. The rate at which the distance between meridians decreases towards the poles Correct answer.
  4. The angle between true north and magnetic north

Explanation

Meridians converge towards the poles, so the spacing between them decreases with increasing latitude. Convergence is expressed as the angle between two meridians at a given latitude. Grid convergence is the angle between grid north and true north at a point.

Question 12Navigation

On a Mercator chart, a straight line drawn between two points represents which of the following?

  1. A great circle
  2. A rhumb line Correct answer.
  3. A line of constant magnetic bearing
  4. A small circle of constant latitude

Explanation

On a Mercator projection, meridians are parallel straight lines and parallels are straight lines, so a constant-angle course plots as a straight line. That is a rhumb line, not a great circle. Great circles appear as curved lines on a Mercator chart.

Question 13Navigation

An aircraft at 40°N 060°W wishes to reach 40°N 020°W. What is the approximate rhumb-line distance along the parallel?

  1. 1,200 NM
  2. 2,400 NM
  3. 1,600 NM
  4. 1,836 NM Correct answer.

Explanation

The change of longitude is 40°, or 2,400 minutes. Along the parallel, distance equals minutes of longitude multiplied by cos 40°, and cos 40° is about 0.766. This gives approximately 1,836 NM.

Question 14Navigation

What is indicated when the DME readout shows 0 NM but the VOR needle is still usable?

  1. The aircraft is beyond the service volume of the station
  2. The aircraft is directly over the station, where DME reads zero Correct answer.
  3. The DME has failed and the reading should be ignored
  4. The DME is displaying slant range and the aircraft is at the cone of confusion

Explanation

DME measures slant range, and directly overhead the station the horizontal distance is zero, so the readout approaches zero. The VOR may still give a bearing until the aircraft enters the cone of confusion. Slant-range error is largest at high altitude and close range.

Question 15Navigation

An aircraft is flying a track of 030°T with a wind from 330°T at 40 kt and a true airspeed of 160 kt. Which effect does the wind have on the heading?

  1. The heading must be decreased to counteract drift to the left
  2. The heading is unaffected because the wind is a crosswind
  3. The heading must be increased to counteract drift to the right Correct answer.
  4. The heading must be increased because the wind is a tailwind

Explanation

The wind from 330°T blows towards 150°T, which is to the right of the 030°T track. To hold the track, the aircraft must point left of track, so the heading is reduced below 030°T. The drift is to the right, and the correction is to the left.

Question 16Navigation

What is the significance of the 'standard parallels' on a conic projection?

  1. They are the latitudes where magnetic variation is zero
  2. They define the equator and the poles
  3. They are the latitudes where the scale is exactly correct Correct answer.
  4. They mark the limits of the chart's usable area

Explanation

On a conic projection, the cone touches or cuts the globe at the standard parallels. Along these latitudes the scale is exactly correct, and scale error grows with distance from them. Choosing standard parallels close to the area of use minimises distortion.

Question 17Navigation

An aircraft departs at 0230 UTC and the planned flight time is 3 hours 45 minutes. What is the estimated time of arrival in UTC?

  1. 0615 UTC Correct answer.
  2. 0545 UTC
  3. 0515 UTC
  4. 0615 local time

Explanation

Adding 3 hours 45 minutes to 0230 gives 0615 UTC. Times in flight planning are normally expressed in UTC to avoid time-zone confusion. The answer must be stated in the same time reference as the departure.

Question 18Navigation

An aircraft flies a true heading of 120°T with 8°E variation and 4°E deviation. What is the compass heading?

  1. 116°C
  2. 108°C Correct answer.
  3. 124°C
  4. 132°C

Explanation

From true to compass, subtract easterly variation and then subtract easterly deviation: 120° − 8° = 112°M, then 112° − 4° = 108°C. Both easterly errors are subtracted when converting from true to compass. The reverse conversion adds them.

Question 19Navigation

An aircraft maintains a constant heading of 090°T in still air in the Southern Hemisphere. What happens to its true track as it flies east?

  1. It remains 090°T because a constant heading gives a constant track
  2. It gradually turns towards the north as the great circle curves
  3. It gradually turns towards the south as the great circle curves Correct answer.
  4. It oscillates around 090°T due to magnetic variation

Explanation

A constant heading traces a rhumb line, which crosses each meridian at the same angle. The great circle from the same point curves poleward relative to the rhumb line, so in the Southern Hemisphere the track moves south of 090°T. In the Northern Hemisphere the equivalent track would move north.

Question 20Navigation

A flight plan requires 480 NM at a groundspeed of 180 kt. Fuel burn is 40 kg per hour. How much fuel is required for the leg, excluding reserves?

  1. 160 kg
  2. 120 kg
  3. 107 kg Correct answer.
  4. 90 kg

Explanation

Time equals 480 divided by 180, which is 2.667 hours. Multiplying by the burn rate of 40 kg per hour gives about 107 kg. The calculation uses groundspeed, not airspeed, because fuel is consumed over time in the air.

Question 21Navigation

An aircraft is tracking a great circle from 20°S 120°E to 20°S 060°E. At the midpoint, how does the great-circle track compare with the rhumb-line track?

  1. The two tracks coincide along the whole route
  2. The great-circle track runs closer to the equator than the rhumb line
  3. The great-circle track runs closer to the pole than the rhumb line Correct answer.
  4. The great-circle track is longer than the rhumb line

Explanation

A great circle between two points in the same hemisphere bulges poleward relative to the rhumb line. In the Southern Hemisphere the great circle therefore reaches higher southern latitudes at the midpoint. The great-circle distance is always shorter than the rhumb-line distance.

Question 22Navigation

What is the effect of using a chart with a scale of 1:500,000 rather than 1:1,000,000 for the same area?

  1. The chart shows more detail and a smaller area per sheet Correct answer.
  2. The chart has a larger scale error than the smaller-scale chart
  3. The chart removes the need for variation correction
  4. The chart covers twice the ground area per sheet

Explanation

A scale of 1:500,000 is larger than 1:1,000,000, meaning one unit on the chart represents fewer units on the ground. Larger-scale charts therefore show more detail but cover less ground per sheet. Scale does not affect the need for variation correction.

Question 23Navigation

Which of the following best describes the term 'grid convergence' as used in grid navigation?

  1. The angle between grid north and true north at a given position Correct answer.
  2. The angle between the aircraft's heading and its track
  3. The angle between true north and magnetic north at a given position
  4. The rate at which DME slant range changes with altitude

Explanation

Grid north is a reference direction chosen for a grid overlay, and it differs from true north except along the reference meridian. The angle between grid north and true north at a point is grid convergence. It must be applied when converting between grid and true bearings.

Question 24Navigation

An aircraft flies a constant magnetic heading in an area where variation changes along the route. What happens to the true track?

  1. It changes only if the aircraft crosses the magnetic equator
  2. It is unaffected by variation but changes with deviation
  3. It remains constant because magnetic heading is constant
  4. It changes as the variation changes, even with a constant magnetic heading Correct answer.

Explanation

True heading equals magnetic heading plus or minus variation, so if variation changes along the route, the true heading and hence the true track change. This is why long flights are planned in true directions and converted for each leg. A constant magnetic heading does not guarantee a constant true track.

Question 25Navigation

An aircraft at 10,000 ft is directly over a DME station. What does the DME read, and why?

  1. Zero, because the horizontal distance is zero
  2. Approximately 10 NM, because DME reads altitude in thousands of feet
  3. Zero, because DME only operates below 5,000 ft
  4. Approximately 1.6 NM, because slant range equals altitude Correct answer.

Explanation

DME measures slant range, so directly overhead the reading equals the aircraft's height above the station. At 10,000 ft that is about 1.6 NM, since 6,076 ft equals one nautical mile. The reading falls towards zero only as altitude above the station approaches zero.

Question 26Navigation

On a Lambert conformal conic chart, what is the practical effect of the projection being conformal?

  1. Distances are true along every meridian
  2. Angles measured on the chart equal the corresponding angles on the Earth Correct answer.
  3. Great circles plot as straight lines anywhere on the sheet
  4. Areas are preserved exactly at every latitude

Explanation

A conformal projection preserves angular relationships, so a bearing measured on the chart corresponds to the true angular relationship on the Earth's surface. This is why conic charts suit radio-navigation plotting, where bearings are drawn directly. Area and scale distortion still exist away from the standard parallels.

Question 27Navigation

A chart carries the statement 'scale 1:250,000'. What does this mean for a measured chart distance of 4 cm?

  1. It represents 10 km on the ground Correct answer.
  2. It represents 1 km on the ground
  3. It represents 100 km on the ground
  4. It represents 62.5 km on the ground

Explanation

A representative fraction of 1:250,000 means one unit on the chart equals 250,000 of the same units on the ground. Four centimetres therefore represents 4 x 250,000 = 1,000,000 cm, which is 10 km. The same ratio holds whatever unit is used.

Question 28Navigation

In Southern Hemisphere temperate latitudes, what is the general behaviour of a low-pressure system that a pilot should anticipate when planning a route?

  1. Air circulates anticlockwise around it, with winds veering as it passes
  2. Air flows directly from the centre outwards with no rotation
  3. Air circulates clockwise around it, with winds veering as it passes
  4. Air circulates clockwise around it, with winds backing as it passes Correct answer.

Explanation

In the Southern Hemisphere the Coriolis effect deflects moving air to the left, so air circulates clockwise around a low. As a low approaches and passes, wind direction typically backs, and pressure falls then rises. This matters for drift and for choosing alternates.

Question 29Navigation

An aircraft is cleared to hold at a VOR over a fix, and the pilot wishes to enter the holding pattern. Which statement describes a standard holding pattern?

  1. Left-hand turns with one-minute inbound legs at or below 14,000 ft
  2. Right-hand turns with one-minute inbound legs at or below 14,000 ft Correct answer.
  3. Right-hand turns with two-minute inbound legs at all levels
  4. Left-hand turns with two-minute inbound legs at all levels

Explanation

A standard hold uses right-hand turns, and the inbound leg is timed at one minute at or below 14,000 ft, extending to one and a half minutes above that level. Non-standard holds are notified explicitly. Entry procedure depends on the aircraft's heading relative to the holding fix.

Question 30Navigation

What is the purpose of a flight log in pre-flight navigation planning?

  1. To record planned headings, times, fuel and actual in-flight progress leg by leg Correct answer.
  2. To provide the ATC clearance in written form for the pilot
  3. To certify the aircraft's maintenance release before departure
  4. To list the aircraft's weight and balance limitations

Explanation

The navigation flight log is the working document where each leg's planned heading, groundspeed, time and fuel are entered and then updated with actuals in flight. It allows the pilot to compare planned and actual progress and revise estimates. It is not an airworthiness or clearance document.

Question 31Navigation

An aircraft's altimeter is set to the standard pressure setting and reads 12,000 ft. What does this value represent?

  1. Density altitude
  2. Pressure altitude Correct answer.
  3. Height above the aerodrome
  4. True altitude above mean sea level

Explanation

With 1013.2 hPa set, the altimeter indicates pressure altitude, the altitude above the 1013.2 hPa datum. True altitude above mean sea level requires the local QNH, and height above the aerodrome requires QFE. Density altitude additionally accounts for temperature.

Question 32Navigation

Which of the following is the definition of magnetic variation?

  1. The angle between true north and magnetic north at a given place Correct answer.
  2. The angular difference between heading and track
  3. The error caused by the aircraft's electrical systems
  4. The angle between magnetic north and compass north on a particular aircraft

Explanation

Variation is the angle between true north and magnetic north at a location, and it changes with position and slowly with time. Deviation, by contrast, is the aircraft-specific error between magnetic and compass north. Confusing the two is a common source of heading errors.

Question 33Navigation

An aircraft is flying along a magnetic track of 045°M with 3°W deviation. What compass heading should be flown to maintain this track in still air?

  1. 051°C
  2. 048°C Correct answer.
  3. 045°C
  4. 042°C

Explanation

In still air, compass heading equals magnetic heading adjusted for deviation. With 3°W deviation, compass reads less than magnetic, so the pilot must steer 3° more on the compass: 045 + 3 = 048°C. Remember the mnemonic that west deviation means compass north lies west of magnetic north.

Question 34Navigation

On a direct Mercator chart, how does the spacing of the meridians behave?

  1. Meridians are curved lines that meet at the pole
  2. Meridians converge towards the poles
  3. Meridians are equally spaced parallel straight lines Correct answer.
  4. Meridian spacing increases with latitude

Explanation

The Mercator projection is constructed so that meridians appear as equally spaced straight parallel lines and parallels as straight lines whose spacing increases towards the poles. This makes it a useful plotting chart, although scale expands with latitude. The meridian spacing does not vary.

Question 35Navigation

An aircraft flies a rhumb line between two points on the same parallel of latitude in the Northern Hemisphere. Which statement describes the track along this rhumb line?

  1. The track is constant and the path lies equatorward of the great circle Correct answer.
  2. The track is constant and the path coincides with the great circle
  3. The track is constant but the path curves poleward of the great circle
  4. The track changes continuously along the route

Explanation

A rhumb line crosses every meridian at the same angle, so its track is constant, but it is not the shortest path except along a meridian or the equator. Between points on a parallel in the Northern Hemisphere the great circle bulges poleward, so the rhumb line lies equatorward of the great-circle arc.

Question 36Navigation

An aircraft at 30°S 000°E flies due west along the parallel to 30°S 030°W. Approximately what distance has it covered?

  1. 2,080 NM
  2. 1,560 NM Correct answer.
  3. 900 NM
  4. 1,800 NM

Explanation

The change of longitude is 30°, and at latitude 30° one degree of longitude equals 60 x cos 30° = 51.96 NM. Multiplying by 30 gives about 1,559 NM, so 1,560 NM is the correct figure. Departure must always be corrected for latitude in this way.

Question 37Navigation

An aircraft is tracking towards a VOR with the CDI centred and the OBS set to the inbound radial. The aircraft then drifts to the right of the selected course. What does the CDI show?

  1. The needle deflects left, and the aircraft is right of course Correct answer.
  2. The needle deflects right, and the aircraft is left of course
  3. The needle deflects right, and the aircraft is right of course
  4. The needle deflects left, and the aircraft is left of course

Explanation

With the OBS set to the inbound radial, the CDI indicates the position of the aircraft relative to the selected course in the sense of the course arrow. If the aircraft is right of the inbound course, the needle deflects left, telling the pilot to fly left to regain the centreline. The TO/FROM indicator remains FROM when tracking inbound.

Question 38Navigation

An aircraft flies a true heading of 090°T at TAS 140 kt. The wind is 180°T at 40 kt. What is the resulting drift angle?

  1. Approximately 8° left
  2. Approximately 16° right
  3. Approximately 16° left Correct answer.
  4. Approximately 30° right

Explanation

The wind is a pure crosswind component of 40 kt from the south, while the aircraft's forward motion is 140 kt. The drift angle satisfies sin(drift) = 40/140 = 0.286, giving about 16.6°. Because the wind pushes the aircraft towards the north, the track lies to the left of the heading, so the drift is left.

Question 39Navigation

An aircraft's DME indicates 60 NM slant range while the aircraft is at 12,000 ft. Approximately what is the ground distance to the station?

  1. About 58 NM
  2. About 60 NM
  3. About 59 NM Correct answer.
  4. About 50 NM

Explanation

Slant range exceeds ground range because of the aircraft's height. Converting 12,000 ft gives about 2 NM, and the ground distance is the square root of (60² - 2²), which is approximately 59.97 NM, rounding to about 59 NM. The error is small at long range but significant close to the station.

Question 40Navigation

What is the primary advantage of a Lambert conformal conic chart for radio navigation plotting over a Mercator chart at high latitudes?

  1. Bearings and great circles are represented with less angular distortion across the chart Correct answer.
  2. It eliminates the need to apply magnetic variation
  3. It provides a constant scale everywhere on the chart
  4. It shows the whole globe on a single sheet

Explanation

Because the conic projection is conformal and its standard parallels are chosen for the area of use, angular distortion is small and great circles are close to straight lines. This makes it convenient for plotting radio bearings and tracks over a continent. Scale still varies, but only slightly within the chart's latitude band.

Question 41Navigation

An aircraft flies from 45°N 010°W to 45°N 020°E. What is the approximate rhumb-line distance along the parallel?

  1. 900 NM
  2. 636 NM
  3. 1,270 NM Correct answer.
  4. 1,800 NM

Explanation

The longitude change is 30°, and at 45°N one degree of longitude is 60 x cos 45° = 42.43 NM. Multiplying by 30 gives about 1,273 NM. This is the departure along the parallel, which is the rhumb-line distance for a pure east-west leg.

Question 42Navigation

An aircraft is on a magnetic heading of 000°M and the pilot observes that the magnetic compass indicates a turn to the east. In the Northern Hemisphere, which turning error is being demonstrated?

  1. Deviation caused by the aircraft's electrical systems
  2. Acceleration error causing a false turn indication on easterly headings
  3. Turning error causing an apparent turn towards the east when accelerating through north Correct answer.
  4. Pivot error caused by the compass card sticking

Explanation

In the Northern Hemisphere the compass is affected by turning error, which is most pronounced on northerly and southerly headings. When turning through north the compass under-reads, giving the appearance of a turn in the opposite direction, and when turning through south it over-reads. Acceleration error, by contrast, is greatest on east and west headings.

Question 43Navigation

An aircraft is cleared to descend from FL 350 to FL 100 at a constant groundspeed of 420 kt and a rate of descent of 2,000 ft per minute. Approximately how many nautical miles of track will be covered during the descent?

  1. About 120 NM
  2. About 70 NM
  3. About 105 NM
  4. About 87 NM Correct answer.

Explanation

The descent is 25,000 ft at 2,000 ft per minute, so it takes 12.5 minutes. At 420 kt the aircraft covers 7 NM per minute, giving about 87.5 NM. This technique of dividing the rate of descent into the height change is the standard way to compute top of descent.

Question 44Navigation

What is the meaning of 'grid convergence' when used with a grid overlay on a polar stereographic chart?

  1. The rate at which the chart scale changes with latitude
  2. The angle between grid north and true north at a given position Correct answer.
  3. The angle between the aircraft's heading and track
  4. The angle between magnetic north and grid north

Explanation

Grid convergence is the angular difference between grid north, which is a fixed reference direction on the grid overlay, and true north at the aircraft's position. It depends on longitude relative to the grid datum meridian. It is used to convert between true and grid directions when working in grid navigation.

Question 45Navigation

An aircraft flies a constant true heading of 090°T with a steady wind from 000°T. How does the true track compare with the heading?

  1. The track is exactly 180°T because the wind is from the north
  2. The track equals 090°T because the wind is a pure headwind
  3. The track is less than 090°T because the wind pushes the aircraft north
  4. The track is greater than 090°T because the wind pushes the aircraft south Correct answer.

Explanation

A wind from 000°T blows towards the south, so it pushes the aircraft to the right of its heading when tracking east. The resulting true track is therefore greater than 090°T, and the drift is to the right. The crosswind component determines the size of the drift angle.

Question 46Navigation

An aircraft is flying at FL 180 with a true outside air temperature of -20°C. What is the approximate true altitude if the altimeter is set to 1013.2 hPa?

  1. About 16,200 ft
  2. About 17,600 ft Correct answer.
  3. About 18,400 ft
  4. About 18,000 ft

Explanation

True altitude differs from pressure altitude by roughly 4 ft per 1,000 ft for each degree Celsius of ISA deviation. At FL 180 the ISA temperature is about -20.7°C, so the deviation is small but slightly warm, giving a true altitude close to 17,600 ft after applying the correction. The exact value depends on the mean temperature of the column.

Question 47Navigation

An aircraft is tracking a great circle between two points in the Northern Hemisphere. How does the great-circle track compare with the rhumb-line track at the midpoint?

  1. The great-circle track is closer to the pole than the rhumb-line track Correct answer.
  2. The great-circle track is closer to the equator than the rhumb-line track
  3. The great-circle track crosses the equator at the midpoint
  4. The two tracks coincide at the midpoint

Explanation

In the Northern Hemisphere a great circle between two points curves poleward relative to the rhumb line, so at the midpoint it lies at a higher latitude. This is why great-circle routes save distance on long east-west flights. The rhumb line remains at a constant track angle.

Question 48Navigation

An aircraft at 60°N flies a rhumb line due east for 600 NM. Approximately what change of longitude results?

  1. 10°
  2. 30°
  3. 15°
  4. 20° Correct answer.

Explanation

At 60°N one degree of longitude equals 60 x cos 60° = 30 NM. Dividing 600 NM by 30 NM per degree gives 20° of longitude change. The cosine factor halves the departure compared with the equator, which is why high-latitude east-west legs cover large longitude changes.

Question 49Navigation

A pilot plans a flight from a point at 20°S 030°E to a point at 20°S 060°E. Which statement correctly describes the relationship between the rhumb-line and great-circle distances?

  1. The two distances are equal because both points share a latitude
  2. The great-circle distance is longer because it curves poleward
  3. The great-circle distance is shorter, and its track reaches a higher southern latitude at the midpoint Correct answer.
  4. The rhumb-line distance is shorter because it follows the parallel

Explanation

A great circle is the shortest path between two points on a sphere, so it is shorter than the rhumb line except along a meridian or the equator. In the Southern Hemisphere it bulges towards the South Pole, reaching a higher southern latitude at the midpoint. The rhumb line stays on the parallel.

Question 50Navigation

An aircraft is flying a constant magnetic heading in an area where magnetic variation changes from 5°W at the departure point to 12°W at the destination. What happens to the true track?

  1. The true track remains constant because the heading is constant
  2. The true track increases because the aircraft is effectively turning east relative to true north Correct answer.
  3. The true track oscillates because variation changes are random
  4. The true track decreases because the aircraft is effectively turning west relative to true north

Explanation

True heading equals magnetic heading plus easterly variation or minus westerly variation. If westerly variation increases along the route while the magnetic heading is held constant, the true heading increases, so the true track turns progressively east. Pilots must therefore adjust heading to maintain a constant true track.