ATPL GENERAL NAVIGATION EXAM
QUESTIONS AND ANSWERS
Convergency Formula - Correct Answers -= Change in Long x Sin (mean lat)
Departure Formula - Correct Answers -= Change in Long x Cos (mean lat)
What shape is the Earth? - Correct Answers -Oblate spheroid or ellipsoid
What is a Rhumb line? - Correct Answers -A line which crosses each meridian at a
constant angle, so has a constant track. Includes parallels of latitude.
What is a Great circle? - Correct Answers -The largest possible circle around the Earth
whose centre passes through the centre of the Earth - includes all meridians and the
equator.
The track (relative path angle to north) along a great circle is constantly changing when
not moving along a meridian or the equator.
The equator can be what type(s) of lines? - Correct Answers -A rhumb line and a great
circle
In which directions do the meridians point? - Correct Answers -Northward. They diverge
at the South Pole and converge at the North Pole.
What is the circumference of the Earth? - Correct Answers -40,000 km or 21,600 nm
Radius of Earth (Average) - Correct Answers -6366 km or 3437 nm
Radius of the Earth at the equator - Correct Answers -6,378 km or 3440 nm
Radius of the Earth at the Poles - Correct Answers -6357 km or 3430 nm
Semi major radius & semi minor radius conversion - Correct Answers -Semi-major to
semi-minor = / 1.0033
Semi-minor to semi-major = x 1.0033
Geocentric Latitude - Correct Answers -The angle between a line drawn from a point on
the surface to the Earth's centre and the plane of the Equator.
, Geodetic/Geographic Latitude - Correct Answers -The angle between a perpendicular
line drawn from a point on the Earth's surface and the equator.
Due to the oblate spheroid shape of the Earth, the line will pass near, but generally not
through the centre of the Earth.
The latitude where the greatest difference between geodetic and geocentric occurs and
the error in minutes of arc. - Correct Answers -45° North/South, 11.6 minutes of arc.
1 nautical mile = ? kilometres - Correct Answers -1.852
1 nautical mile = ? feet - Correct Answers -6080
1 nautical mile = ? statute miles - Correct Answers -1.15
1 kilometre = ? feet - Correct Answers -3280
1 meter = ? feet - Correct Answers -3.28
1 minute of arc latitude in nautical mile - Correct Answers -1 nmi
Also equals 1nmi along the equator's longitude but gets shorter towards the poles.
(Departure equation)
3 chart projections - Correct Answers -Direct Mercator - cylindrical
Lamberts - conical
Azimuthal or plane (stereographic)
Where on a direct Mercator chart is the chart orthomorphic? - Correct Answers -The
chart is orthomorphic close to the equator.
Is the lamberts conical chart orthomorphic? - Correct Answers -The chart is very
Nnearly orthomorphic.
Is the polar stereographic chart orthomorphic? - Correct Answers -That chart is very
nearly orthomorphic at the poles.
Where is the scale correct on a direct Mercator chart? - Correct Answers -The scale is
correct at the Equator or parallel of origin.
Where is the scale correct on a lamberts conical chart? - Correct Answers -The scale is
correct at the standard parallels.
Where is the scale correct on a polar stereographic chart and where does it change? -
Correct Answers -The scale is correct at the poles, but expands outwards.
QUESTIONS AND ANSWERS
Convergency Formula - Correct Answers -= Change in Long x Sin (mean lat)
Departure Formula - Correct Answers -= Change in Long x Cos (mean lat)
What shape is the Earth? - Correct Answers -Oblate spheroid or ellipsoid
What is a Rhumb line? - Correct Answers -A line which crosses each meridian at a
constant angle, so has a constant track. Includes parallels of latitude.
What is a Great circle? - Correct Answers -The largest possible circle around the Earth
whose centre passes through the centre of the Earth - includes all meridians and the
equator.
The track (relative path angle to north) along a great circle is constantly changing when
not moving along a meridian or the equator.
The equator can be what type(s) of lines? - Correct Answers -A rhumb line and a great
circle
In which directions do the meridians point? - Correct Answers -Northward. They diverge
at the South Pole and converge at the North Pole.
What is the circumference of the Earth? - Correct Answers -40,000 km or 21,600 nm
Radius of Earth (Average) - Correct Answers -6366 km or 3437 nm
Radius of the Earth at the equator - Correct Answers -6,378 km or 3440 nm
Radius of the Earth at the Poles - Correct Answers -6357 km or 3430 nm
Semi major radius & semi minor radius conversion - Correct Answers -Semi-major to
semi-minor = / 1.0033
Semi-minor to semi-major = x 1.0033
Geocentric Latitude - Correct Answers -The angle between a line drawn from a point on
the surface to the Earth's centre and the plane of the Equator.
, Geodetic/Geographic Latitude - Correct Answers -The angle between a perpendicular
line drawn from a point on the Earth's surface and the equator.
Due to the oblate spheroid shape of the Earth, the line will pass near, but generally not
through the centre of the Earth.
The latitude where the greatest difference between geodetic and geocentric occurs and
the error in minutes of arc. - Correct Answers -45° North/South, 11.6 minutes of arc.
1 nautical mile = ? kilometres - Correct Answers -1.852
1 nautical mile = ? feet - Correct Answers -6080
1 nautical mile = ? statute miles - Correct Answers -1.15
1 kilometre = ? feet - Correct Answers -3280
1 meter = ? feet - Correct Answers -3.28
1 minute of arc latitude in nautical mile - Correct Answers -1 nmi
Also equals 1nmi along the equator's longitude but gets shorter towards the poles.
(Departure equation)
3 chart projections - Correct Answers -Direct Mercator - cylindrical
Lamberts - conical
Azimuthal or plane (stereographic)
Where on a direct Mercator chart is the chart orthomorphic? - Correct Answers -The
chart is orthomorphic close to the equator.
Is the lamberts conical chart orthomorphic? - Correct Answers -The chart is very
Nnearly orthomorphic.
Is the polar stereographic chart orthomorphic? - Correct Answers -That chart is very
nearly orthomorphic at the poles.
Where is the scale correct on a direct Mercator chart? - Correct Answers -The scale is
correct at the Equator or parallel of origin.
Where is the scale correct on a lamberts conical chart? - Correct Answers -The scale is
correct at the standard parallels.
Where is the scale correct on a polar stereographic chart and where does it change? -
Correct Answers -The scale is correct at the poles, but expands outwards.
