NAV 02 - The Earth Flashcards
What is Air Navigation?
“The are of directing an aircraft from one position to another, and of determining the position of the aircraft over the earth at any point”
Or
Finding out where you are, where you should be, and how to match the two.
What shape is the earth? What are some characteristics of it’s shape?
Oblate Spheroid
A symmetrical body with a ‘bulge’ in one axis (think Stewie’s head)
What is the Equatorial and Polar radii?
Equatorial = 6378 Km Polar = 6356 Km (22 Km smaller)
What is a Great Circle? What is it’s significance WRT distance?
A circle on the surface of the earth whos center and radius are those of the sphere itself.
It divides a sphere into two equal parts
Shortest distance on Earth’s surface between two points
Describe the Equator
Great circle on the earth which is perpendicular to the Earth’s axis of rotation.
What is a Small Circle?
A circle on the surface of the earth whose center and radius are NOT those of the sphere itself
(All circles on the earth that are not Great Circles are Small Circles
What is a Parallel?
A small circle on Earth’s surface whose plane is parallel to the equator.
How is a Parallel (Latitude) measured?
It is the angular distance from the equator, measured along a meridian. UOM are degrees, minutes and seconds
Define Meridian
A semi-great circle on the surface of the Earth joining the poles of the Earth.
All meridians converge at the poles.
How is a Meridian (Longitude) measured?
It is the angular distance from the prime meridian, measures along the shorter arc of the equator
Units are degrees, minutes, seconds
Where is the Prime Meridian located?
Greenwich
What is a Rhumb Line? What are some of its benefits WRT aviation?
It is a regularly curved line on the surface of the Earth cutting all meridians at the same angle.
A Rhumb line is used to allow a path of flight to be a straight line on some maps (ie Mercator maps)
When flying a Rhumb line, the heading remains constant whereas flying a great circle, constant heading changes are needed
1 NM equals how many feet and degrees of latitude change?
6080 feet and 1’ of Lat
How many SM and Km are in 66 NM?
76 SM & 122 Km
Review Questions
What is a Great Circle?
A circle on the surface of the Earth whose center and radius are those of the sphere itself. Also the shortest distance between two points.
