Nav Exam 1 Flashcards
What is air navigation
The art and science of safely navigating an ACFT from one place to another and determining it’s position at any time.
What are the essential questions of air navigation
Where am I? where am I going? When will I arrive at my destination? How will we get there?
The shape of the earth is?
Oblate spheroid
Shape of Earth for Navigation purposes
Perfect sphere
Define true poles
The extremities of the diameter about which the earth rotates
Define magnetic poles
The extremities of which the diameter indicated by a north seeking magnet
Define a great circle
A line on the surface of the earth with a centre and radius the same as the Earth
Define a small circle
A line on the earths surface with a radius and centre not the same as the earths
Define the equator
A great circle that is perpendicular to the axis of rotation and equal distance from both poles
What are meridians
semi great circles that join the poles
What are lines of latitude
Small circles that are parallel to the equator
What is a rhumb line
A regularly curved line that cuts through all meridians at the same angle
What occurs when a curved surface is represented on a flat surface
Distortion
What are 4 properties of an ideal map
Constant scale, adjacent maps can be places next to each other, con-formality, equal areas, rhumb lines as straight lines, great circles are straight lines
List 3 properties of con-formality
Scale expansion/contraction from any point is independent of azimuth/direction. Shape on the chart conforms to the area being portrayed. Meridians and parallels cut at right angles
List 4 properties of a Mercator projection
- great circle is curved convex to the pole
- scale is constant only at the standard parallel
- bearings are correct
- rhumb line is straight
- the equator and meridians are the only great circles with straight lines
Limits of the Mercator projection
- can’t depict poles
- must apply conversion angles to great circle tracks
- distortion of large shapes
- large distance difficult to measure
- limited to 70N-70S
4 properties of a lamberts conformal projection
- great circles are straight lines
- has 2 standard parallels
- scale considered consistent
- conformal
Care must be takes when plotting on a lamberts chart due to:
Lines of longitude convergence
2 methods of expressing scale of a chart
Fraction, statement or geographically
Is 1 : 500 000 or 1 : 1 000 000 a smaller scale chart?
1 : 1 000 000
Would 1:250 000 or 1 : 500 000 cover a smaller areas with a same sized map
1 : 250 000
List 2 of the 4 major properties of an aviation map or chart
Lattitidude/ longitude grid
Elevation in feet
Mercator or lamberts projection
Centrally controlled
Charts used for high level instrument flying
ERC H, ONC
