Nav Flashcards
What is Nav
The art and science of safely and efficiently directing an aircraft from one place to another, and
determining the aircraft’s position at any time.
Problem of air Nav is
Where are we
Where are we going
How will we get there
When will we get there
The shape of the earth is:
oblate spheroid, bulged at the equator
The shape of the earth for nav is
Perfect Sphere
True poles
The extremities of the diameter about which the earth rotates.
Magnetic poles
The extremities of the diameter indicated by a north seeking magnet.
Great circles?
A line on the surface of the earth with a centre and radius the same as the earth.
Small circles
A line on the surface of the earth with a centre & radius NOT the same as the earth.
Equator
A great circle which is perpendicular tho the axis of rotation and equidistant from both poles.
Meridian lines
Semi-great circles that join the poles.
Parallels of Latitude
Small circles that are parallel to the equator.
Rhumb lines
A regularly curved line that cuts all meridians at a constant angle.
What problem when the earth is represented on a flat map
Distortion
Ideal map
Any 4 of:/conformality, constant scale, equal area, great circles are straight lines, rhumb lines as
straight lines, adjacent maps fit together, geographic position easily located.
Properties of conformity
Scale expansion/contraction from any point is independent of azimuth/direction.
Shape on the chart conforms with the area being portrayed, and Meridians and parallels cut at right angles
12.
List four 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 which are straight lines
List four limitations of a Mercator Projection.
13.
Any four of:
Can’t depict poles
Must apply conversion angles to great circle tracks Distortion of large shapes
Large distances difficult to measure.
limited to 70N - 70S
Rhumb Lines are straight lines
Great circle is curved convex to the pole
List four properties of a Lamberts Conformal projection.
Great circles are straight lines
Rhumb lines are curved concave to the nearest pole
Has 2 standard parallels
Scale considered constant
Conformal, ie bearings and shapes are correct.
Maps fit E-W if the same standard parallels are used on each map.
Why must care be taken on plotting on lambert chart
b
lines of longitude convergence
C.
methods of expressing the scale of a chart.
Fraction (1:100 000),
Statement (inch to one mile),
Graphically
List 2 of the four major properties of an aviation map or chart.
latitude/longitude grid,
elevation in feet,
mercator or lamberts projection,
centrally controlled.
charts used for high level instrument flight are:
ERC(H), ONC
The charts used for low level visual flight are:
ERC(L), VNC
Which of the following has one grid of latitude and longitude
ERC (L)
Which of the following has two grids, latitude/longitude and transverse mercator grid.
TPC
Which of the following has two grids, latitude/longitude and transverse mercator grid. (2 Runways with a circle around it
Aerodrome minor
