Fundamentals of Air Navigation Flashcards
What shape is the earth?
Oblate Spheroid
To what degrees is the earth’s axis inclined to its plane of rotation around the sun?
23.5 deg
What direction does the earth rotate?
Anti-clockwise
What is the graticule?
It is the grid formed by parallels of latitude and meridians of longitude.
What is the graticule measured in?
Degrees, minutes and seconds.
What latitude position is the equator at?
Zero latitude
What latitude position is the north pole at?
90 degrees North = North pole
90 degrees south = South pole
How is the latitude of a point on the earth’s surface calculated?
The angle of inclination between the Equator and the point on the earth’s surface.
What is the prime meridian of longitude?
Runs through the Royal Observatoy in Greenwich, England.
What are meridians east and west of the prime meridian named? How many are there?
- Meridian is either degrees east or west of the prime meridian.
- 180 to the east, 180 to the west.
What is the antemeridian of greenwish?
The 180 E meridian which is the same as the 180 W meridian.
How is the longitude of a place measured?
The angle between its meridian of longitude and the prime meridian, measured in E or W of the prime meridian.
What are the units of latitude and longitude?
Degrees, minutes and seconds.
How many NM are a degree?
60NM
How many nautical miles are one minute, expressed as ‘ ?
1 NM
How many metres are one second, expressed as “ ?
31 metres
What is A Great Circle (GC)? What does it represent?
- The largest circle that can be drawn on a sphere. Cutting it in two equal halves
- Its path represents the shortest distance between two points on the surface of the Earth
What are some examples of GCs?
- Meridians of longitude
- The equator.
How many GC can be drawn between two points on the earth?
Only 1, UNLESS the points are diametrically opposed, such as geographic poles
What is a Rhumb Line (RL)?
A curved line along the Earth’s surface that meets all meridians at the same angle.
What would a pilot have to do to fly a Rhumb Line?
Constant heading
When does a Rhumb line represent the shortest distance between two points?
Only if it is directly along the equator or a meridian of longitude –> It dollows a GC track
How does a GC track cross successive meridans? How will this effect the pilots heading?
At a gradually changing angle, will change the pilots heading.
Over what distances are the rhumb line and GC tracks the same?
Over short distances (<200 nm).
What is the usual unit of measurement for horizontal distances in aviation?
Nautical mile (NM)
What aviation purposes are the km or m used ?
- Visibility
- Horizontal distance from cloud
- Short distances
How many metres and feet is a nautical mile?
- 1852 m
- 6076 ft
What does a knot mean?
1 NM/hr
How many minutes of latitude is a NM?
1 minute
What is altitude measured in?
Feet above MSL or flight level in feet
What is height ?
Vertical distance of an object above a datum
What is elevation?
The vertical distance of a position above mean sea level
What is the arc time rate of rotation of the earth?
15 deg of longitude per hour
What are the three main datums for classifying time?
1) Local Mean Time (LMT)
2) Coordinated Universal Time (UTC)
3) Local Standard Time (LST)
What is Local Mean Time (LMT)?
- Uses the sun as its celestial reference point, and the local meridian of longitude as its terrestrial reference point.
- When sun is at its highest point in the sky, it is 1200.
What is Coordinated Universal Time (UTC)?
It is the local mean time at the meridian of longitude that runs through the Royal Observatory at Greenwich in London.
What is Local Standard Time (LST)?
- It is used to ensure that the population in a given region is using the same time datum as using LMT is not practical as it would different for every meridian of longitude.
- This give the world timezones.
What are the three Australian Time Zones and what are their UTC times?
1) AWST = UTC + 8
2) ACST = UTC + 10.5
3) AEST = UTC + 11
What is the International Date Line?
Is is an imaginary line of demarcation on the Earth’s surface that runs from the North Pole to the South Pole
- Travelling East, subject 1 day.
- Travelling west, add 1 day
When does sunlight occur between?
Sunrise = the upper edge of the sun rises above the eastern horizon Sunset = the upper edge of the sun descends below the west horizon
When is the beginning of morning civil twilight and what is it known as?
1) First Light
2) Begins when the centre of the sun is displaced 6 degrees below the eastern ideal horizon.
When does civil twilight end and what is it known as?
1) Last light
3) Ends when the centre of hte sun is displaced 6 deg below the western horizon
When is the period of daylight between?
First light and last light
