Navigation Flashcards
What is the shape of the Earth?
Oblate spheroid
What is the diameter of the Earth?
12,742 km
What is latitude?
The measure of position relative to the equator (horizontal)
What is longitude?
The measure of position relative to the prime meridian (vertical)
What is a great circle?
The largest possible circle that can be drawn around a sphere.
The centre of a great circle is in the centre of the sphere.
If you were to cut the earth along a great circle you would cut it in half.
Where do all meridians converge?
The North Geographic Pole (True North) and South Geographic Pole
What is Magnetic North?
A region near the North Geographic Pole from which magnetic flux lines emanate.
Simple magnetic compasses orient to magnetic north.
What is the angular variation between the North Magnetic Pole (Magnetic North) and the North Geographic Pole (True North) known as?
Magnetic variance.
True or False. Regardless of an aircraft’s position, magnetic variance is always the same.
False.
Magnetic variance will differ depending on an aircraft’s location.
Lines of magnetic variance are depicted on aeronautical charts.
What factors must a pilot account for in simple navigation?
- Magnetic variation
- Wind
Will the magnetic direction be less (i.e. a smaller angle) than the equivalent true direction when the Magnetic Variation in the region of a flight is depicted as ‘degrees west’?
No.
Magnetic direction will be less than True direction when the magnetic variation is depicted as degrees EAST.
Converting True Direction to Magnetic Direction can be made easy with the phrase “Variation East, Magnetic Least”.
What is relative bearing?
The angular difference of a position with reference to the heading (or nose) of the aircraft.
Explain the three types of airspeed.
Indicated Air Speed (IAS): the speed that the pilot sees in the cockpit on their airspeed indicator. This is calibrated to standard atmospheric conditions.
True Air Speed (TAS): the actual speed that the aircraft is travelling through the air. This value will be different to IAS because of air density and also, as with any mechanical device, there may be small inaccuracies due to the aircraft’s equipment.
Ground Air Speed (G/S): will help the pilot determine how
long it is going to take from their departure point to their destination which will then help them calculate how much fuel they will need. The difference between TAS and G/S is wind.
What is a mach number?
A ratio obtained by dividing the TAS of an aircraft by the Local Speed of Sound (LSoS)
Define Sunrise
When the top of the sun appears above the horizon
Define Sunset
When the sun dips below the horizon
What is the period between sunrise or sunset and the sun being 6 degrees below the horizon known as?
Morning and Evening Civil Twilight