shape speed direction Flashcards
what is the shape of the earth?
oblate spheroid
what way does earth rotate?
west to east. (counterclockwise if viewed above)
what is the tilt of the earth?
23.5 degrees
where is the equator?
line drawn in the middle of earth
what is the polar axis?
runs from the geographic north pole (true north) to the geographic south pole
what is magnetic poles?
poles which arent situated at the exact north and south geographic poles, with dotted lines between the poles being the magnetic flux.
angular difference between true north and where your compass points is called what?
variation
what are the meridians of longitude?
lines running from geographic north to south pole
what are parallels of latitude?
lines running horizontally around the world
what is the latitude of the equator?
0 degrees
what is a great circle ?
a circle that when drawn on a sphere passes through the centre of that sphere. cuts it in half.
every meridian of longitude and its opposite half on the other side of the world are known as what? and what is the opposite half?
great circle, anti meridian
what is a small circle?
any other circle drawn on earth other than the equator.
what is a rhumb line?
a line crossing all meridians of longitude at the same angle which is a constant direction.
what is the Greenwich meridian or prime meridian?
zero point for longitude which is in Greenwich england. located 0 degrees east or west. where time measured in GMT is used as UTC
latitude is described in what typically?
degrees, minutes and seconds
what is the 360 degree method of indicating direction?
compass directions
what are the cardinal and intercardinal directions?
N,S,W,E (000, 180, 270, 90)
meridians of longitude run from what?
true north to true south
how is true direction measured?
difference between the path or track of the aircraft, and the merdian
e.g aircraft flying directly north (360). the angle between a meridian (always points north) and track is 35 degrees therefore 360 - 35 = 325 degrees T (True)
what is true north?
direction along Earth’s surface towards the geographic North Pole
what is magnetic north?
the direction in which the north end of a compass needle or other freely suspended magnet will point in response to the earth’s magnetic field.
It deviates from true north over time and from place to place because the earth’s magnetic poles are not fixed in relation to its axis.`
what is compass north?
direction in which a compass needle points
what is magnetic variation?
angular difference between true north and the lines of magnetic flux.
e.g if you were on this line and it was 22.5 degrees E, it will mean that the magnetic variation is 22.5 degrees east.
what is an isogonal?
lines joining places having the same variation,
what is magnetic direction?
the direction of the Magnetic North Pole from a place. or magnetic south
what is the NZ magnetic direction?
- 5 degrees near Paraparaumu.
- 5 degrees east at the very top
- 5 degrees at the very bottom near Stuart Island.
how is true direction converted into magnetic direction? and how is the reverse done?
using mnemonic variation east - magnetic least, variation west - magnetic best
e.g wanting to fly a true heading of 270, and variation is 23 degrees east, 270 - 23 = magnetic direction of 247.
current magnetic direction is 270 and variation is 23 degrees east, what is the true direction?
since variation east. magnetic is least ( true must mean most) therefore 270+ 23 = 293 degrees T
what is magnetic deviation?
deviation over time due to the earths magnetic field
what is compass deviation?
deviation, where the aircraft compass is affected by the characteristics of things like electrical circuits in close proximity and the influence of metal objects near the compass, may deviate it.
what causes magnetic dip?
over the equator, the force pulling down on each pole of the magnet is the same, but if we move away from the equator, say south, the south pole seeking end of the compass needle will be drawn downwards to the magnetic south pole.
In other words, the compass needle will have a dip towards the south. Closer you get to the south pole the greater the angle of dip.
what is deviation?
the angular difference between magnetic direction and compass direction
how is compass direction found?
deviation east - compass least
deviation west - compass best
if the magnetic direction is 54 degrees M and has a deviation error of 2degrees. what is the compass direction
54+2 = 56 degrees
what is a bearing?
an angle between one object and another
what is a true bearing?
when a line is drawn on a chart, the direction between the start and finish places can be expressed as true bearing.
can be defined as the angular difference from true north of a straight line drawn between two places.
what is a magnetic bearing?
the true bearing that can be calculated to express a magnetic bearing done by adding or subtracting variation.
e.g true bearing chch to Hokitika is 305degrees T, local isogonal indicates variation in region is 23 degree E therefore (305 - 23 = 282 degrees M)
what is a compass bearing?
magnetic bearing that has been accounted for deviation.
e.g true bearing from rotorua to hamilton of 287degree T and has isogonal of 20degreeE (287 - 20) = 267M
compass variation of 2degree W (267 + 2 = 269degree C)
what is relative bearing?
the number of degrees of another object from the heading of an aircraft.
what is relative bearing using the clock method?
using relative bearing but converting a 360-degree compass to a 12 o’clock clock.
what is a nautical mile?
based on the circumference of the earth and is equal to 1 minute of latitude (1/60th of a degree of latitude).
it is equal to 1852m or 1.85km
what is a statute mile?
imperial system unit for distance. 5,280ft long.
what is a foot?
imperial unit for 12 inches
what is a metre?
base unit in the metric system, define by how far light travels in a vacuum in part of a second. equal to 100cm or 39.37 inches
what is a km?
unit in the metric system. 1000m
1NM = how many km and statute miles?
- 85km
1. 15 statute miles
1KM = how many nm and statute miles?
0.54 miles and 0.62 statute miles
1 statute mile = how many nm and km?
0.87nm and 1.6km
what is a knot?
unit of speed equivalent to 1 nm per hour (1.852km/hr)
what is IAS?
the airspeed read directly from the airspeed indicator on an aircraft, driven by the pitot-static system
what is calibrated airspeed?
indicated airspeed corrected for instrument and position error
what is true airspeed?
the actual speed we are travelling through the air
what is ground speed?
Ground speed is the horizontal speed of an aircraft relative to the Earth’s surface. vital for navigation.
what is the difference between speed and velocity?
speed is a scalar meaning it only has a magnitude whereas velocity is a vector meaning it has a magnitude and a direction.
e.g reported win is 235/10 meaning wind is coming from 235 degrees at a speed of 10 kts.
