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Circle whos radius is that of the earth and whose plane passes through the centre of the earth.
the shorter arc is the shortest distance between any two points
Any circle on the surface whose radius is not that of the earth.
A regular curved line which cuts all
at the same angle
The extremities of the spin axis of the earth
Where all meridians meet
Parallel of Latitude
All Small Circles (other than equator)
All Rhumb Lines
Also known as Greenwich Meridian
Semi-Great circle passing through the poles and through
Defines Longitude 0
East or West
Lies at 180
degrees removed east/west from the Meridian in question
Prime Anti-meridian is at exactly 180 east/west of Greenwich
Kind of follows 180 meridian
X Y grid formed by the meridian, equator and parallels of lattitude
Difference between true direction and Magnetic direction
Variation is east when Mag north lies East of True North
Variation is west when Mag north lies West of True North
Lines joining points of equal Variation
A/C specific error in compass.
Compass Swing performed
Compass direction +/- deviation gives magnetic direction
Deviation is east when Compass north lies East of Mag North
Deviation is west when Compass north lies East of Mag North
Does 1 degree of longitude equal 60 miles?
Only at the equator. Always true for latitude though.
Distance = d Long x Cos lat
Only valid for points at the same
Earth Convergence Formula
The angle of inclination between any two meridians at a given Latitude.
Change of Long(deg) x sin
How does Wind effect distance to PNR and ETP?
ETP always moves into the wind.
PNR reduces in any wind compared to Nil wind conditions
What Fuel Profile gives the PNR furtherest away
Best Range Speed
How does Air Density affect TAS
TAS will increase with lower density
Increase in height, or an increase in ambient temp and same height.
What Grid referencing system is used for GNSS and FMS
World Geodesic system 1984
"Geod" meaning the earth shape
when using departure formula to get Distance between two points on same parallel is the answer a Rhumb Line or great circle
What is the conversion angle
Difference between the Rhumb line track and the true track at the start and end of the lines.
Equal to half the earth convergence.
= 0.5 x d.long sin mean latitude