The aircraft initially flies south, so it flies along the meridian 004°11'E. Along a meridian "1 minute of latitude equals to 1 NM". Thus, a distance of 500 NM along a meridian corresponds to 500' change of latitude or 8° 20'.

Therefore, as it flies south on the northern hemisphere, its latitude will decrease, provided that it does not cross the Equator. Its new latitude at B point, after 500 NM south off A point, will be: 

• 26°06'N - 8° 20' = 17°46'N.

After B point, the aircraft continues eastwards (i.e. along the same parallel of latitude) for 500 NM along the 17°46'N parallel of latitude. The distance along a parallel of latitude is called "Departure" and is given by the formula: 

• Departure(NM) = Change of Longitude(min) x cos Lat.

Solving for Change of Longitude we get: 

• Change of Longitude(min) = Departure(NM) / cos Lat = 500 NM / cos 17°46' = 525 or 8° 45'.

Therefore, its new longitude, after 500 NM east off B point, will be: 

• 004°11' + 8° 45' = 012°56' E.

Finally, C position's coordinates will be: 17°46'N 012°56' E.