Abu Dhabi to Sydney, 09 June 13, Airbus A340-600, registration A6 EHJ, the one with the F1 livery.
On the ground still, using the camera to see the body and the wheels, to ensure the plane is on the hard surface all the time, not on the grass..
In the air, the True Air Speed, TAS indicating 481, 481 knots or 481 nautical miles per hour. Roughly 890 km per hour. The GS is the ground speed, 539 knots, around 998 km per hour. So which one is the actual speed actually?
TAS is the speed of the plane piercing through the air at that particular atmosphere or piece of air, another word, the speed of the plane in relation to that piece of air at that particular moment..
GS is the speed of the plane in relation to the surface of the earth or ground, measurement of how much the plane covered in one hour over the ground, in Nautical Miles, kts. Why the value between TAS and GS
Here, the TAS is 474 and the GS is 580.
There are another numbers, 269/108 below the TAS and GS. This is the wind vector, bearing , or direction of the wind coming from 269 deg on the compass at the speed of 269 knots.Since the plane's heading is at 095 deg, the wind direction is coming from behind the plane, as indicated by the small arrow below the numbers.It means, the wind is pushing the plane from behind at the speed of 108 knots. The pane already travelling through the air at the speed of 474 knots, and now the wind help to push it from behind at roughly 106 kts ( not 108 because the wind direction is not exactly from behind, slightly offset) giving the total speed the plane
travelling over the surface of the Earth at 580 knots.
The result will be the opposite if the plane is flying the other way round, the GS should be 474-106, 368 knots. This is why the flight time of a particular flight always varies, not the same all the time. It is depending either the plane is subjected to tailwind or the headwind.. not because the pilot fly purposely flying faster or slower...