Airbus Unplugged
A quick query as you have me confused; I hope I do not confuse you with the first paragraph of my query due to the wording
Our Mode S shows the
IAS that you have selected. Obviously as you slow down with inertia, the IAS in our Mode S will tick down til it gets to the required setting (much the same way as when we tell you to fly a heading.... you select the heading but our mode S follows your compass round until it hits the requested heading).
I was of the opinion that a gust of wind as you mentioned would not change the IAS reading, it merely changes your True Air Speed and ground speed, therefore, we can tell if you are at 160 by 4 dme because that is what your IAS readout should say. If you are established at 160kts and you experience a 20kt gust, does this cause the IAS to change??
Surely if that is the case, then when we ask you to do a set speed when you are farther out i.e. 290kts surely your mode S readout would show us what you were doing with regards to the wind i.e. if you had a 50kt tail wind, it would show up on our radar as speed of 340kts.
Just wondering really, because this does not happen with mode S.. we can see what (IAS) speed you are flying at that point in time (or radar update point), as well as the ground speed, which is the resolution of IAS to TAS to GS. Wind variations do not show up on the IAS part of our mode S readout.