I've been playing x-plane a lot, and I have an odd question.
Right now, for example, I am flying LGA-SXM. My Indicated Air Speed is 297 knots. There is a 21 knot wind at 170, and yet my ground speed is 461 knots. My TAS, which I don't know what it stands for, is 482 knots.
How are GS and TAS related to IAS and how are they calculated? I always thought GS was the sum (or, in this case, with a head-wind, the difference) of IAS and wind speed, but apparently that's wrong.
On a related note, if my IAS is 297 at 33000 feet, why is my Mach number .82, where as at sea level at the same IAS, the Mach number would be much less? I understand it has to do with air pressure and temperature and the like, but I'm confused as to WHY all that makes a difference.