ias is indicated airspeed right? if thats the case how are you only flying at 245kts but your ground speed is 580kts?
Indicated airspeed is the speed of the air going over the wings. You go higher, indicated goes down, because the air is thinner. You can see in the top right that we are doing .80 Mach. True airspeed is 455 + 134 tailwind = 589
The tailwind is slightly quartering so we are only getting 134 of it for a push. The other 6 knots is crosswind.
Indicated is what keeps the plane flying. Say the airplane stalls at 140 knots clean. That's based on IAS (indicated airspeed). As you go higher and higher, the indicated goes down, even though the airplane is moving through the air faster. As the indicated comes down, it moves closer to stall. This airplane has such a great wing that it's never a factor, but the Lear would back itself into what's called the coffin corner. The IAS would come down so low that it may only be 10-15 knots over stall, so you're flying it at its max Mach, so you can't go any faster, but if you slow down 15 knots, you stall. It's a fine line.
True airspeed (TAS) - the airspeed at which an airplane is moving relative to the air that surrounds it. Indicated airspeed corrected for non standard temperature and pressure.
Ground speed (GS) - the speed of the aircraft in relation to the ground.
Indicated airspeed (IAS) - the speed of an aircraft as shown on the airspeed indicator, calibrated to reflect standard atmospheric a diabetic compressible flow at sea level, incorrect end for airspeed system errors.