Well that is an issue with the MS ATC, which is a complete joke, it does not take into acount these kind of resrictions on aircraft.
It works, I imagine, by running a series of variables and mathematical calculations etc etc.
In the real world, ATC would not clear you up to FL420 that soon!
If you want realistic ATC however, I'd suggest either -
Vatsim - http://www.vatsim.net
IVAO - http://www.ivao.aero
Also at flight level 42000ft, my IAS could not reach 437/ 0.80 march (I set A/T to 0.. It remained at 385. Is that normal?
At a high flight level, the air is MUCH thinner than it is at sea level.
The IAS indicator on an aircraft works by measuring the speed of the air travelling through the pitot, which is a tube that intakes the outside air.
Because of the air being thinner at FL420, the IAS indication will not be acurate, purely because of the lack of air to measure.
So, the solution to this is TAS (True Air Speed) which is worked out based on a number of factors such as air density, static air temperature and the standard sea level temperature.
See http://en.wikipedia.org/wiki/True_airspeed for a more in depth explaination
Hope this helps 😉
Last edited by Matt (mattdean) on Sun Oct 29, 2006 4:31 pm, edited 1 time in total