Could someone please give me a chart that shows mach? or if not that, what would N0476 and N0470 be in mach terms? thanks.adam

No table for you, but here is the formula to calculate:c = 331.6 + 0.6(t/T) m/sc is the speed of sound in airt is the temperature of the airT is the absolute temperature of the air which is constant at 273The Mach number can be derived at as M = v/c where v is your speed and c is the speed of sound.speed of sound is largely independent of pressure, which might surprise a few people but highly dependent on temperature (as you can see in the above formula.1 knot is about 1900 kmh. 1 m/s is 3.6 kmh.This makes one knot roughly 527.75 m/sSo M = 527.75v/((331.6 + 0.6(t/T))) in knots.

Hi,I have a similar but different method as that we are using in our JAA ATPL studies.LSS = Local Speed of SoundLSS (at any altitude) = 38.94 * sqr(T) where "38.94" is a constant and "T" is the temprature at that altitude in degrees Kelvin. So FL290 would be approx 231 Kelvin in ISA conditions.Mach No can be derived by two methods:1) Mach = (Pitot Pressue - Static Pressure)/ Static Pressureor2) Mach = TAS/LSS.Again a slight difference in that LSS is completely independant of pressure (as seen with equation 1) and wholly dependant on temprature as seen with (equation 2)!>>1 knot is about 1900 kmh. 1 m/s is 3.6 kmh.>>This makes one knot roughly 527.75 m/sYou mean 1kt is 1.9kmh :)However, TAS is dependant on pressure and temprature. For a constant IAS (CAS) if you climb your TAS will increase. For a constant TAS and assuming temprature decreases with altitude your Mach will increase as the LSS reduces due to the drop in temprature.Therefore it is not possible to say what is the Mach for a TAS, only what is the Mach for a TAS and temprature or for a CAS (IAS), FL and temprature.Does that help or confuse things?Kef.P.S. The bane of the ATPL students life but answers all (well nearly) questions, the CRP-5 (http://www.transair.co.uk/xtrapics/crp5.htm)