# How is mach speed calculated?

Yesterday, I flew at FL500 with a Cessna citation:

Why my IAS is very low (my engines are at the maximum) and why, when I decend after that, I can decend at 6000ft/min without spoilers??!
If my aircraft don’t recive air, how mach is calculated?

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overspeeding x) the engines aren’t at 0 :p

Object speed divided by the speed of sound.
Mach has nothing to do with KIAS. The air on those altitudes are so high, using KIAS would be impractical, because you can’t reach the IAS you normally would cruise on at that altitude.

Basically, Mach 1 is the speed of sound. Mach 0.72 is 72% of the speed of sound. In the same way, mach 1.2 is 120% of the speed of sound… :)

This is gas theory. I’m not that experienced in that field, but from what I’ve learned, that is how it’s calculated.

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Thank you :D (that’s theorie sound good)

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Also, the speed of sound isn’t constant, unlike the speed of light. It depends on the altitude, air pressure and temperature, amongst other things.

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Please search and or Google. Not trying to be mean, it’s good advice that will get you far in life!

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It’s more fun to search’s more fun to make a topic than search on Google but… anyway, Thank you

. (Aero Science)

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THX bra :)

First pic is to hard for me xc

@Q-ENAN… MAXSez: Me to. Trigonometry was never my strong suit. I use the Graf type above from the aircraft QRG or the Flight Management System my Swiss friend. Great question. Regards

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Speed of light is constant, which is why it is called ‘c’ (constant) in the famous theory E=mc^2
I think…

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Whops! Typo there I see… I meant to say UNlike… :) So people don’t confuse speed of sound to be constant, like the speed of light…

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@Q-ENAN. Failure to research and take the ez route is a sign of “Sloth”.
Do it now at your age and somebody will be carrying your water for the rest of yr life! PS: Sloth is not a Swiss Trait. Sham on you!

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ayyy who dars calling me ?

;D

nope xD sorry :p