Aproximately how many perecent the true altitude will be lower than your indicated altitude , if the temperture is 10°C colder than standard ?
It's not a linear deviation so it depends on the altitude and the temperature at that altitude. The deviation gets worse as you go higher and colder.
Lower and warmer, the error for 10 deg is very small, but higher and colder it can be a couple hundred feet.
Everybody uses a standard table that you can find all over the place with Google. See here on Page 33 of the General Section of the Canada Air Pilot CAP GEN (IFR approach plates for Canada) which explains how to apply the corrections, and can also be found in the AIM. They are only used for IFR use for correcting altitudes for instrument procedures when close to the ground, and are generally not applied unless the temperature at the airport is below freezing.
$\begingroup$ Thanks I couldn't get the image post to work and I just realized it was because I didn't convert it to jpeg. $\endgroup$– John KJan 2, 2019 at 22:08
$\begingroup$ Thanks for answering so what is 4% temperture corection for -10° $\endgroup$ Jan 4, 2019 at 8:54
$\begingroup$ And also i found this formula in some other pages ................ 4 ft for 1 degree of deviation from ISA for every 1000 ft , then 4x10 / 1000 = 4% $\endgroup$ Jan 4, 2019 at 8:55