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View Full Version : TAT to SAT Conversion

05-21-2014, 08:18 AM
I briefly looked around this forum on the subject, but I failed to find anything. I am currently working on some performance charts for the 135 outfit I fly Citations for and I am having a difficult time finding any easy to use formula for converting TAT to SAT for climb performance. I've spent a few hours searching for it using various media, but have been at a loss. Any input will help, a simple chart or anything would be of great use.

05-21-2014, 09:47 AM
Calculating ram rise? [Archive] - PPRuNe Forums (

Some good info there, such as:

Another rule of thumb that we used was
TAT= SAT + (TAS/100)^2.
It works pretty well for approximation.

True enough, an approximation. If you want the exact figure with Knots TAS as the entry variable -

TAT= SAT + (TAS/87.1)^2, which is exact :ok:

Or, if your entry variable is Mach Number -

TAT= SAT + (1+.2*M^2), which is also exact :ok:

Prop operators may prefer the former, jet jockeys the latter.

05-21-2014, 07:20 PM
is another WAG.

galaxy flyer
05-24-2014, 12:22 PM
Use whichever Cessna uses which is probably RAT or TAT, no need for converting them.