Can't give you an exact or precise indication as where to find the information you are seeking suffice to say that the two
seperate meteorology guides I used to get my UK ATPL (A) both mention JSA.
Manual 1 states the following:
Jet Standard Atmosphere
The mean sea level values of temperature, pressure and density are identical to those of the ISA, however the temperature lapse rate is assumed to be 2 degrees Celsius per 1000ft with no tropopause. In other words, the temperature in the JSA at 40000ft is -65 degrees
Celsius (as compared with -56.5 degrees
Celsius in the ISA)
Manual 2 states this:
There is also a Jet Standard Atmosphere which is ISA made easy for pilots. Here the temperature lapse rate is assumed to be 2 degrees Celsius per thousand feet
with no tropopause.
You will meet the JSA in Flight Planning;it is not used in
meteorology.
To back up the above claim I encountered the JSA in my Flight Planning examination when presented with CAA publication Data Sheets 33 and 34 (
ahh happy memories
) relating to the '
specimen aircraft' remarkably similar to the VC10 and B747.
Having obtained a FAA ATP the year before my UK ATPL (A), I cannot recall hearing or seeing any reference to JSA in my FAA study notes; maybe a reason you
haven't come across the term is because you don't get examined the way we were in the UK in the early 90's
