In our earlier lesson we had learnt about ISA and ISA Lapse Rate. Now let us understand a little bit about Jet Standard Atmosphere. JSA VS ISA Similar to ISA which has been defined for aircraft and instruments another definition has been made for high level flights and spacecraft testing. Although most of the definitions are same there are some variations between JSA and ISA. In JSA air is considered to be dry and mean sea level its temperature is +15 degrees centigrade just like that of ISA. The mean…
Author: Wg Cdr Rajagopal
Ground Instructor for Pilots as well as a Qualified Career Adviser. The author has served as Flight Navigator as well as a Personality Assessor in Airforce.
ISA Lapse Rate
In our earlier lesson, we had seen that as per the definition of International Standard Atmosphere, the Mean Sea Level temperature is +15 degrees centigrade. In this post, let us understand the lapse rate of temperature as per ISA Conditions. ISA TROPOSPHERE – TROPOPAUSE As per ISA conditions, we have defined that the temperature decreases at a constant rate of 1.98 degrees Celsius per 1000 feet, or by 0.65 degrees Celsius per 100 meters. The temperature continues to reduce down to minus 56.5 degrees Celsius at 11 kilometres above the…
International Standard Atmosphere
In this post, we shall understand about the need and details of International Standard Atmosphere which is also referred as ISA Conditions or ISO Conditions. Earlier we had understood about all the layers in the atmosphere including the Ionosphere which has a large amount of free Ions. ISA OR ISO CONDITIONS Most of our flying and our weather is contained within the first two layers of the atmosphere, namely the troposphere and the stratosphere. Within these two layers we have many properties which are important to us like density, pressure…