Commercial jet aircraft fly at cruising altitudes between 30

Solution

Air for pressurization is taken from the compressor. As far as outside temperature is concerned, a standard atmospheric day starts off at 15 degree celsius at 0 feet MSL. The temperature cools at the rate of 1.5 degree celsius with each one thousand feet of altitude all the way up until reaching the tropo pause. The efficiency of an internal combustion engine is directly proportional to the temperature difference of the hot sink and cold sink. In this case the hot sink is the combustion chamber and the cold sink is the outside air. this is one of the reasons why it is more efficient to fly higher. Further more at any constant fan or compressor RPM, a specific ratio of fuel to air must be introduced into the combustion chamber. the higher the air plane is the less air there is and as such, the less the amount of fuel that must be sequenced into the combustion chamber.