Fuel consumption question
Hi,
could someone please explain in detail why fuel consumption is lower at higher altitudes at CONSTANT IAS if we consider constant fuel/air ratio 1:15? Eg to comapre FL160 and FL 240, the exact numbers don't really matter.
We were discussing that with a few of my classmates and a couple of airline pilots even but nobody could exactly describe all the phenomenons that affect this obvious fact, since we discount TAS.