There you go again (yawn). Never made the claim you wrote above and never used the specific numbers (or any) with regard to that alleged claim. Used the word "perhaps" in answering the OP's question which is a word of speculation, and not claim.

I posted two good articles articles for you to read (one using the very google search terms you suggested) to educate yourself on airline cooling systems and that despite the frigid outdoor temps at cruising altitude, airline cabins actually do need to be cooled. You erroneously believed that critical thinking meant the opposite. The articles I found for you proved the opposite. Perhaps you can provide some articles to back your, thus far proven erroneous assertions up?

I just don't find the assertions you made in your previous post credible unless backed up by a source other than yourself.

I'm asking a really simple question here. Based on all your research, and you advanced degrees from google university, do you believe that it causes measurable fuel burn difference to set the cabin to 73 degrees F instead of 75 degrees F?

Well what do your "critical thinking" skills tell you the answer is? Once you answer that then I suggest you click on the links to the three articles I posted on this thread and try to deduce for yourself the answer to your newly posed question and compare/contrast it with your "critical thinking" thought.

I assure you the factual answer to your question is in at least one of the articles. I won't do your homework for you. =)

So in other words you refuse to answer what you think. I understand completely why you would.

Guys, calm down. The air from outside is compressed (pressurization, remember)? This heats it, so it is cooled by the heat exchangers in the A/C packs. Cabin staff can change a thermostat, which does not turn on or off the A/C, but slightly modifies the mixing of hot compressed air with cooled compressed air.

No significance to fuel burn. Flying 5 knots slower would be a much better way to save fuel.

Great find! Thanks for sharing.

I do not agree with the assertion that there would be no significance in fuel burn. The significance can be minute or it can be much greater depending on the a/c type, and distance flown.

For a short regional flight on a highly efficient a/c the significance may be extremely minute, however on a long haul flight on an inefficent 767 or 744 the significance is much more measurable to the profit or loss of that flight, particularly in light of high jet fuel prices.

The article below, which link I am re-posting, strongly suggests that the significance may be greater than perceived.

http://www.nytimes.com/2004/09/03/st...trqa_ed3_.html

Broken link for me

If you go up to hnussbacher's post, the link there to the same article should work.

I suppose on the pilots worksheet there is a line for him to enter the cabin temperature he intends to set during his flight, right? How else can he calculate how much fuel to load!