It's pretty well known that High Bypass ratio engines are starved at cruise to feed air to the cabin. Primarily the very large ones(777, 767). The 777 and 767 have areas of the cabin in cruise that are suggested not to seat the old and very young because of several incidents of them passing out. The stews are told to watch people in those areas very closely. The 747 does not have this problem because it has 4 engines. From what I am told the 777 has the largest problem. I know they are working a fix to increase the circulation rate in the cabin. <img border="0" title="" alt="[Smile]" src="smile.gif" />