framer - 737-800 data - every 1000 lbs of weight decrease increases OPT/MAX altitude by 150'(most weights)
TOC fuel burn is 4500-5000 = OPT/MAX altitude increase of ~700'
I agree that it doesn't always increase as expected. It's been my experience from 17 yrs of observation that it doesn't always work as I explained, particularily with warm surface temperatures. In those cases altitude starts increasing with fuel burn about the time you reach cruise altitude which is what you've observed.
altitude increase per 1000 lb fuel burn (mid range weights) -
777 40'
763 70'
762 80'
757 100'
737 150'
Last edited by misd-agin; 15th Nov 2011 at 05:28.
Reason: added text