by Brett_Henderson » Sun Jun 10, 2007 12:46 pm
I don't fly the jets often, but when I do, I like to keep fuel on board to a minimum, so a selected altitude is important.
All weather and wind being equal, and allowing 7 miles per 3000 feet on the descent (climbs are steeper); you'd need 70nm to get down from 30,000 feet (allowing for further descent in a pattern).
From that reference, not wanting a descent to be more than 1/4 of the flight; you'd need to be facing a 280nm flight MINIMUM for a 30,000msl cruise. Round that up to 300nm and that's a good reference point.
Looking at that ratio ( 300nm for 30,000msl ) you get 1:100
100nm = 10,000 cruise (prob why 737s don't take flights that short very often)
200nm = 20,000 cruise (I've been on a 737 that took that flight)
300nm = 30,000 cruise (seems reasonable)
and a 400nm minimum for 40,000 cruise (can they even fly that high ?)
Most any flight longer than 300nm would end up with a cruise altitude between 30,000 and 40,000.
The higher the better for fuel economy, but obviously climbing up to 30,000 and then having to descend immediately isn't very efficient..lol
Last edited by
Brett_Henderson on Sun Jun 10, 2007 12:50 pm, edited 1 time in total.
