Jet Aircraft Fuel Burn Variations with Altitude
Hi everybody,
Was wondering if anybody would be able to help me with my query, it's part of a university assignment I am currently trying to complete.
For a typical jet aircraft, for instance the Boeing 737-400, why do aircraft not fly at relatively low cruise altitudes?
As far as I understand a jet engine works more efficiently at higher altitudes, also as fuel payload is burnt off throughout the flight the optimum altitude can be increased (met by conducting step altitudes).
However, is there any factors that would cause fuel burn at lower altitude to be lower in comparison to high altitude (excluding the effects of jetstreams). I was hoping the effects of Specific Air Range may factor into it but if anyone could help that would be greatly appreciated.
Regards,
Dan