Consumption

[Flybiker7000]

It came suddently to me today: How big is the consumption for take-off and climb to flight-level - compared to the following levelled flight?
Regarding a typically modern airliner, it is.

[Green Guard]

Cruise fuel / dist equals roughly (T/O Climb to ToC plus from ToD to Landing) fuel / per that distance.

[Flybiker7000]

Take-off and climb are (almost!?) equalled by the decending in the other end! Sadly I must admit that I never have given this logic a thought before now :-(

However, the consumption of the T/O and climb alone (wich would be most understandable as comparished with the cruise consumption) would be interesting to hear!

[Intruder]

We seldom look at the fuel flow during takeoff. However, a bit of research indicates the specific fuel consumption of a GE CF6 is .354 (lb/hr fuel consumption per lb thrust) at sea level (Exergy Analysis of a Turbofan Engine: CF6-80 (PDF Download Available) (http://www.researchgate.net/publication/228422319_Exergy_Analysis_of_a_Turbofan_Engine_CF6-80)). At a nominal 60,000 lb thrust, that would mean a fuel flow of about 9600 Kg/hr. Nominal cruise thrust in a 747-400 is 2500-3000 Kg/hr per engine, depending on weight and altitude. At idle, they burn 500-600 Kg/hr.

[Meikleour]

A319 at typical weights uses ~ 1,800kgs to top of climb ( mid to upper 30s ) in about 25 minutes. The descent typically takes 30 minutes and uses ~ 600 kgs.

The cruise uses about 2,000kgs/hour.

This "rule of thumb" is pretty accurate in my experience as a gross check on the computer flight plan.