Aviator_69
17th Dec 2007, 10:04
Does anyone know if airlines adjust the CG when allocating seats and storing
baggage to minimise fuel burn? Since the tailplane has to provide a downward
force to balance the CG/CoP coupe, which to the wing is exactly the same as
carrying that amount of additional weight, by moving the CG forward could
save fuel.
To give an example consider two identical airliners A and B, with the same
number of pax (say 90% of capacity which would be a fairly common
utilisation rate today) and their luggage ie both have the same payload
weight. A allocates pax seats randomly while B sits them up front first so
that all empty seats are at the rear and so its CG is forward of A's. If
sitting everyone up front isn't enough to move the CG to its most forward
allowable limit then also placing the heaviest pallets and/or bags up front
could
also be done (they weight them anyhow so this information is already known)
to further move it forward to this limit (taking into account any zero fuel
weight CG limitations too of course). Then over the same travel distance
surely B would have a slightly lower total fuel burn since its tailplane
needs a smaller downforce (for the same payload weight) and hence produces
less drag.
Even if this were only done for cattle ah economy class it would surely
still have a noticeable effect but having flown a lot over the years on
various airlines I've never seen this done, why not??
baggage to minimise fuel burn? Since the tailplane has to provide a downward
force to balance the CG/CoP coupe, which to the wing is exactly the same as
carrying that amount of additional weight, by moving the CG forward could
save fuel.
To give an example consider two identical airliners A and B, with the same
number of pax (say 90% of capacity which would be a fairly common
utilisation rate today) and their luggage ie both have the same payload
weight. A allocates pax seats randomly while B sits them up front first so
that all empty seats are at the rear and so its CG is forward of A's. If
sitting everyone up front isn't enough to move the CG to its most forward
allowable limit then also placing the heaviest pallets and/or bags up front
could
also be done (they weight them anyhow so this information is already known)
to further move it forward to this limit (taking into account any zero fuel
weight CG limitations too of course). Then over the same travel distance
surely B would have a slightly lower total fuel burn since its tailplane
needs a smaller downforce (for the same payload weight) and hence produces
less drag.
Even if this were only done for cattle ah economy class it would surely
still have a noticeable effect but having flown a lot over the years on
various airlines I've never seen this done, why not??