art
Posts: 2680
Joined: Tue Feb 08, 2005 11:46 am

ULR Flights Are An Irresponsible Waste Of Fuel?

Sun Aug 12, 2007 10:52 am

It occurs to me that if an aircraft flies direct from Europe to Australia, it has to carry about twice as much fuel as it would if it stopped to refuel at half distance. For the first half of the direct flight, the aircraft will be carrying tens of tons of fuel more than if it was fuelled to stop halfway.

Even allowing for extra fuel used to descend and climb due to a technical stop, I wonder how much extra fuel is used flying direct (for the payload carried) compared with that used if a technical stop is made. My guess is that there is a dramatic increase. in fuel consumption per payload ton That seems a pretty irresponsible way for long distance aviation to operate. Should airlines (and manufacturers) therefore abandon the idea of ULR flights? Should governments put punitive taxes on such flights to discourage them?
 
ILOVEA340
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Joined: Sat Oct 30, 1999 9:49 am

RE: ULR Flights Are An Irresponsible Waste Of Fuel?

Sun Aug 12, 2007 10:58 am

It's actually far less efficient to do a refueling stop. I know it was looked into for a couple of potential routes with my company and the fuel burn of takeoff and climb far outweighs any gains from having a lighter aircraft.
 
OB1504
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Joined: Tue Jul 27, 2004 5:10 am

RE: ULR Flights Are An Irresponsible Waste Of Fuel?

Sun Aug 12, 2007 11:45 am

I just hope politicians don't do a Google search on ULR flights, read only the thread-starter, and decide to tax the hell out of them.  vomit 
 
worldtraveler
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Joined: Tue Aug 05, 2003 6:18 am

RE: ULR Flights Are An Irresponsible Waste Of Fuel?

Sun Aug 12, 2007 11:51 am

if the thesis was true, airlines would be constantly cutting routes "in half" in search of the supposedly lower fuel burn. obviously, the thesis is not correct.
 
WingedMigrator
Posts: 1769
Joined: Wed Oct 26, 2005 9:45 am

RE: ULR Flights Are An Irresponsible Waste Of Fuel

Sun Aug 12, 2007 12:09 pm

Quoting Art (Thread starter):
I wonder how much extra fuel is used flying direct

Roughly 15% more, using the same (heavy) ULR aircraft, or 20% more if you account for the fact that the one-stop flight can be flown at the same payload with a lighter non-ULR aircraft.

Quoting ILOVEA340 (Reply 1):
It's actually far less efficient to do a refueling stop. I know it was looked into for a couple of potential routes with my company and the fuel burn of takeoff and climb far outweighs any gains from having a lighter aircraft.

Since it is unlikely that 15% of the fuel load is used for takeoff and climb, I highly doubt this assertion.

Quoting WorldTraveler (Reply 3):
if the thesis was true, airlines would be constantly cutting routes "in half" in search of the supposedly lower fuel burn. obviously, the thesis is not correct.

Dubai is (and increasingly will be) a great example.
 
art
Posts: 2680
Joined: Tue Feb 08, 2005 11:46 am

RE: ULR Flights Are An Irresponsible Waste Of Fuel?

Sun Aug 12, 2007 6:28 pm

Quoting WorldTraveler (Reply 3):
if the thesis was true, airlines would be constantly cutting routes "in half" in search of the supposedly lower fuel burn. obviously, the thesis is not correct.

There are other factors at play - an extra compression/decompression cycle, landing costs etc