AngelAirways
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A345 And 772LR Fuel Burn.

Tue Sep 19, 2006 10:00 pm

Can anyone here source reliable A340-500 and 777-200LR fuel burn figures?
 
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Stitch
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RE: A345 And 772LR Fuel Burn.

Tue Sep 19, 2006 10:19 pm

The closest I can find is from Widebodyphotog's "772LR/A345 Mission Comparison Analysis". I'm pretty sure he uses industry numbers for these calculations, not personal speculation, so they should be valid for comparison purposes.

For a mission entailing flying 65,730lbs of payload 8,670nm, the 772LR requires 46,403 gallons of fuel vs. 56,174 gallons for the A345 (non-HGW). So an A345 will burn roughly 20% more fuel in this mission and will arrive 20 mins after the 772LR.

[Edited 2006-09-19 15:20:33]
 
cobra27
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RE: A345 And 772LR Fuel Burn.

Tue Sep 19, 2006 10:27 pm

Quoting Stitch (Reply 1):
20% more fuel

So the A345 burns something like 747 classic but has more range?
 
Geo772
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RE: A345 And 772LR Fuel Burn.

Tue Sep 19, 2006 10:49 pm

Quoting Cobra27 (Reply 2):

So the A345 burns something like 747 classic but has more range?

No.

For the same range it will burn less. Remember that the longer the range an aircraft has the more fuel it has to cart around with it. Therefore the overall fuel burn will appear to be higher.

But still those numbers are heavily in favour of 777 operation with high fuel prices.
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WINGS
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RE: A345 And 772LR Fuel Burn.

Tue Sep 19, 2006 10:53 pm

Quoting Stitch (Reply 1):
For a mission entailing flying 65,730lbs of payload 8,670nm, the 772LR requires 46,403 gallons of fuel vs. 56,174 gallons for the A345 (non-HGW). So an A345 will burn roughly 20% more fuel in this mission and will arrive 20 mins after the 772LR.

Lets not forget that the B777LR can also transport more cargo and passengers vs the A345.

Regards,
Wings
Aviation Is A Passion.
 
WINGS
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RE: A345 And 772LR Fuel Burn.

Tue Sep 19, 2006 11:23 pm

Quoting Geo772 (Reply 3):
But still those numbers are heavily in favour of 777 operation with high fuel prices.

While the number will easily give the B777LR the victory, their are some factors in which the A345 has an advantage.

-It has no ETPOS restrictions.
-Quieter Cabin.
-Cockpit commodity with A32X/A330/A350/A380.

While some members easily dismiss these facts then surely will contribute to a final decision.

Regards,
Wings
Aviation Is A Passion.
 
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zeke
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:09 am

Quoting Stitch (Reply 1):
For a mission entailing flying 65,730lbs of payload 8,670nm, the 772LR requires 46,403 gallons of fuel vs. 56,174 gallons for the A345 (non-HGW). So an A345 will burn roughly 20% more fuel in this mission and will arrive 20 mins after the 772LR.



I dont know about the particular mission, I would disagree that its 20% across the board.

Quoting WINGS (Reply 4):
Lets not forget that the B777LR can also transport more cargo and passengers vs the A345.

Tell that to PIA who cannot get that performance from their 772LRs due to the departure aerodrome.

Be very careful coming up with blanket one fits all statements, some missions the 345 will be better than a 772LR, one of the reasons why SA chose the 346 over the 773ER.

The 772LR has the same list price as the 744, it is a very expensive aircraft to purchase for its size. (http://www.boeing.com/commercial/prices/). The 380 is about $280m, 345 $198m.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
sebring
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:12 am

Quoting Zeke (Reply 6):
The 772LR has the same list price as the 744, it is a very expensive aircraft to purchase for its size. (http://www.boeing.com/commercial/prices/). The 380 is about $280m, 345 $198m.

And these prices have no correlation with reality. AC's two 345s ended up cost $87 million each.

You can also rest assured that AC got a fantastic price on its 777s and a number of interesting cost caps that don't appear on the master contract.
 
WINGS
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:16 am

Quoting Zeke (Reply 6):
Tell that to PIA who cannot get that performance from their 772LRs due to the departure aerodrome.

Has this information actually been confirmed? We previously got a news report stating that PIA was rather unhappy with the B777LR performance although, many around here quickly dismissed it as bad journalism.

PS: On another matter, could you please get in contact with me.

Regards,
Wings
Aviation Is A Passion.
 
Thorben
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:24 am

Quoting Zeke (Reply 6):
I dont know about the particular mission, I would disagree that its 20% across the board.

I think those are made up missions. Given that the T7 has the longer range, at some point you could find a figure where it can carry 2 tons of payload and the A345 only one. That would seem the T7 to give twice the performance.

Anyway, Tim Clarke will have both in his fleet and he once said they have roughly the same over-all economics.

Quoting Zeke (Reply 6):
Tell that to PIA who cannot get that performance from their 772LRs due to the departure aerodrome.

They also said that due to the high weight the LR can not reach its best altitude until some fuel is burned, therefore it uses more fuel and has a shorter range than actually claimed by Boeing.

Quoting Sebring (Reply 7):
And these prices have no correlation with reality. AC's two 345s ended up cost $87 million each.

How do you know?
France 1789; Eastern Germany 1989; Tunisia 2011; Egypt 2011
 
brendows
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:32 am

Quoting Thorben (Reply 9):
I think those are made up missions. Given that the T7 has the longer range, at some point you could find a figure where it can carry 2 tons of payload and the A345 only one.

Made up? Take a look at this chart made by Widebodyphotog:
http://theaviationspecialist.com/777-200lr_a340-500s_fmission.gif
And then check out his profile, and the hundreds of posts he has made concerning the performance of jets. In the end, every mission is made up, since you have to check out how a jet will perform on such a mission, based on data from the manufacturer. Widebodyphotog isn't spinning the numbers, they are real. Don't you believe me, or his numbers? Then, check out the payload-range charts for the A345 and 772LR and do the math. You can find the charts here:
A340-500/-600 ACAP
777NG ACAP
Hope you're able to understand the numbers.

Quoting Thorben (Reply 9):
Anyway, Tim Clarke will have both in his fleet and he once said they have roughly the same over-all economics.

When it comes to fuel burn, no, not anymore with the fuel prices we have today.

Quoting Thorben (Reply 9):
How do you know?

If you had been reading this forum for long enough, you wouldn't even ask him that question.
 
irobertson
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:32 am

Anyone know if the A345s and 346s currently in service will get the HGW upgrade or if this will only be on new build aircraft? (might be a stupid question, forgive me)
 
Thorben
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:35 am

Quoting Irobertson (Reply 11):
Anyone know if the A345s and 346s currently in service will get the HGW upgrade or if this will only be on new build aircraft? (might be a stupid question, forgive me)

I think the HGW is so different that it would be very costly to fit that into the older models. I also heard that the ones built from now on will all be HGW versions.
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WINGS
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:40 am

Quoting Thorben (Reply 12):

I think the HGW is so different that it would be very costly to fit that into the older models. I also heard that the ones built from now on will all be HGW versions.

That's correct Thorben, all future A345/A346 will soon only be delivered with the HGW option.

One of the main difference between the A346/A345 and the HGW version is that the latter will use solder welding to join the fuselage panels.

I would expect that the current non HGW operators would be able to adapt engine upgrade.

Regards,
Wings
Aviation Is A Passion.
 
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Stitch
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:50 am

Quoting WINGS (Reply 4):
Lets not forget that the B777LR can also transport more cargo and passengers vs the A345.

True, but these were identical missions in terms of payload and range to provide a direct comparison between the two, which is what the OP was asking for.

And actually, the A345 carries about 2000lbs more payload at MTOW, however the 772LR flies 1030nm farther.

Quoting Zeke (Reply 6):
I dont know about the particular mission, I would disagree that its 20% across the board.

That is probably true, which is why I bolded "this mission" because I did not want to give the impression that an A345 always burns 20% more fuel regardless of mission.

The A345HGW, for example, hauling 65,730lbs 9,000nm burns 58,039 gallons. The 772LR hauling 63,210lbs 9,700nm burns 53,400 gallons, so it's more like 8% when both planes are at max load and range, though the 772LR does have a nominal 700nm range advantage.

Quoting Thorben (Reply 9):
I think those are made up missions.

As I indicated, it is a hypothetical mission with identical payloads and range. So for that specific mission, it's 20% but for another mission, it's only 8%.
 
Thorben
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:50 am

Quoting WINGS (Reply 13):
I would expect that the current non HGW operators would be able to adapt engine upgrade.

How usefull would that be? The HGW has stronger engines that are not really needed for the non-HGW. Or do you mean adapting engine improvements to the weaker engines when they get new engines? How often are engines changed?
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WINGS
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:55 am

Quoting Thorben (Reply 15):
How usefull would that be? The HGW has stronger engines that are not really needed for the non-HGW. Or do you mean adapting engine improvements to the weaker engines when they get new engines? How often are engines changed?

I meant upgrade kits for existing A345/6 operators. I would imagine that the HGW version should also incorporate better fuel saving vs the previous version.

Regards,
Wings
Aviation Is A Passion.
 
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zeke
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:11 am

Quoting WINGS (Reply 8):
Has this information actually been confirmed? We previously got a news report stating that PIA was rather unhappy with the B777LR performance although, many around here quickly dismissed it as bad journalism.

All twins suffer more hot and high one engine out than quads do, this is not something to new.

Quoting Thorben (Reply 9):
Anyway, Tim Clarke will have both in his fleet and he once said they have roughly the same over-all economics.

Correct.

Quoting Stitch (Reply 14):
That is probably true, which is why I bolded "this mission" because I did not want to give the impression that an A345 always burns 20% more fuel regardless of mission.

The A345HGW, for example, hauling 65,730lbs 9,000nm burns 58,039 gallons. The 772LR hauling 63,210lbs 9,700nm burns 53,400 gallons, so it's more like 8% when both planes are at max load and range, though the 772LR does have a nominal 700nm range advantage.

Widebodyphotog does fantastic work, he is on my RR list.

However unless I could compare the flight plans of the two missions I could not conclude its a fair comparison. For example, one I previously looked out had a B product at its optimum altitude in a block climb and an A product cruising at non optimum constant altitude. If I recall correctly it was done this way for airspace constraints on the mission profile which were of similar lengths, however not over the same route.

He does great work, the trends in my view are a true and fair indication of the aircraft capabilities, however one should exercise caution taking them as gospel for all situations or for making percentage difference comparisons unless one knows all the background of the mission analysed.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
BoomBoom
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:17 am

Quoting Thorben (Reply 9):
Anyway, Tim Clarke will have both in his fleet and he once said they have roughly the same over-all economics.

Nonsense.

All one has to do is look at the lopsided sales totals for last year--the 777 outsold the A340 by something like 120 to 15. The fact that this happened in a year when fuel prices set new records, tells you a lot.

That's why Airbus is replacing the A340 with a 9-across in Y twin.
Our eyes are open, our eyes are open--wide, wide, wide...
 
khobar
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:50 am

Quoting WINGS (Reply 8):
Has this information actually been confirmed? We previously got a news report stating that PIA was rather unhappy with the B777LR performance although, many around here quickly dismissed it as bad journalism.

I recall PIA's problems with their T7's stemmed from minor details in the fit and finish of the aircraft. Some people tried to make a conspiracy issue out of the fact that Boeing was going to fix those items for free - under warranty.
 
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Stitch
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:58 am

Quoting Zeke (Reply 17):
He does great work, the trends in my view are a true and fair indication of the aircraft capabilities, however one should exercise caution taking them as gospel for all situations or for making percentage difference comparisons unless one knows all the background of the mission analysed.

 checkmark 
 
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Starlionblue
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 2:22 am

Quoting BoomBoom (Reply 18):
All one has to do is look at the lopsided sales totals for last year--the 777 outsold the A340 by something like 120 to 15. The fact that this happened in a year when fuel prices set new records, tells you a lot.

Not really a conclusive argument. There are dozens of factors involved, fuel burn being one of them.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
BoomBoom
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 2:48 am

Quoting Starlionblue (Reply 21):
Not really a conclusive argument. There are dozens of factors involved, fuel burn being one of them.

I said it "tells you a lot", I didn't say it tells you everything.
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Glareskin
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 3:06 am

Quoting BoomBoom (Reply 18):
All one has to do is look at the lopsided sales totals for last year--the 777 outsold the A340 by something like 120 to 15.

It's always nice to use the total T7 sales as comparison. As for the LR I feel it's the best aircraft nobody wants.....
There's still a long way to go before all the alliances deserve a star...
 
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Stitch
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 3:14 am

Quoting Glareskin (Reply 23):
As for the LR I feel it's the best aircraft nobody wants...

Some would argue the same about the A388, however I prefer to be thankful that at least 134 of them are wanted, along with 40 772LRs and 26 A345s.

As an aviation enthusiast, I am impressed with the the A388 on a technical accomplishment level.

As an aviation enthusiast, I am impressed with the the 772LR on both a technical accomplishment level and an aesthetic level (as I believe the 777 is the prettiest commercial airliner family in current service).

As an aviation enthusiast, I am impressed with the the A345 on an aesthetic level as I believe it is a very well-balanced and graceful airplane.

And as an aviation enthusiast, I am pleased that I have been able to see all three models in person.
 
PolymerPlane
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 3:52 am

Quoting Starlionblue (Reply 21):
Not really a conclusive argument. There are dozens of factors involved, fuel burn being one of them.

With LR's price is rumoured to be much higher than 345/6, it is pretty good argument in my opinion. Why would anybody buy a more expensive aircraft with only marginal economic advantage. It all boils down to the overall cost of ownership. If airlines buy more expensive planes, I bet they are counting on the operational cost savings to regain their capital costs. Maintenance is one thing. But my guess is that fuel burn plays a big role in it.

Cheers,
PP
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manny
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 4:32 am

Quoting PolymerPlane (Reply 25):

With LR's price is rumoured to be much higher than 345/6, it is pretty good argument in my opinion. Why would anybody buy a more expensive aircraft with only marginal economic advantage. It all boils down to the overall cost of ownership. If airlines buy more expensive planes, I bet they are counting on the operational cost savings to regain their capital costs. Maintenance is one thing. But my guess is that fuel burn plays a big role in it.

What would the fuel burn savings amount to annually ?
 
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Starlionblue
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 5:16 am

Quoting BoomBoom (Reply 22):
Quoting Starlionblue (Reply 21):
Not really a conclusive argument. There are dozens of factors involved, fuel burn being one of them.

I said it "tells you a lot", I didn't say it tells you everything.

Fair enough. But I would not say it tells me a lot. I would say it tells me something. Just an opinion.  Wink

Quoting Manny (Reply 26):

What would the fuel burn savings amount to annually ?

That's an impossible question to answer without a specific route and load average in mind. There are huge variations.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
prebennorholm
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 5:28 am

On the mission mentioned by Stitch in reply #1 savings would roughly be $200 per seat. If we assume 300 such sectors per year it would be some 15-20 million per plane per year.

On some routes that difference will in practice be somewhat lower because of ETOPS restrictions. If for instance the 345 can fly a 10% shorter track, then it will burn a lot more than 10% less fuel compared to the 345 flying the ETOPS route, simply because it costs a lot of fuel to carry that extra fuel. In that case the 345 and T7LR fuel burn would be near equal.

Seldom are optimal ETOPS routes that much longer than shortest possible route. But not too seldom do ETOPS planes have to fly farther than optimal ETOPS routes since an important ETOPS alternate happens to be weathered out.

On the other hand both ETOPS and non-ETOPS planes will often divert around adverse weather en route. The non-ETOPS planes probably a little more than ETOPS planes because they climb more slowly and cruise at relatively low altitude until the fuel load is reduced.

But it takes very little ETOPS restrictions to make the 345 the faster plane.

There are a lot of variables. If only the rulers makers changed ETOPS-xxx to ETOPS-999, then it would be a lot easier to compare.
Always keep your number of landings equal to your number of take-offs
 
manny
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 5:40 am

Quoting Prebennorholm (Reply 28):
On the mission mentioned by Stitch in reply #1 savings would roughly be $200 per seat. If we assume 300 such sectors per year it would be some 15-20 million per plane per year.

On some routes that difference will in practice be somewhat lower because of ETOPS restrictions. If for instance the 345 can fly a 10% shorter track, then it will burn a lot more than 10% less fuel compared to the 345 flying the ETOPS route, simply because it costs a lot of fuel to carry that extra fuel. In that case the 345 and T7LR fuel burn would be near equal.

Seldom are optimal ETOPS routes that much longer than shortest possible route. But not too seldom do ETOPS planes have to fly farther than optimal ETOPS routes since an important ETOPS alternate happens to be weathered out.

On the other hand both ETOPS and non-ETOPS planes will often divert around adverse weather en route. The non-ETOPS planes probably a little more than ETOPS planes because they climb more slowly and cruise at relatively low altitude until the fuel load is reduced.

But it takes very little ETOPS restrictions to make the 345 the faster plane.

There are a lot of variables. If only the rulers makers changed ETOPS-xxx to ETOPS-999, then it would be a lot easier to compare.ET

Thanks for the answer. Thats some great info.
 
Rheinbote
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 6:22 am

Quoting WINGS (Reply 13):
One of the main difference between the A346/A345 and the HGW version is that the latter will use solder welding to join the fuselage panels.

It will use laser beam welding for some fuselage panels (lower lobe only)
 
Aviator27
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 6:34 am

Quoting Stitch (Reply 1):
For a mission entailing flying 65,730lbs of payload 8,670nm, the 772LR requires 46,403 gallons of fuel vs. 56,174 gallons for the A345 (non-HGW). So an A345 will burn roughly 20% more fuel in this mission and will arrive 20 mins after the 772LR.

Your analysis and reasoning is flawed. You cannot use range charts to compare fuel burns between two airplanes. It just doesn't work like that. For one, neither airplane can carry max payload and max fuel simultaneously. For what its worth, fuel burn between the two airplanes are almost identical. The Boeing benefits from being a twin with the associated lower maintenance cost.
 
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Stitch
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 7:02 am

Quoting Aviator27 (Reply 31):
Your analysis and reasoning is flawed.

Take it up with Widebodyphotog then, since I'm just repeating his dataset and conclusions.  

Quoting Aviator27 (Reply 31):
You cannot use range charts to compare fuel burns between two airplanes. It just doesn't work like that.

I'm not sure Widebodyphotog did that when he calculated his "Mission Fuel" numbers. My question is if you're taking the exact same payload the exact same distance on the exact same track, why can't you compare the fuel loads needed to do just that?

Quote:
For one, neither airplane can carry max payload and max fuel simultaneously.

His dataset does not use maximum fuel for either plane (based on what Boeing's and Airbus' sites note is the max fuel volume). I do not know how much his ~66,000lb mission payload is to the maximum payload the plane can carry 8,670nm. However, both planes were below their stated MTOWs with their respetive fuel loads and payloads.

Quoting Aviator27 (Reply 31):
For what its worth, fuel burn between the two airplanes are almost identical. The Boeing benefits from being a twin with the associated lower maintenance cost.


If it is indeed just maintenance costs, Trent 553's must have maintenance costs is in the scores of millions of dollars since the 772LR costs about $30 million more in 2001 dollars (last price I could find).

[Edited 2006-09-20 00:24:41]
 
phollingsworth
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 7:06 am

Quoting Aviator27 (Reply 31):
Your analysis and reasoning is flawed. You cannot use range charts to compare fuel burns between two airplanes. It just doesn't work like that. For one, neither airplane can carry max payload and max fuel simultaneously.

You are correct in that you cannot use range circles or max range numbers, but you can use payload range charts. Of course that only works if you have good ones. The numbers I have show a fuelburn advantage for the 777 (now the charts could be wrong). If you start at max ZFW (or max payload) and add fuel until you reach MTOW/MGTW you will have the fuel weight and the range for the corresponding mission. Obviously this tactic only works if the MZFW or MPL are the same but the lines can be drawn at different payloads. You can also go to other range and payload points and calculate fuel required (depending on the detail of the charts). Anyhow, for similar payloads the 340 and the 777 seem to burn similar amounts of fuel at ~7200 nm; however, by 9100 nm not only does the 777 burn less fuel but it also carries more PL. Or for similar payloads the 777 burns even less fuel.

Quoting Aviator27 (Reply 31):
For what its worth, fuel burn between the two airplanes are almost identical.

Do you have a source for this?
 
flydreamliner
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 7:47 am

Quoting BoomBoom (Reply 18):
That's why Airbus is replacing the A340 with a 9-across in Y twin.

It's a strong vindication for the notion of the big twin. Especially in times of high fuel prices, Boeing's foresight and impressive engineering on 777 are especially apparent.

That said, if fuel prices kept at where they were in say 1996, the A340 may very well be considder every bit as good - if not a better aircraft. The strongest thing 777 has going for it is efficiency.

Quoting BoomBoom (Reply 18):
All one has to do is look at the lopsided sales totals for last year--the 777 outsold the A340 by something like 120 to 15. The fact that this happened in a year when fuel prices set new records, tells you a lot.

It does, and when you look at airlines like AC - retiring in some cases almost brand new A340's to be replaced with 772LR and 773ER, it shows that in this market - with these fuel prices, the 777's efficiency, versatility, and capacity (advantages that in essence originate from its wider fuselage and twin engine design) make it very attractive.
"Let the world change you, and you can change the world"
 
Aviator27
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 8:51 am

I'm sorry but your analysis still doesn't pass the logic test. How can two airplanes burn the same amount of fuel for 7200 nm and then one of them burn 20% more in the remaining 1900 nm (9100 nm -7200 nm = 1900 nm). Like I said, your analysis is just flawed. You still cannot use any range charts (whether max range or payload range) to calculate trip fuel. I don't have charts I can link online to provide any data. Your information is wrong and you need to delete them. Period. Its hard to find a system with both B777-200LR and A340-500 figures loaded into the flight planning computers. I will work on it and get back to you guys. Check what Emirates Clark said about the economics of both airplanes (he said they were almost identical).
 
BoomBoom
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 9:07 am

Quoting Aviator27 (Reply 36):
Check what Emirates Clark said about the economics of both airplanes (he said they were almost identical).

Unfortunately, no one has provided a source to check.
Our eyes are open, our eyes are open--wide, wide, wide...
 
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Stitch
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 9:38 am

Quoting Aviator27 (Reply 36):
I'm sorry but your analysis still doesn't pass the logic test. How can two airplanes burn the same amount of fuel for 7200 nm and then one of them burn 20% more in the remaining 1900 nm (9100 nm -7200 nm = 1900 nm).

Yeah, I muffed that quote so have asked the mods to delete Reply #33.

Quoting Aviator27 (Reply 36):
Like I said, your analysis is just flawed. You still cannot use any range charts (whether max range or payload range) to calculate trip fuel. I don't have charts I can link online to provide any data.

Many of Widebodyphotog's charts include the "Fuel Consumption per Hour" rate. Now I imagine that rate is the cruise consumption rate, so take-off, climb, and descent consumption rates may not be included, but if nothing else it at least sets a trend since the plane spends most of it's time at cruise.

If you'd like to see the charts I drew my statements from, they are available at http://theaviationspecialist.com/777-200lr_a340-500s_dmission.gif. I used the two center columns.

Quoting Aviator27 (Reply 36):
Its hard to find a system with both B777-200LR and A340-500 figures loaded into the flight planning computers. I will work on it and get back to you guys.

Thank you. It's always nice to get a "second opinion" and it would be helpful to be able to take both planes, load them with the same payload, fly them the same distances, and account for their differences in take-off, climb, cruise, and descent fuel consumption rates to make the final data as accurate as possible.

Quoting Aviator27 (Reply 36):
Check what Emirates Clark said about the economics of both airplanes (he said they were almost identical).

Perhaps Mr. Clark was just being polite towards Airbus? Or was not trying to make Boeing think that he would be willing to pay more for the 772LR because it would save him money in fuel burn?
 
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Stitch
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 10:33 am

Quoting Stitch (Reply 38):
Yeah, I muffed that quote so have asked the mods to delete Reply #33.

I meat to say Reply #34 - my reply to Phollingsworth - and not Phollingsworth's reply itself.
 
PolymerPlane
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 11:19 am

Quoting Aviator27 (Reply 31):
For what its worth, fuel burn between the two airplanes are almost identical. The Boeing benefits from being a twin with the associated lower maintenance cost.

Uh... NO.... even Leahy admitted that the fuel burn is higher on A345/6 compared to 777LR. He even offered to pay for the difference in the fuel consumption. Sorry.. wrong.. check your source and post.

Quoting Aviator27 (Reply 36):
Check what Emirates Clark said about the economics of both airplanes (he said they were almost identical).

Uh.. economics includes cost of capital, with 777LR being higher.

Plus you just said that 777 has a lower maintenance cost, yet you just said with "almost identical" economics. You can't have it both way sir.

Clark can say whatever he wants, but the fact that EK purchased a boat load of 777LR even with A340s are already in their fleet, and then refused to take delivery of the A340HGW, says a lot about 777LR vs. A345/6 economics

Quoting Aviator27 (Reply 31):
For one, neither airplane can carry max payload and max fuel simultaneously

Nothing in his post even remotely suggest maximum payload and max fuel simultaneously.

Quoting Aviator27 (Reply 36):
Like I said, your analysis is just flawed. You still cannot use any range charts (whether max range or payload range) to calculate trip fuel

why not? the payload-range chart incorporates the limitation of the aircraft at a given payload with the rest of weight is used as fuel, or that the fuel tanks is full, at least at the slanted part of the curve. That is why the shape of the payload-range chart looks as such. You can calculate how much fuel you fit into an aircraft as long as you are at the slanted boundary of the payload-range chart.

BTW, widebodyphotog's chart does not even use the payload-range chart to calculate. He is working in the aviation analysis, with access to flight planning computer.

Cheers,
PP

[Edited 2006-09-20 04:21:31]
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zeke
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:07 pm

Quoting BoomBoom (Reply 37):
Unfortunately, no one has provided a source to check.

Its is easy to see that an aircraft that has been in service for a number of years pays itself off before a newer one.

I cannot see how a 772LR at EK introduced today could have a lower cost of ownership to EK than a A345 which has been in service for some time.

The 772LR is a very expensive aircraft to purchase, and has only been available on the market for a relatively short period of time, the fuel burn delta does not change the total cost of ownership that far in this case.

I think you may have made the mistake of thinking that fuel burn is the only factor in aircraft economics, its just one of the direct operating costs.

Even if you were to put an A345 and 772LR online today, it would be some time before the fuel burn difference made up the purchase price difference.
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Aviator27
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:30 pm

Quoting Stitch (Reply 1):
For a mission entailing flying 65,730lbs of payload 8,670nm, the 772LR requires 46,403 gallons of fuel vs. 56,174 gallons for the A345 (non-HGW). So an A345 will burn roughly 20% more fuel in this mission and will arrive 20 mins after the 772LR.

I checked out widebodyphotogs gif image so I can use his numbers.

The first glaring difference that shows is that the B777-200LR takes off at 315,082 kgs and the A340-500 takes off at 368,000 kgs. That is a 52,918 kgs difference in weights. The difference in OEW + fuel burn doesn't account for this glaring mathematical error. I am not sure where this person gets their data but, it is not passing the simple logic test.

Another invalid comparison you find are the payload numbers. Both airplanes have identical payload. But look at how they arrive at them. The A340 is carrying more passengers and bags (313 versus 301 pax / 7099 kgs versus 6827 kgs bags). The B777 makes up the difference by revenue payload. So hence people say the B777 can carry the same pax/bags and still carry 2000 kgs more of payload. That's incorrect.

Also listed on the page is specific fuel consumption as lbs of fuel per pound of thrust. This compares engine efficiency and not airplane cruise fuel flow. It is suppose give you the mass of fuel needed to provide a given power for a given period (Fuel/Thrust/Time).

Another error you can spot are the fuel burn-off numbers for 9700 nm versus 8670 nm. The A340-500 burns only an additional 710 kgs (51849 - 51139) to fly that extra 1030 nm. The B777-200LR on the other hand burns an additional 6634 kgs (48,813 - 42,179) to fly that same extra 1030 nm. Bad error.

Look at the data, and just use common sense. You can spot the errors like a Redcoat in the Catskills.

Last but not least, you cannot use the charts to work backwards to get fuel burn. The charts aren't for flight planning purposes but for general informational purposes. Those documents are airport planning guides. You need cruise charts or access to flight planning computer with respective airplane parameters loaded in them.

With all these errors, you cannot use this information for any serious analysis or comparison.

http://theaviationspecialist.com/777-200lr_a340-500s_fmission.gif
 
futurecaptain
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:33 pm

Quoting Aviator27 (Reply 36):
Clark said about the economics of both airplanes (he said they were almost identical).



Quoting Aviator27 (Reply 31):
For what its worth, fuel burn between the two airplanes are almost identical.

777-200LR burns around 1.79 gal / mi
A340-500 burns around 2.23 gal / mi

Not a big difference, but over the course of a 10000 mi trip it adds up.
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worldtraveler
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 12:43 pm

you bet it's a significant difference - about 20% each and every minute.

Quoting Manny (Reply 29):
ET

Thanks for the answer. Thats some great info.

not really. he just talked in circles and still demonstrated nothing that says the A345 or any quad has an advantage. In practicality, there are very few restrictions on where the 777 can fly... and the FAA is moving toward applying consistent restrictions on all long haul aircraft, regardless of the number of engines.

Oh, I noticed that SQ has stopped their JFK-SIN flights. Could it be that the ECONOMICS of the 345 just don't work for the route, esp. when the plane can only carry 1/2 of the people it needs to in order to make money?
 
PolymerPlane
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:19 pm

Quoting Aviator27 (Reply 42):
I checked out widebodyphotogs gif image so I can use his numbers.

The first glaring difference that shows is that the B777-200LR takes off at 315,082 kgs and the A340-500 takes off at 368,000 kgs. That is a 52,918 kgs difference in weights. The difference in OEW + fuel burn doesn't account for this glaring mathematical error. I am not sure where this person gets their data but, it is not passing the simple logic test.

When you want to criticize one's work, please really check your facts and numbers. widebodyphotog's calculation is perfectly accurate. OEW difference: 772LR 145,151 kg vs. A345 168,468 kg, a difference of 23,317 kg. Mission fuel: 772LR 141,023 kg vs A345 170,717 kg, a difference of 29,694 kg. That's a total of 53,011kg. pretty darn close to 52,918 kg. The difference is probably from lb to kg conversion.

Quoting Aviator27 (Reply 42):
Another invalid comparison you find are the payload numbers. Both airplanes have identical payload. But look at how they arrive at them. The A340 is carrying more passengers and bags (313 versus 301 pax / 7099 kgs versus 6827 kgs bags). The B777 makes up the difference by revenue payload. So hence people say the B777 can carry the same pax/bags and still carry 2000 kgs more of payload. That's incorrect.

hmm... it's valid since the plane for that comparison does not take off at MTOW. The comparison is made at similar payload just for fair comparison. 772LR has a lot more extra capability than what is represented in the chart. For example, the mission take off weight for 772LR is 694,630 lbs while the MTOW is 766,800 lbs, while A345's mission weight is at MTOW.

Quoting Aviator27 (Reply 42):
Another error you can spot are the fuel burn-off numbers for 9700 nm versus 8670 nm. The A340-500 burns only an additional 710 kgs (51849 - 51139) to fly that extra 1030 nm. The B777-200LR on the other hand burns an additional 6634 kgs (48,813 - 42,179) to fly that same extra 1030 nm. Bad error.

Not an error... the take off weight is different, thus the weight you need to haul is also different. More weight=more fuel burn. Look at the payload difference 2,800 kg vs 30,000 kg. You are comparing washington and fuji apples in terms of the fuel burn.

Quoting Aviator27 (Reply 42):
Also listed on the page is specific fuel consumption as lbs of fuel per pound of thrust. This compares engine efficiency and not airplane cruise fuel flow. It is suppose give you the mass of fuel needed to provide a given power for a given period (Fuel/Thrust/Time).

You have no argument here. SFC is a valid quantity in aviation for engine fuel burn. He represents the figure just for comparison at cruise. The efficiency figure is calculated not from SFC but the overall fuel burn.

Quoting Aviator27 (Reply 42):
Look at the data, and just use common sense. You can spot the errors like a Redcoat in the Catskills.

Uh.. I don't think so.. I have not seen your common sense that points anything wrong with widebodyphotog's chart... If you care not to be so ignorant and actually with care calculating it yourself, you'll see that his chart is actually accurate in numberwise.

I can't comment on the methodology, since I do not know much about aircraft mission planning.

Quoting Aviator27 (Reply 42):
Last but not least, you cannot use the charts to work backwards to get fuel burn. The charts aren't for flight planning purposes but for general informational purposes. Those documents are airport planning guides. You need cruise charts or access to flight planning computer with respective airplane parameters loaded in them.

You don't even know what he uses to come up with this numbers. If you care enough to read other people's comment, widebodyphotog DOES NOT solely use the payload-chart to come up with this numbers. He actually uses computer program generally use in aviation industry to come up with this numbers, with actual flight parameters.

I think you should sit down and be more careful before criticizing one's work. Do you think you're the only one in this forum that has actually analyze his work?

Cheers,
PP
One day there will be 100% polymer plane
 
Lemurs
Posts: 1320
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:23 pm

Quoting WorldTraveler (Reply 44):
Oh, I noticed that SQ has stopped their JFK-SIN flights. Could it be that the ECONOMICS of the 345 just don't work for the route, esp. when the plane can only carry 1/2 of the people it needs to in order to make money?

Yes, but it's also easy to believe that they really botched the marketing of that flight so badly that they couldn't get the yields that it is truly capable of...and when you're operating on what is probably a razor thin margin on such a long flight with a low seat count, it only needs to be a small foul up to really screw you.

I have nothing to say about the economics of either airplane, I just don't think SQ at JFK proves anything about one frame versus another.
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zeke
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:27 pm

Quoting WorldTraveler (Reply 44):
not really. he just talked in circles and still demonstrated nothing that says the A345 or any quad has an advantage. In practicality, there are very few restrictions on where the 777 can fly... and the FAA is moving toward applying consistent restrictions on all long haul aircraft, regardless of the number of engines.

Total B/S, the 748i will have a lower CASM than any twin Boeing produce. Its will also have operational advantages over any twin that Boeing produce over ULH legs.

Quoting WorldTraveler (Reply 44):
Oh, I noticed that SQ has stopped their JFK-SIN flights. Could it be that the ECONOMICS of the 345 just don't work for the route, esp. when the plane can only carry 1/2 of the people it needs to in order to make money?

You mean the EWR flights ? Just jumped onto the web site had a look at June July next year ... guess what

Singapore Airlines SQ 22, (Nonstop)
Singapore(SIN) - New York (EWR)
12:05 - 17:30
Airbus Industrie A340-500

Total Travel Time 18:25

Singapore Airlines SQ 21, (Nonstop)
New York(EWR) - Singapore (SIN)
23:00 - 05:40
Airbus Industrie A340-500

Total Travel Time 18:40

Sounds like even more B/S.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
PolymerPlane
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 1:29 pm

Quoting WorldTraveler (Reply 44):
Oh, I noticed that SQ has stopped their JFK-SIN flights. Could it be that the ECONOMICS of the 345 just don't work for the route, esp. when the plane can only carry 1/2 of the people it needs to in order to make money?



Quoting Lemurs (Reply 46):
I have nothing to say about the economics of either airplane, I just don't think SQ at JFK proves anything about one frame versus another.

SQ flies A345 directly to EWR, never to JFK. JFK flight is a 744 with a stopover in FRA. I just checked the online booking, SQ 21 and 22 SIN-EWR are still on the market.

Cheers,
PP
One day there will be 100% polymer plane
 
BoomBoom
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 2:15 pm

Quoting Zeke (Reply 41):
Quoting BoomBoom (Reply 37):
Unfortunately, no one has provided a source to check.

Its is easy to see that an aircraft that has been in service for a number of years pays itself off before a newer one.

That's nice, but that's not what I asked for.

Where did Mr. Clark say the A340 and 777 have roughly the same over-all economics? Please provide a source.
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baroque
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RE: A345 And 772LR Fuel Burn.

Wed Sep 20, 2006 2:36 pm

Quoting WINGS (Reply 13):
One of the main difference between the A346/A345 and the HGW version is that the latter will use solder welding to join the fuselage panels.

I would expect that the current non HGW operators would be able to adapt engine upgrade.



Quoting Rheinbote (Reply 30):
It will use laser beam welding for some fuselage panels (lower lobe only)

Does this mean that some of the improvements that would have been on the A340E or whatever it was going to be are going to be filtered into production? How much can RR improve the Trents?

The arguments about fuel burn are totally fascinating even if a bit eye-glazing. The more that is written on the topic, the more complex it seems to become.

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