Fuel consumption data

[DanDan]

Changed my LH fleet now, from A310 to A350. According to aircraft datasheets, the A350 use slightly more than the A310.
What happened? My companies total fuel consumption went from 34kt per week to about 29kt...

Sami, would be great if we could get more data than just a kg/h on "an average-length flight for this aircraft size class." (Which doesn't make sense either since they are the same aircraft size class.)

[DanDan]

Picture

[groundbum2]

un TMT it says a350-800 4850kg/hr and a310-300 5470kg/hr, so more. Also flight speed is 487 v 453 so the A350 will spend less time in the air so less fuel.

If it's not too late since the switch you could look at the extended stats for a few routes (in view routes, bottom of page) and see the fuel used when the A310 used the route versus the A350 now.

But the chart looks correct to me. In TMT though I'm scratching my head wondering with EGLL-WSSS routes on A346 use less fuel than a A330NEO, I've not tracked that down yet.

[DanDan]

un TMT it says a350-800 4850kg/hr and a310-300 5470kg/hr, so more. Also flight speed is 487 v 453 so the A350 will spend less time in the air so less fuel.

If it's not too late since the switch you could look at the extended stats for a few routes (in view routes, bottom of page) and see the fuel used when the A310 used the route versus the A350 now.

But the chart looks correct to me. In TMT though I'm scratching my head wondering with EGLL-WSSS routes on A346 use less fuel than a A330NEO, I've not tracked that down yet.

well, i use 15x -900 and 7x -1000. so they use more fuel in average. sure, speed makes a bit of a difference, maybe 8%.

but the 22 planes are not all my fleet. i have about 70 in total. and the total companies fuel consumption dropped by 15%!

[groundbum2]

C and D checks? seat re-config? As you've said the company fuel chart is too imprecise, you need to look at key flights to see what they show you. Otherwise we're going in circles..

Also if the A310s were old planes they'd have had a fuel penalty of 3% or more applied to them..

Simon

[DanDan]

well, Sami will know quite well how the fuel consumption figure respectively fuel consumption is being calculated, and hopefully realize if there is merit to this report or not.

i do not understand why you claim i said the company fuel consumption chart ist too imprecise. i did not say that. i just said that there is other factors that certainly can influence it as well. but the consumption went from a rather steady consumption around the 34200t line to a steady consumption around the 29600t line. by changing 22 out of about 70 planes in my company to an airplane that is supposed to have roughly equal fuel consumption. C and D checks are not of relevance (believe me, one knows when there are C&D checks of 24year old planes).
and the 5% old plane penalty is not going to be enough to account for this.

interestingly: i now added 6 more planes to my A350 fleet in service. consumption is now at about the same level as it was before. meaning 28 A350 consume about as much as the 22 A310. in my opinion, the fuel consumption figures of a planetype are inprecise.

[groundbum2]

but you're refusing to look at the route data for routes flown by the A350? You can't just say "it's broken, fix it" without a small amount of detective work to narrow it down.

[DanDan]

but you're refusing to look at the route data for routes flown by the A350? You can't just say "it's broken, fix it" without a small amount of detective work to narrow it down.

i am not refusing. i am just saying that i cant compare it with the A310 data because they are all long gone to the scrapyard
so hard to find data to compare it with

but feel free to try it, if you have a spare A310-300 and an A350 handy. would be glad to hear the results!

[Continental Sky]

Well, I love these investigations, and I decided to give it a try... It looks to me like DanDan is right, consumption from datasheet does not comply with route data.

I purchased two sets of A310-300 / A350-900 and A350-100, and I assigned them exactly the same route. One set SFO-EWR, started with route image 0, and second set IND-SEA, started with RI 100, as I already had a flight there. Departure times are 0600, 0800 and 1000, TAT 120 minutes for A310, 150 minutes for A350.

Route SFO-EWR:
A310-300, age 13 yrs, fuel consumption (fc) 5,420 kg/hr, age factor (af) 2.5%
A359, age 4, fc 5,340, af 0.9%
A35K, age 9, fc 5,820, af 1.8%.

Based on these data, and given they flew exactly the same route, one would expect consumption to be very similar or somewhat higher for A350. However, it is not the case.

I checked route details three times over period of ~18 days, and here is fuel cost:
A310-300: varies between ~34 and 41 k USD.
A359: 20-26 k USD.
A35K: 18-24 kUSD

Route IND-SEA:
A310-300, age 14 yrs, fc 5,310 kg/hr, af 2.9%
A359, age 1, fc 5,340, af 0.2%
A35K, age 1, fc 5,820, af 0.1%.

The results for fuel cost are similar:
A310-300: 25-27 k USD.
A359: 16-18 k USD.
A35K: 14-16 kUSD

So, consumption of A310-300 on both routes is some 50-60% higher, although factory data do not justify that. Moreover, it also seems that consumption of A359 is higher than that of A35K, although factory data suggest the opposite.

Load factor was slightly different for all these flights, but I don't think it can make such a drastic difference, we're talking about 10-20 pax and ton or two of cargo, it cannot increase consumption 50%.

If anyone wants to dig the data further, all screenshots (data for all 6 planes and 3 x 6 route details) are available at https://www.mediafire.com/file/1sr3ld8v6lwrh55/310_vs_350.zip/file Header is visible in route details, so you can see the time it was taken.

I will keep these planes as they are, so I'm open for any further request for testing if needed.

[groundbum2]

don't forget to adjust for speed, A350s spend less time in the air.

I still need to investigate in TMT why A340-600s are using less than A330-800neos, it shouldn't be the case. Same route.

Simon

[Continental Sky]

Indeed, I didn't take it into account, thanks, but it's 0.85 vs 0.79 mach, too small methinks.

Flight time SFO-EWR
A310: 12:00 (05:30 + 06:30)
A350: 11:25 (05:20 + 06:05)

Flight time IND-SEA
A310: 09:05 (04:50 + 04:15)
A350: 08:40 (04:35 + 04:05)

So that's 5% longer flight time, still cannot explain this difference.

[schro]

Did you adjust for time to reach cruise altitude?

[Continental Sky]

Of course not.  Can it really account that much, it can be additional few pcts, not more?

[Continental Sky]

I still need to investigate in TMT why A340-600s are using less than A330-800neos, it shouldn't be the case. Same route.

Simon

Errrrm, that's not good news, I have 100 of 338 and 339 neos on order, in AG, and now you tell me I'd have fared better if I opted for A340, which are cheaper, and also available on UM... 

[groundbum2]

my oops, the newer planes use a lot less fuel, a few extended EGLL-WSSS stats below, all Eastbound so not into the wind...

340-500 6500kg/hr

   Y: 153   Y: 100%   CL: 74 kg           CL: 1.6%   114 770 kg
   C: 63   C: 100%   CS: 106 kg   CS: 0.6%   
   F: 16           F: 100%         
   Y: 153   Y: 100%   CL: 70 kg           CL: 1.6%   114 762 kg
   C: 63   C: 100%   CS: 100 kg   CS: 0.6%   
   F: 16           F: 100%         
   Y: 153   Y: 100%   CL: 80 kg           CL: 1.8%   114 783 kg
   C: 63   C: 100%   CS: 114 kg   CS: 0.7%   
   F: 16           F: 100%         
   Y: 153   Y: 100%   CL: 76 kg           CL: 1.7%   114 774 kg
   C: 63   C: 100%   CS: 108 kg   CS: 0.6%   
   F: 16           F: 100%         
   Y: 153   Y: 100%   CL: 80 kg           CL: 1.8%   114 783 kg
   C: 63   C: 100%   CS: 114 kg   CS: 0.7%   
   F: 16   F: 100%         
               
A330-900neo 5090 kg/hr
   Y: 216   Y: 100%   CL: 74 kg           CL: 3.2%   98 656 kg
   C: 70   C: 100%   CS: 106 kg   CS: 3.1%   
        F: 12           F: 100%         
   Y: 216   Y: 100%   CL: 70 kg           CL: 3.1%   98 656 kg
   C: 70   C: 100%   CS: 100 kg   CS: 2.9%   
   F: 12           F: 100%         
   Y: 216   Y: 100%   CL: 80 kg           CL: 3.5%   98 656 kg
   C: 70   C: 100%   CS: 114 kg   CS: 3.3%   
   F: 12           F: 100%         
   Y: 216   Y: 100%   CL: 76 kg           CL: 3.3%   98 656 kg
   C: 70   C: 100%   CS: 108 kg   CS: 3.2%   
   F: 12           F: 100%         
   Y: 216   Y: 100%   CL: 80 kg           CL: 3.5%   98 656 kg
   C: 70   C: 100%   CS: 114 kg   CS: 3.3%   
   F: 12           F: 100%         
               
A330-800neo 4890 kg/hr
   Y: 108   Y: 100%   CL: 79 kg           CL: 2%   94 876 kg
   C: 91   C: 100%   CS: 113 kg   CS: 0.8%   
   F: 24           F: 100%         
   Y: 108   Y: 100%   CL: 83 kg           CL: 2.2%   94 876 kg
   C: 91   C: 100%   CS: 119 kg   CS: 0.8%   
   F: 24           F: 100%         
   Y: 108   Y: 100%   CL: 73 kg           CL: 1.9%   94 876 kg
   C: 91   C: 100%   CS: 104 kg   CS: 0.7%   
   F: 24           F: 100%         
   Y: 108   Y: 100%   CL: 71 kg           CL: 1.8%   94 876 kg
   C: 91   C: 100%   CS: 102 kg   CS: 0.7%   
   F: 24           F: 100%         
               
A340-600 6610
   Y: 236   Y: 93.7%   CL: 75 kg           CL: 1.3%   123 580 kg
   C: 56   C: 100%   CS: 111 kg   CS: 0.5%   
   F: 16           F: 100%         
   Y: 252   Y: 100%   CL: 79 kg           CL: 1.3%   124 994 kg
   C: 56   C: 100%   CS: 113 kg   CS: 0.5%   
   F: 16           F: 100%         
   Y: 229   Y: 90.9%   CL: 71 kg           CL: 1.2%   122 951 kg
   C: 56   C: 100%   CS: 102 kg   CS: 0.5%   
   F: 16           F: 100%         
   Y: 235   Y: 93.3%   CL: 74 kg           CL: 1.2%   123 487 kg
   C: 56   C: 100%   CS: 107 kg   CS: 0.5%   
   F: 16     F: 100%         
   Y: 233   Y: 92.5%   CL: 74 kg           CL: 1.2%   123 309 kg
   C: 56   C: 100%   CS: 105 kg   CS: 0.5%   
   F: 16           F: 100%         

[Sami]

Let me know the route numbers you have for both planes and I can check the actual usage (kg/lbs) from the database directly.

[Continental Sky]

Sure, here they are, it's Modern Times, airline Kovacev Do, based in IND.

A310-300:
DJ43005 /06
DJ43015 /16

A350-900:
DJ43007 /08
DJ43013 /14

A350-1000:
DJ43009 /10
DJ43011 /12

[Continental Sky]

And please note, it was not me who reported bug, I was just bored enough to "investigate" it... 

[DanDan]

And please note, it was not me who reported bug, I was just bored enough to "investigate" it... 

thanks for the effort.

 to me the numbers were just weird, when i saw how much the fuel consumption dropped for my company, but by then the 24 year old A310s were already scrapped.