Fuel tankering...How to?
Thread Starter
Join Date: Apr 2012
Location: In Space
Posts: 683
Likes: 0
Received 0 Likes
on
0 Posts
Fuel tankering...How to?
Hello guys!
In my very short career I've only experienced fuel tankering twice, and the second time was the other day.
I was thinking is there an easy way of calculating the fuel uplift?
The company asked us if we can tanker fuel back to base, so doing that we had to punch some numbers.
I was told we can use the following formula:
MLW+Trip fuel-MZFW = max theoretical fuel
But wouldn't that be only if we are LDW limited, what if we was TOW limited?
I was in Malaga and they were using RWY 31, so the on the day conditions only allowed a RTOM of 73.4, bearing in mind our ZFW and LDW was a bit more so it ment we was RTOM limited.
I know this is a silly question to some, and proberly very easy to work out but fuel tankering can be very easy or go horribly wrong if you uplifted to much!
Any advice would be appreciated,
Thank you.
In my very short career I've only experienced fuel tankering twice, and the second time was the other day.
I was thinking is there an easy way of calculating the fuel uplift?
The company asked us if we can tanker fuel back to base, so doing that we had to punch some numbers.
I was told we can use the following formula:
MLW+Trip fuel-MZFW = max theoretical fuel
But wouldn't that be only if we are LDW limited, what if we was TOW limited?
I was in Malaga and they were using RWY 31, so the on the day conditions only allowed a RTOM of 73.4, bearing in mind our ZFW and LDW was a bit more so it ment we was RTOM limited.
I know this is a silly question to some, and proberly very easy to work out but fuel tankering can be very easy or go horribly wrong if you uplifted to much!
Any advice would be appreciated,
Thank you.
Join Date: Mar 1999
Location: Australia
Age: 53
Posts: 207
Likes: 0
Received 0 Likes
on
0 Posts
You're correct, that is only the case for landing weight limited. If you are TOW limited it is even easier, just subtract your ZFW from the MTOW, add your taxi fuel and that is the max you can uplift. Whatever you don't use you've tanked!
It gets a bit more complex if you want to tank a specific amount as you have to consider the fuel burn required to carry the fuel. Also depends on why you want to tank, if its to save money by buying it cheap don't go to close to a limiting weight and this may give you heartburn with MTOW or MLW. If you want to avoid a refuel to get a faster turnaround at the next port don't cut it too close on the fuel on arrival as the time to top up may chew up most of the time your trying to save.
It gets a bit more complex if you want to tank a specific amount as you have to consider the fuel burn required to carry the fuel. Also depends on why you want to tank, if its to save money by buying it cheap don't go to close to a limiting weight and this may give you heartburn with MTOW or MLW. If you want to avoid a refuel to get a faster turnaround at the next port don't cut it too close on the fuel on arrival as the time to top up may chew up most of the time your trying to save.
Join Date: May 2011
Location: FL400
Posts: 398
Likes: 0
Received 0 Likes
on
0 Posts
The maximum fuel is your MTOW minus ZFW. Then make sure that you are not going to exceed your MLW on arrival (you are limited by one or the other) and that the LDR is not greater than the LDA.
There are some other considerations - trip fuel is now going to be increased (the 737 burns 2.5% of the weight of the tankered fuel in additional trip fuel every hour). Also, if you are doing a turnaround at the other end, cold-soaked fuel frost can be an issue.
There are some other considerations - trip fuel is now going to be increased (the 737 burns 2.5% of the weight of the tankered fuel in additional trip fuel every hour). Also, if you are doing a turnaround at the other end, cold-soaked fuel frost can be an issue.
Per Ardua ad Astraeus
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes
on
0 Posts
......and lastly, don't 'ace' the calculation to the exact kg, since even allowing for the fact that you might NOT burn your contingency fuel (remember that in the MLW calculations!! - AND allow for route short-cuts) IF you actually burn slightly over the calculated trip fuel getting to destination - leaving you a few kg 'short' - an uplift of a few hundred kg at destination can turn out to be very expensive and wipe out any tankering 'savings', since many refuellers impose a minimum uplift/penalty for small uplifts.
Tankering DOES require significant thought. Do NOT be pressured by company into taking a heavier a/c into a 'problem' runway - digging your ship out of the over-run will not be particularly cost saving
Tankering DOES require significant thought. Do NOT be pressured by company into taking a heavier a/c into a 'problem' runway - digging your ship out of the over-run will not be particularly cost saving
Guest
Posts: n/a
You mentioned your formula where MLW and MZFW is taken care off.
Yes you need to take care of MTOW too.
And do not forget the "hidden" limit, that of NORMAL Take Off fuel from your Destination.
Otherwise you may find yourself doing Tankering with "expencive" fuel !!!
or tankering when it is not required.
Yes you need to take care of MTOW too.
And do not forget the "hidden" limit, that of NORMAL Take Off fuel from your Destination.
Otherwise you may find yourself doing Tankering with "expencive" fuel !!!
or tankering when it is not required.
Thread Starter
Join Date: Apr 2012
Location: In Space
Posts: 683
Likes: 0
Received 0 Likes
on
0 Posts
Thanks guys this is great!
Can the formula MLW - EStimated landing weight work?
The reason we were tankering fuel, was because at our home base there was a possible fuel shortage due to a fuel leak in the pipes at the place where the tankers pick up the fuel..Emirates and BA had priority over the fuel!
At my company on our OFP we have a fuel penalty of per 100kg = 5
If I remember correctly on the day using RW 31 our RTOM was 73.1
Estimated TOM 70t
Required minimum block fuel of 10t
So am I correct in thinking I could uplift 3.1 extra fuel?
Can the formula MLW - EStimated landing weight work?
The reason we were tankering fuel, was because at our home base there was a possible fuel shortage due to a fuel leak in the pipes at the place where the tankers pick up the fuel..Emirates and BA had priority over the fuel!
At my company on our OFP we have a fuel penalty of per 100kg = 5
If I remember correctly on the day using RW 31 our RTOM was 73.1
Estimated TOM 70t
Required minimum block fuel of 10t
So am I correct in thinking I could uplift 3.1 extra fuel?
Last edited by B737900er; 30th Sep 2012 at 09:17.
B737900er:
First, establish your most limiting weight for take-off which will be the lowest of:
a) performance RTOW
b) structural RTOW of aircraft
c) landing weight RTOW which = MLW + trip fuel to destination
Take the most limiting of the above and subtract the actual ZFW to give a fuel that can be carried ( + you may add taxi fuel )
Finally ensure that this fuel uplift does not exceed the fuel you actually require for the subsequent sector - no point in "over tankering".
The above technique will always work and save any embarrassment.
First, establish your most limiting weight for take-off which will be the lowest of:
a) performance RTOW
b) structural RTOW of aircraft
c) landing weight RTOW which = MLW + trip fuel to destination
Take the most limiting of the above and subtract the actual ZFW to give a fuel that can be carried ( + you may add taxi fuel )
Finally ensure that this fuel uplift does not exceed the fuel you actually require for the subsequent sector - no point in "over tankering".
The above technique will always work and save any embarrassment.
Last edited by Meikleour; 30th Sep 2012 at 12:01. Reason: Spelling
Thread Starter
Join Date: Apr 2012
Location: In Space
Posts: 683
Likes: 0
Received 0 Likes
on
0 Posts
Meikleour
Thanks for that it has confirmed my thinking is on the correct page.
Regarding your statement about the 'over tanking'. I would need to take more fuel than what is required for the sector or I wouldn't be tanking?
If the sector required 10t and I had 3 tonnes to play with I would need to take more than minimum i.e 10 t to class it as tankering right?
Or am I missing something?
I appreciate the feedback and its answering the questions that keep popping into my head.
Regarding your statement about the 'over tanking'. I would need to take more fuel than what is required for the sector or I wouldn't be tanking?
If the sector required 10t and I had 3 tonnes to play with I would need to take more than minimum i.e 10 t to class it as tankering right?
Or am I missing something?
I appreciate the feedback and its answering the questions that keep popping into my head.
He means that you only need to tanker enough fuel to cover the fuel for the next sector immediately after the 'tankering' sector ie tanker on leg 1, but only tanker enough fuel to be able to meet leg 2's requirements even though you may have additional capacity to carry more. No use carrying more fuel than will be needed.
Bear in mind the advice others have given: Tankering to cover leg 2 but finding you landed after leg 1 with not quite enough fuel for leg 2 can be expensive due minimum fuel purchase requirements.
Another option, if you don't have sufficient capacity to tanker for the whole of leg 2 *and* have min. purchase requirements at the intermediate landing point, is to plan to arrive from the tankering leg needing just the min. fuel purchase amount for leg 2. I've done that plenty of times in the pistons & turboprops I fly.
Bear in mind the advice others have given: Tankering to cover leg 2 but finding you landed after leg 1 with not quite enough fuel for leg 2 can be expensive due minimum fuel purchase requirements.
Another option, if you don't have sufficient capacity to tanker for the whole of leg 2 *and* have min. purchase requirements at the intermediate landing point, is to plan to arrive from the tankering leg needing just the min. fuel purchase amount for leg 2. I've done that plenty of times in the pistons & turboprops I fly.
In Cathay we sometimes carry 3 sector fuel!! ( Cat C )
Boy isn't that a fun calculation to make.
Agree with meikleour
First, establish your most limiting weight for take-off which will be the lowest of:
a) performance RTOW
b) structural RTOW of aircraft
c) landing weight RTOW which = MLW + trip fuel to destination
Don't forget to check your MLW at the first destination, it may not be the a/c maximum LW.
When calculating the tankering fuel required:-
Second sector fuel required + First sector burn off + Taxi in fuel ( at 1st destination ) + APU burn in transit ( at first destination ) = total fuel required for 2 sectors.
Boy isn't that a fun calculation to make.
Agree with meikleour
First, establish your most limiting weight for take-off which will be the lowest of:
a) performance RTOW
b) structural RTOW of aircraft
c) landing weight RTOW which = MLW + trip fuel to destination
Don't forget to check your MLW at the first destination, it may not be the a/c maximum LW.
When calculating the tankering fuel required:-
Second sector fuel required + First sector burn off + Taxi in fuel ( at 1st destination ) + APU burn in transit ( at first destination ) = total fuel required for 2 sectors.
Last edited by nitpicker330; 1st Oct 2012 at 01:09.
Join Date: Jul 2000
Location: Everywhere
Posts: 783
Likes: 0
Received 0 Likes
on
0 Posts
As nitpicker has said.
I would normally:
Decide the total block fuel for Sector 2. Add 100kg to be sure you have this on stand. It should cover your APU as well.
Add the TAXI + TRIP from Sector 1, adjusted slightly to account for the extra burn per hour and realistic enough to make sure you don't eat in to your Sector 2 block fuel.
Check your TOW is acceptable.
Edit: for an A320!
I would normally:
Decide the total block fuel for Sector 2. Add 100kg to be sure you have this on stand. It should cover your APU as well.
Add the TAXI + TRIP from Sector 1, adjusted slightly to account for the extra burn per hour and realistic enough to make sure you don't eat in to your Sector 2 block fuel.
Check your TOW is acceptable.
Edit: for an A320!
Last edited by The African Dude; 1st Oct 2012 at 07:23.
Yeah & get the math right ! I picked up a flight outa Mumbai to Bahrain & noticed we had, about, ten tons more than we needed. Stopped laughing when I was called in to the Office to explain ! Previous Captain was well connected & the matter was laughed off. Oh, heady days of cheap fuel. Remember too that it can COST more to tank lots of fuel than can reasonably saved by doing so. Finally, in my last two widebodies, MLW was always the decider. MLW +burn resulted in the lowest RTOW, even on Manilla to BAH.
Last edited by Gordomac; 1st Oct 2012 at 08:47.
Join Date: Jul 1999
Location: UK
Posts: 166
Likes: 0
Received 0 Likes
on
0 Posts
Are you flying the B737 800? If so the maximum fuel you would want to land with is 5400kg total to avoid wing icing problems at destination with the sort of sector length you are talking about (AGP - UK). To allow for direct routes etc maybe a landing fuel of 5000kg is a good planning figure. Burn + 5000 + taxy, making suitable adjustments for max take off and landing masses.
Thread Starter
Join Date: Apr 2012
Location: In Space
Posts: 683
Likes: 0
Received 0 Likes
on
0 Posts
Matey
Yes it's the 800. The only reason we tankard was just In case we had issues at our landing base. When I think about tanking fuel home was a bit pointless now you guys have mentioned 'minimum fuel uplift' etc.
Join Date: Apr 2005
Location: UK
Posts: 459
Likes: 0
Received 0 Likes
on
0 Posts
Tankering ???
Sorry for the drift, but.
Unless Tankering is reqd for a good reasons(not just cost of fuel) it's a dead loss for planet green and safety.
Aircraft operating at higher weights than reqd don't just use more fuel, it's all the other bits, the only good point that comes to mind is holding/diversion options can be more flex.
I hear of some airlines tankering on very long sectors to max weights allowed, crazy.
Not forgetting a big trap, tankering where you hope no fuel will be uplifted at subject airport and being just a little short on the next flight for various reasons, this can make for a flight to remember.
Safe flying to all.....
Sorry for the drift, but.
Unless Tankering is reqd for a good reasons(not just cost of fuel) it's a dead loss for planet green and safety.
Aircraft operating at higher weights than reqd don't just use more fuel, it's all the other bits, the only good point that comes to mind is holding/diversion options can be more flex.
I hear of some airlines tankering on very long sectors to max weights allowed, crazy.
Not forgetting a big trap, tankering where you hope no fuel will be uplifted at subject airport and being just a little short on the next flight for various reasons, this can make for a flight to remember.
Safe flying to all.....