Fuel contents on approach...
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Fuel contents on approach...
Hi
Just wondering what are the typical fuel contents (%) in the left, centre, and right tanks of an airliner, taking into consideration possible G/As and diversions from missed appraoches.
Thanks
Just wondering what are the typical fuel contents (%) in the left, centre, and right tanks of an airliner, taking into consideration possible G/As and diversions from missed appraoches.
Thanks
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Depends on the airliner - specifically, what the subsequent fuel burn in the event of a diversion is likely to be.
Normally, we plan to land at our destination with fuel for a go-around and diversion to our alternate airport, in order to land there with 'final reserve fuel', defined by JAR-OPS as enough gas to fly for 30 minutes at 1500' in the landing config at MLW. The actual fuel on board for a normal landing will depend mainly on how far away the alternate is, since final reserve fuel is relatively constant for a particular type (about 1200-1500 kg for the B737/A320/321).
We can elect to use our alternate fuel whilst holding for destination, however, under certain conditions (that's the subject of a different thread!).
Ideally, the centre tank will be empty on landing - normal procedure is to leave as much fuel in the wing tanks for as long as possible. The main reason for this is to permit the weight of the fuel to relieve the structural load on the wings due to lift. So on my types (B737/A320/A321) centre tank fuel is always burnt first.
To answer your question more specifically, my current type (B737) could have between 650kg (after a diversion) and 1500Kg (typical landing fuel at destination) in each wing tank. Zero fuel in the centre.
I'm sure you will get a different answer from pilots of aircraft with more complex fuel systems (long-haul aircraft, particularly)
Normally, we plan to land at our destination with fuel for a go-around and diversion to our alternate airport, in order to land there with 'final reserve fuel', defined by JAR-OPS as enough gas to fly for 30 minutes at 1500' in the landing config at MLW. The actual fuel on board for a normal landing will depend mainly on how far away the alternate is, since final reserve fuel is relatively constant for a particular type (about 1200-1500 kg for the B737/A320/321).
We can elect to use our alternate fuel whilst holding for destination, however, under certain conditions (that's the subject of a different thread!).
Ideally, the centre tank will be empty on landing - normal procedure is to leave as much fuel in the wing tanks for as long as possible. The main reason for this is to permit the weight of the fuel to relieve the structural load on the wings due to lift. So on my types (B737/A320/A321) centre tank fuel is always burnt first.
To answer your question more specifically, my current type (B737) could have between 650kg (after a diversion) and 1500Kg (typical landing fuel at destination) in each wing tank. Zero fuel in the centre.
I'm sure you will get a different answer from pilots of aircraft with more complex fuel systems (long-haul aircraft, particularly)
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Thanks for a very informative reply Gary.
I am actually looking for typical approx. percentage of fuel in the left/right tanks.
Would 20% in each L/R tank seem reasonable?
I am actually looking for typical approx. percentage of fuel in the left/right tanks.
Would 20% in each L/R tank seem reasonable?
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It can not be defined in terms of percentage. Percentage of what? %age of maximum take off fuel based upon aircraft structural MTOW or based upon Regulated TOW for the day, upon the fuel load at departure (usually less than max on short haul) etc. etc.
Minimum landing fuel is an absolute figure, based upon the requirements listed above by Gary.
On a day when your alternate is just 30 nautical miles away it might be 5%. On a day when it is 300 miles away it will be much more.
Minimum landing fuel is an absolute figure, based upon the requirements listed above by Gary.
On a day when your alternate is just 30 nautical miles away it might be 5%. On a day when it is 300 miles away it will be much more.
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Alright, to keep you quiet:
Wing tanks 30% full
Centre tank 0% full
B737 Wings hold 4500-4600kg each.
Centre tank holds something like 8000kg (not totally sure, 'cause I've never filled it).
We're talking B737 Classic here, not NG or BBJ.
Can't remember Airbus figures.
Why do you ask??
Possibly the key to understanding this is to recognise that airliners, unlike a C152 or similar, do not just fill up the tanks before a flight. Every kg of fuel we carry is extra weight, which increases our fuel burn, which increases our fuel requirement.
We start by building up a minimum fuel requirement for the sector, beginning with minimum fuel at destination (including reserves & diversion fuel) and add on 'trip' fuel (planned in-flight fuel) and then some for start-up and taxy. Then any extra we require on top of that is at the crew's discretion - maybe to account for known delays into a particular airport due to traffic or Wx.
So you can see that depending on the (very variable) conditions of the day, a % remaining could change quite a bit.
And the thing that really affects the '%', is how big the damn tanks are to start with, not the fuel left on board!
Wing tanks 30% full
Centre tank 0% full
B737 Wings hold 4500-4600kg each.
Centre tank holds something like 8000kg (not totally sure, 'cause I've never filled it).
We're talking B737 Classic here, not NG or BBJ.
Can't remember Airbus figures.
Why do you ask??
Possibly the key to understanding this is to recognise that airliners, unlike a C152 or similar, do not just fill up the tanks before a flight. Every kg of fuel we carry is extra weight, which increases our fuel burn, which increases our fuel requirement.
We start by building up a minimum fuel requirement for the sector, beginning with minimum fuel at destination (including reserves & diversion fuel) and add on 'trip' fuel (planned in-flight fuel) and then some for start-up and taxy. Then any extra we require on top of that is at the crew's discretion - maybe to account for known delays into a particular airport due to traffic or Wx.
So you can see that depending on the (very variable) conditions of the day, a % remaining could change quite a bit.
And the thing that really affects the '%', is how big the damn tanks are to start with, not the fuel left on board!
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In the A340, with a maximum fuel of approximately 150 tonnes and a normal arrival fuel of around 8 tonnes, the percentages are something like this:
Outer wing tanks: 0%
Inner wing tanks: 10%
Centre tank: 0%
Trim tank: 0%
I assume this is a Flight Sim related question?
Outer wing tanks: 0%
Inner wing tanks: 10%
Centre tank: 0%
Trim tank: 0%
I assume this is a Flight Sim related question?
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10 on 10 to Scroggs for managing to identify the motive behind my initial question (MS Flight Sim!)
Thanks for all the responses guys...they have been very informative.
Just to clarify Gary, when you say:
Wing tanks 30% full
Is that 30% in each tank, or 15% in each tank?
Cheers!
Thanks for all the responses guys...they have been very informative.
Just to clarify Gary, when you say:
Wing tanks 30% full
Is that 30% in each tank, or 15% in each tank?
Cheers!
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It would appear, from various previous posts on these august forums, that IF the concerned airline was BA, using long haul aircraft, especially if the concerned Commander decided (poorly, IMO) to continue on three (in a four engine aircraft) for long overwater distances, that the simple answer would be... sweet **** all.
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G'day 411A,
Give up? Vous? Well to keep you occupied...
I'll give you two routes and some traffic.
B744 no 1 flies LAX-J9/J107-NORRA-J107-VBI-SCAJ-JELCO-62/60-62/40-59/20-56/10-UN561-BEL-UB3-WAL-B3-HON-ATS-EGLL. A ball park of wind/delays etc is that your spread of journey time is 9.75-10.25hrs. Make it the latter.
B744 no 2 flies JFK-MERIT-HFD-PUT-WITCH-ALLEX-DCT YQX-KOBEV-50/50-52/40-53/30-53/20-5315-UG1/G1-CPT-ATS-EGLL. A ball park of wind/delays etc is that your spread of journey time is 9.75-10.25hrs. Make it the latter.
Both LAX and JFK aircraft roll at 380 tonnes and the two part question is as follows. a) How much fuel would you put in at the start for each aircraft and how much do you expect to have on arrival? b) nothing else changes except that the flight is accomplished from start to finish on three engines with the wind (and no delays) computed from the aforementioned 4-engine journey times planned at M0.86 cruise. To which level would you have to descend in ISA
conditions to completely exhaust fuel by LHR?
Give up? Vous? Well to keep you occupied...
I'll give you two routes and some traffic.
B744 no 1 flies LAX-J9/J107-NORRA-J107-VBI-SCAJ-JELCO-62/60-62/40-59/20-56/10-UN561-BEL-UB3-WAL-B3-HON-ATS-EGLL. A ball park of wind/delays etc is that your spread of journey time is 9.75-10.25hrs. Make it the latter.
B744 no 2 flies JFK-MERIT-HFD-PUT-WITCH-ALLEX-DCT YQX-KOBEV-50/50-52/40-53/30-53/20-5315-UG1/G1-CPT-ATS-EGLL. A ball park of wind/delays etc is that your spread of journey time is 9.75-10.25hrs. Make it the latter.
Both LAX and JFK aircraft roll at 380 tonnes and the two part question is as follows. a) How much fuel would you put in at the start for each aircraft and how much do you expect to have on arrival? b) nothing else changes except that the flight is accomplished from start to finish on three engines with the wind (and no delays) computed from the aforementioned 4-engine journey times planned at M0.86 cruise. To which level would you have to descend in ISA
conditions to completely exhaust fuel by LHR?
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\\flight is accomplished from start to finish on three engines with the wind (and no delays) computed from the aforementioned 4-engine journey times planned at M0.86 cruise. To which level would you have to descend in ISA
conditions to completely exhaust fuel by LHR?\\
G'day to you, enicalyth.
Well, for starters, completing the intended journey (in a four engine aircraft), from start to finish, on three would be irresponsible, in my opinion, IE: the intent of the concerned regulations are to expect the engine failure/shutdown well into the cruise, not from takeoff.
Now, I don't fly the B747-400, but I presently do fly the Lockheed TriStar, and if an engine failed in the cruise, the fuel consumption would be increased by 500kg/hr (same for the B707 in years gone by) and the resultant reduced altitude, provided the aircraft departed at max weight, would be in the vicinity of FL250.
You might well not find the winds at that altitude to your liking, so the journey time would certainly be longer as a result, not counting the reduced TAS in the cruise with one shut down/failed.
Therefore, a landing short of the destination might well be required, to enable an approach/landing with sufficient reserves for a diversion.
Those very long overwater journeys with an engine shut down/failed, with few enroute diversion fields available could well be...not very bright, IMHO.
It is not so much 'will the aeroplane do it', it becomes...'is it wise to do so.'
As always, Murphy's law is there to interfere...when you least expect it.
Just my opinion you understand, from much long haul practical experience in 3/4 engine heavy jet transport ops.
conditions to completely exhaust fuel by LHR?\\
G'day to you, enicalyth.
Well, for starters, completing the intended journey (in a four engine aircraft), from start to finish, on three would be irresponsible, in my opinion, IE: the intent of the concerned regulations are to expect the engine failure/shutdown well into the cruise, not from takeoff.
Now, I don't fly the B747-400, but I presently do fly the Lockheed TriStar, and if an engine failed in the cruise, the fuel consumption would be increased by 500kg/hr (same for the B707 in years gone by) and the resultant reduced altitude, provided the aircraft departed at max weight, would be in the vicinity of FL250.
You might well not find the winds at that altitude to your liking, so the journey time would certainly be longer as a result, not counting the reduced TAS in the cruise with one shut down/failed.
Therefore, a landing short of the destination might well be required, to enable an approach/landing with sufficient reserves for a diversion.
Those very long overwater journeys with an engine shut down/failed, with few enroute diversion fields available could well be...not very bright, IMHO.
It is not so much 'will the aeroplane do it', it becomes...'is it wise to do so.'
As always, Murphy's law is there to interfere...when you least expect it.
Just my opinion you understand, from much long haul practical experience in 3/4 engine heavy jet transport ops.
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I know 411A
G'day again to you.
Thank you for your reply. I know that just because you can do it does not mean to say that you should.
But I also have more than a shrewd guess that the fuel situation was not a case of running dry but more to do with conflicting readouts consequent on shutting an engine down.
My exam question you take in good part I am sure, you're a good sort judging by your posts.
For me as of 1st June 2005 I am parked up, retired. I don't feel as attached to the B744 as you do to the L1011 and I've always tried to stay away from Megajet vs Hairbrush controversy.
But boy would I love to sit down with you and rainboe and old smokey and J_T in my favourite bar, pour the beers and sit back to watch sparks fly.
Have a good day big fella!
Best rgds
the E
Thank you for your reply. I know that just because you can do it does not mean to say that you should.
But I also have more than a shrewd guess that the fuel situation was not a case of running dry but more to do with conflicting readouts consequent on shutting an engine down.
My exam question you take in good part I am sure, you're a good sort judging by your posts.
For me as of 1st June 2005 I am parked up, retired. I don't feel as attached to the B744 as you do to the L1011 and I've always tried to stay away from Megajet vs Hairbrush controversy.
But boy would I love to sit down with you and rainboe and old smokey and J_T in my favourite bar, pour the beers and sit back to watch sparks fly.
Have a good day big fella!
Best rgds
the E
