When does it burn fuel to carry fuel?
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Of course you agree with the nimrod, you dunce. You're him...reposting under a new name after you managed to get banned (again)...posting to agree with yourself.
Truly pathetic.
Truly pathetic.
Lemurian & kijangnim,
I'd never heard of the K factor so I stand educated. *
We usually left tankering decisions to you management chaps anyway
As far as extra burn is concerned we kept it simple:
3% x hour for extra loaded.
4% x hour for extra planned arrival.
and thanked our lucky stars we didn't work for Ryanair.
( * Edited to say except for K in calculating SAT from TAT)
I'd never heard of the K factor so I stand educated. *
We usually left tankering decisions to you management chaps anyway
As far as extra burn is concerned we kept it simple:
3% x hour for extra loaded.
4% x hour for extra planned arrival.
and thanked our lucky stars we didn't work for Ryanair.
( * Edited to say except for K in calculating SAT from TAT)
Last edited by Basil; 6th Sep 2008 at 12:49.
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Greetings,
Basil, thanks for your remarks, management takes these decisions simply because they have zee information i.e., the fuel price, nevertheless using the K factor (transport factor) is higly beneficial for tankering, for ofloading and so on
HAPPY LANDING
Basil, thanks for your remarks, management takes these decisions simply because they have zee information i.e., the fuel price, nevertheless using the K factor (transport factor) is higly beneficial for tankering, for ofloading and so on
HAPPY LANDING
Sun worshipper
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Hello, Basil
The "K factor" for each flight is on the CFP, therefore available to the Flight Deck crew.
As I cannot make public the documents of my airline, I went on the Net to find some text on the subject and Lo! and Behold! there is one, from the Airbus series of "Getting to grips with..." I found in a Smart Cockpit !
You probably know all the fuel conservation techniques it talks about but the chapter 4.5 deals with "fuel for transportation".
Have a look :
Getting to Grips With Fuel Economy
Click on the screen icon to load.
Best regards.
The "K factor" for each flight is on the CFP, therefore available to the Flight Deck crew.
As I cannot make public the documents of my airline, I went on the Net to find some text on the subject and Lo! and Behold! there is one, from the Airbus series of "Getting to grips with..." I found in a Smart Cockpit !
You probably know all the fuel conservation techniques it talks about but the chapter 4.5 deals with "fuel for transportation".
Have a look :
Getting to Grips With Fuel Economy
Click on the screen icon to load.
Best regards.
Lemurian,
Thanks for the URL. How did I get through a career without that website?
Better not try to imagine what Lemurian and Hugh Dibley of BA & Airbus Industrie would say
So I guess the K formula is an elegant way of doing the calculation instead of piecemeal, as I'd have done before my moment of enlightenment.
Thanks for the URL. How did I get through a career without that website?
Better not try to imagine what Lemurian and Hugh Dibley of BA & Airbus Industrie would say
So I guess the K formula is an elegant way of doing the calculation instead of piecemeal, as I'd have done before my moment of enlightenment.
Last edited by Basil; 7th Sep 2008 at 11:52. Reason: Correcting poor grammar
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Yes, that website is priceless.
As for my aviation culture, a first officer taught me yesterday how to use the sidestick. I thought that in order to turn, I only needed the rudder pedals...
regards.
As for my aviation culture, a first officer taught me yesterday how to use the sidestick. I thought that in order to turn, I only needed the rudder pedals...
regards.
Just had a go at sidestick in a 'bus sim a few weeks ago.
Some interesting control laws and responses for a simple lad who's always had a bit of string leading to the wiggly bits
Some interesting control laws and responses for a simple lad who's always had a bit of string leading to the wiggly bits
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LeMurian
The Airbus transport factor deals only with the additional fuel required to carry fuel, it doesnt account for the cost of carrying that fuel in terms of extra stress on the aircraft/brakes/thrust reversers/engines, therefore its not ideal when you are trying to make a financial assessment on tankering fuel....
Mutt
The Airbus transport factor deals only with the additional fuel required to carry fuel, it doesnt account for the cost of carrying that fuel in terms of extra stress on the aircraft/brakes/thrust reversers/engines, therefore its not ideal when you are trying to make a financial assessment on tankering fuel....
Mutt
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Surely the KEY aspect here is not so much HOW MUCH extra you take
but more HOW LONG you carry it for!
In other words for a short haul pilot like moi......
If I take half a tonne extra- and my sector time is 65 mins- I'll have pretty much all of my 500kg extra when I get near the airfield-which I can then use to deal with whatever it was that I took it for.
Or land with it unburnt! And damn little of it wasted!
( I know it's a different arguament if you carry it for 13 hours- most of it is gone when you arrive- so why take it?)
For short haul- I'm unconvinced that carrying a bit extra is very wasteful.
btw I was on a UK flight that diverted due to not having 15 mins holding fuel 10 days ago. Wonder what that cost?
but more HOW LONG you carry it for!
In other words for a short haul pilot like moi......
If I take half a tonne extra- and my sector time is 65 mins- I'll have pretty much all of my 500kg extra when I get near the airfield-which I can then use to deal with whatever it was that I took it for.
Or land with it unburnt! And damn little of it wasted!
( I know it's a different arguament if you carry it for 13 hours- most of it is gone when you arrive- so why take it?)
For short haul- I'm unconvinced that carrying a bit extra is very wasteful.
btw I was on a UK flight that diverted due to not having 15 mins holding fuel 10 days ago. Wonder what that cost?
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BarbiesBoyfriend,
If you burn 4% of your 500 kgs per flight, with x flights per day x 365 days per year, the numbers start to add up. So you cant look at one flight and say that its not worth it!
The longest sector that we tanker is 10 hours, we use 40% of the loaded tanker fuel to get it there. But with the cost differential between the two airports, its an excellent way to make money.
Mutt
If you burn 4% of your 500 kgs per flight, with x flights per day x 365 days per year, the numbers start to add up. So you cant look at one flight and say that its not worth it!
The longest sector that we tanker is 10 hours, we use 40% of the loaded tanker fuel to get it there. But with the cost differential between the two airports, its an excellent way to make money.
Mutt
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Mutt
My FO is fat. I have to carry him 4 flights a day, 635 days a year. It all adds up you know.
Maybe we should put the crews on a diet and just employ size 8 hosties..
Everything 'adds up'.
20kg of gas wasted (by tankering 500kg for an hour) is a great trade off for the peace of mind (and the range of available options) that it provides.
20kg FFS.
Now I've thought about it a bit more, thanks to you & your 4% advice, and realised how little is wasted, I shall continue with my present practice and worry about it even less than before- if that's possible!
My FO is fat. I have to carry him 4 flights a day, 635 days a year. It all adds up you know.
Maybe we should put the crews on a diet and just employ size 8 hosties.
.Everything 'adds up'.
20kg of gas wasted (by tankering 500kg for an hour) is a great trade off for the peace of mind (and the range of available options) that it provides.
20kg FFS.
Now I've thought about it a bit more, thanks to you & your 4% advice, and realised how little is wasted, I shall continue with my present practice and worry about it even less than before- if that's possible!
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Surely the KEY aspect here is not so much HOW MUCH extra you take
but more HOW LONG you carry it for!
but more HOW LONG you carry it for!
On a short leg, tankering really depends on what we need to meet our landing weights...our landing weight is 200,000 lbs less than our takeoff weight...so generally tankering fuel isn't an option in the first place for us for a short trip.
Then, looking at the requirements at the landing field, if we need to increase our brake setting and experience higher brake wear as a result, we may easily have eaten the cost of the tankered fuel or any savings thereof, before we even leave the runway. Add to that increased turn around times due to hotter brakes due to the heavier landing weight (depending on runway, of course)...we may have just shot ourselves in the foot by losing time that could have been spent flying revenue freight, instead of letting our brakes cool.
It's a tradeoff, but I don't think it's nearly so simple as saying a short leg justifies tankering the load.
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Hello, Mutt
The Airbus transport factor deals only with the additional fuel required to carry fuel, it doesnt account for the cost of carrying that fuel in terms of extra stress on the aircraft/brakes/thrust reversers/engines, therefore its not ideal when you are trying to make a financial assessment on tankering fuel....
In all fairness, you are right but in real terms, we are talking of relatively low increases on the aircraft weight.
Add the fact that tankering over more than three sectors - short haul - is not recommended on most airlines, we are really talking about peanuts.
Example :
Landing 4000 kg of extra fuel, lets say that our landing weight increased from 56 to 60 T.
The landing speeds have one up from 125 kt - 64.3 m/s² - to 130 kt -66.9 m/s².
The kinetic energy upon landing therefore has gone from 115.8 MJ to 134.8 MJ, an increase of 16% either taken by braking energy or brake/reverse energy.
I really don't see a dramatic increase of operational constraints here, as seen by SNS3Guppy.
Tankering on a long haul sector, as I demonstarted is only worth the trouble if the fuel prices are drastically different.
One of the more challenging - and interesting - aspects of our job is that we make decicions based on reason and experience. Going to LHR at six a.m wth the computed fuel seem rather idiotic as a lengthy hold is very likely...How much extra fuel for holding then ? Depends whether you know the ATC controller or you're a pessimist. Or just experienced enough on the sector...
I personally have seen on occasions people who took off 30 min behind me having to divert while I made it after a 50 minute racetrack pettern over BIG...
Last edited by Lemurian; 12th Sep 2008 at 18:07. Reason: spelling, as usual...
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but in real terms, we are talking of relatively low increases on the aircraft weight
Mutt
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More in line with Mutt's response, I look at departure and destination fuel, and tanker acordingly to get the trip cost(down and back) to the minimal cost). Always hated to leave a jet parked overnight fuel of fuel, tires tend to set,(thump thump thump on taxi the next day)wet wings have a higher preponderance to leak...not to mention overall higher landing weights, longer rollouts, and more brake and tire wear...
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I look at departure and destination fuel, and tanker acordingly to get the trip cost(down and back) to the minimal cost). Always hated to leave a jet parked overnight fuel of fuel, tires tend to set,(thump thump thump on taxi the next day)wet wings have a higher preponderance to leak...not to mention overall higher landing weights, longer rollouts, and more brake and tire wear...
"Preponderance to leak?" Your computer leaks? Wings with fuel tend to leak, do they? Do you simulated airplanes have holes in the wings?
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I was curious about the cost to the airport if aircraft are tankering fuel. I tried two scenarios. One was a small airport, with 737-800 tankering 2.5 hours fuel – say 6 tonnes. The second was a large airport with a mix of 777, 767 and 737. The 777 was tankering in 30 tonnes, the 767 was tankering 20 tonnes, and the 737 was tankering 6 tonnes.
The design of airport pavements (runways etc) typically assumes that the aircraft arrives lighter than it departs: i.e. it fuels up at the airport. Thus the arrivals are at light weights and the departures are at heavy weights. Since the damaging effect of a load is a function of [weight to the power 4], a heavier aircraft is much much more damaging than a lighter aircraft. If everyone is tankering, then effectively you are doubling the number of heavy flights and cutting the lighter flights to zero.
For both scenarios, the design life of the pavement was cut from 20 years to 12-13 years. If the airport is charging a landing charge per tonne, then simplistically the charge should rise by about 50%. Of course, the cost of pavement deterioration and replacement is only a small percentage of the costs that the landing charge covers, so the true increase should be less.
However since most airports today are run either as shopping centres or industrial parks, I would be surprised if many airports even knew about what happens on the runway.
The design of airport pavements (runways etc) typically assumes that the aircraft arrives lighter than it departs: i.e. it fuels up at the airport. Thus the arrivals are at light weights and the departures are at heavy weights. Since the damaging effect of a load is a function of [weight to the power 4], a heavier aircraft is much much more damaging than a lighter aircraft. If everyone is tankering, then effectively you are doubling the number of heavy flights and cutting the lighter flights to zero.
For both scenarios, the design life of the pavement was cut from 20 years to 12-13 years. If the airport is charging a landing charge per tonne, then simplistically the charge should rise by about 50%. Of course, the cost of pavement deterioration and replacement is only a small percentage of the costs that the landing charge covers, so the true increase should be less.
However since most airports today are run either as shopping centres or industrial parks, I would be surprised if many airports even knew about what happens on the runway.
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If one bases the arrival and landing weight of each aircraft on it's maximum landing weight, then the matter is irrelevant...it's not going to be any heavier if it's tankering fuel, if the stress analysis is based on each operation at it's maximum weight. "Heavy" and "light" are relative. We generally always depart at maximum takeoff weight, and land at or around maximum landing weight...what percentage of the fuel load is tankered, then, is irrelevant to the considerations of runway or taxiway or apron life.
For both scenarios, the design life of the pavement was cut from 20 years to 12-13 years. If the airport is charging a landing charge per tonne, then simplistically the charge should rise by about 50%.