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Australian Airlines Slow down to save fuel
Australian airlines slow down to save fuel http://www.straitstimes.com/STI/STIM...01_01_0001.jpg http://www.straitstimes.com/STI/STIMEDIA/common/c.gif Qantas (above), one of the world's major airlines, which dwarfs Jetstar's annual fuel consumption of 580 million litres a year, issued a terse statement on which it would not elaborate. -- PHOTO: AP http://www.straitstimes.com/STI/STIMEDIA/common/c.gif SYDNEY - SOME Australian airlines are flying slowly to save fuel as oil prices surge to record highs, it was revealed on Friday. Like motorists trying to economise, pilots are easing back on the throttle, national carrier Qantas and its budget offshoot Jetstar said. Dropping the average flying speed on their Airbus A320s by about 20 kilometres per hour would save millions of dollars a year, Jetstar spokesman Mr Simon Westaway said. 'We are conducting a trial of flying the aircraft at slightly lower airspeeds,' he said. Airlines have a cost index from 0-99, in which '99 is what is usually simply called putting your foot to the floor - that's essentially maximum fuel burn. 'Zero is the minimum, so its essentially how you ride the accelerator,' he said. Jetstar was testing dropping its cost index from 30 to 10 as the price of aviation fuel soars along with oil, which hit all-time highs of more than US$135 a barrel this week. 'Essentially it means a reduction in speed of around 10 knots or 20 kilometres an hour over the course of a journey.' The slower speeds would add about six minutes to a trans-Australia flight from Melbourne to Perth, which normally takes between three-and-a-half to four hours depending on direction and other factors, Mr Westaway said. The extra few minutes do not appear to have raised the ire of passengers, who probably have not noticed among all the factors that can slow a journey, from delays ahead of takeoff to circling before getting the go-ahead to land. On long-haul flights, those minutes would multiply and mark a strange reversal of the ambition for ever-faster connections around the world since the invention of flying. But with oil supplies finite and price rises appearing limitless, jet pilots driving like cash-strapped commuters appear to be a sign of the times. Qantas, one of the world's major airlines, which dwarfs Jetstar's annual fuel consumption of 580 million litres a year, issued a terse statement on which it would not elaborate. 'Qantas has used variable speed flight plans within its schedules over the last two years as a fuel conservation initiative. 'This practice has led to fuel savings and lower carbon emissions without any significant impact on flight times.' Qantas announced Thursday that it would increase international air fares to counter the impact of rising fuel costs by about 4.0 per cent from June 4, after a 3.0 per cent hike earlier this month. -- AFP Source: Straitstimes.com.sg |
Time to dust off thoughts of getting towed out?
Actually, would there be any saving in starting one (or two, in a 3- or 4-holer) at push-back and then firing up the remainder closer to take-off? Or, setting take-off sequence when a/c are still on the stand and only giving taki clearance when it's likely that the departures won't have to queue for ages (or at least dispersing around the field to free-up stands - I have in mind KJFK and the 60-min-plus evening rush waits, probably more than Australian fields)? That is, it seems to me to be folly to give taxi clearance to, say, five departures in five minutes when there is at least a 1-min gap between take-offs; if all taxi out in a line, you are straight away looking at a 10-min delay for the last one off. |
i only ever went to JFK once but i think QF was looking at a procedure to shut one down on the taxi out and restart (obviously) a bit later due to the extended delays always experienced there. Shutting one down on the 744 for taxi in has been around for quite some time....if anyone remembered to do it! :O
It's probably not worth the hassle for the very occasional extended ground delay post pushback in Australia. Tow out on the other hand is an idea that has been thrown around previously. I'm sure there is a cross over point at which the economics of it start to look good. i wonder where that point is. Ironic that the guy who tows the aircraft out gets paid a ****e load more than a VAustralia 'Cruise F/O'. :eek: :E |
Cruise flight speed schedules have been based on airplane weight for long distance flights since the B707 was in service!
That is, the heavier the AUW, the faster the cruise speed, and vice versa. The result being that as the airplane used up fuel, the cruise speed schedule decreased, effectively maintaining a constant wing angle of attack, the designed cruise AOA. Only a small decrease (or increase) in this designed speed for weight can be tolerated, after which drag increases, forcing up the power/fuel required to maintain that speed. Much better to move the CG aft in cruise, and maintain the design cruise speed. Engine manufacturers recommend minimum engine operating times prior to takeoff power being applied, and indicate that higher peak EGT will be incurred when the warmup time is lower. Now isn't that totally contrary to the whole reasoning for using derated/reduced power settings when you can, to lower that peak EGT and extend the service life of the engine!! The warmup time is around three minutes at or near idle for most engines! Anyway, if the Airbus went any slower, they will have to start celebrating birthday parties on longer trips, and quoting the arrival time by the date. Cheers...FD...:bored: |
We do that now on the A345 LAX and EWR flts:ok:
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Go hard into the headwind. Back off in the tailwind. Has some come up with a better idea?
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Fly slow Go Low
Your MNT(Mach No will be less). I will keep u at a lower level
and give the faster guys the higher levels or the optimum levels. As a Ctler I do not want u to hog a good level. What will be the MNT if you are going to fly slow? I observe that JSA always does a slow climb.Why is this so? Replies appreciated.:ok: |
If you guys/gals are going to do an economy[slower] cruise/descent please let the controller know early.
The flow is looking at the sequence from around 250 miles out and it is usually set by 200 miles. An econ cruise descent can cost 2-3 minutes at the 40mile gate and this can create a hole in the sequence and concertina the following traffic. If the flow doesn't discover this until you are at 150 miles then it can be too late to fix. Worse, you may be instructed to increase speed thereby burning the fuel you saved. If we know early then you might drop back one in the sequence and land at the same time but 10 following aircraft might save 2-3 minutes each. Just tell the controller "for the flow we are doing econ descent 250kts".:ok: AA |
amberale,
with respect, its not upto us to let you know, the company should have already done this. If they havent then you should place an incident report as they are not compliant with the speed schedule as submitted to ASA for standardisation. I have a problem with the company altering speed schedules without atc knowledge as I am sympathetic to your problem. But we fly the aircraft the way the company tells us to. In other words, its not our fault. |
This is most likely a dumb question, but on heavily loaded flights at upper altitudes are we not taking a chance of pushing into "coffin corner" and risking a high altitude stall?
As I said, probably a dumb question but do recall several American carriers getting 727s into such stall conditions and doing significant damage to moveable control surfaces rescuing the beast. The paperwork - Ooooh the paperwork!! Best all EWL |
The flow is looking at the sequence from around 250 miles out and it is usually set by 200 miles. And as for YPPH:( Dubai? One controller wants you at barber pole and the next wants you at min clean, if not min approach:{ |
For Christx sake, noone is going to be cruising in coffin corner and noone is going to be descending at any other speed than that agreed between the Company and the ATC authorities. End of story.
It's a slight adjustment to cost index. ATCs didn't have any clue as to what CI was applied previously and they don't need to know the new one either. It's nothing. |
dodgybrothers I gotta say I don't understand the point you are trying to make.
amberale, with respect, its not upto us to let you know, the company should have already done this. If they havent then you should place an incident report as they are not compliant with the speed schedule as submitted to ASA for standardisation. I have a problem with the company altering speed schedules without atc knowledge as I am sympathetic to your problem. But we fly the aircraft the way the company tells us to. In other words, its not our fault. It is this mach number that ATC use to estimate you eta at various points along your route. I think the point that was being made was that if your flight plan uses CI 40 and you decide to fly at CI 0 (zero) because you are running early and decide to save some fuel, ATC want to know what your revised Mach number is so that they can factor it in when working out the traffic flow. The flight plan may have indicated that you were going to cruise at M.80 but after entering CI 0 (zero) into the FMC you slow down to cruise at M.77. That is a problem for ATC. That was the point being made. |
It's nothing. Talking to one Airbus Captain today he wondered if it really saved money, might save some fuel, 100kg here and there, but how does the cost of longer engine / airframe hours, wages and other flow on effects add up? Maybe cheaper to stick it to her! J:ok: |
In a four engine jet why not shut an engine down in the cruise?
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Talking to one Airbus Captain today he wondered if it really saved money, might save some fuel, 100kg here and there, but how does the cost of longer engine / airframe hours, wages and other flow on effects add up? As fuel becomes more expensive, min COST speed moves towards min fuel burn speed, ie better to use a lower Cost Index. Ah but which cost index to use? That is the question to be worked out by the "experts" in your company's flight dispatch dept. |
I did hear a Jet* flight day before yesterday requesting a .77 cruse into YMLT i beileve.
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My company (UK based) on the 757 and 767 is currently using a cost index of 18.
Gives a .78 still air cuise on the 757 and .785 on the 767. At current prices it will save 650,000 USD per airframe on average this year. It adds around 12 minutes to a London-Vancouver sector, and about 8 minutes London-New York. More flight duty pay though:E |
Dodgyb,
all we get from your FP at the console is an IAS [yep, 400-450kts] The flow calculates your feeder fix time[40nm] using real data[your speed and known winds] and adds a known time from that point to the threshold. That time is then used to establish the sequence order. The speed schedule that the 3 majors in Oz have supplied us with is that you will fly fast if you are late, profile if you are on time and slowly if you are early. We are to expect you to fly the same aircraft at different speeds at all times.:confused: Chimbu, unfortunately I don't think the SY flow starts before 6am. We are trialling some long range stuff from the noc shop but some problems still exist. Eclan, sometimes the flow will group a series of flights from one direction and ask for them in trail, usually 10nm at 40nm from destination. This equates to a 2 minute sequence and can save 30secs per flight. If you are #2 and catching #1 at 50kt gs then the sector controller has to do something to maintain the spacing.speed or vector for extra miles. Perhaps the preceding crew are operating in econ mode. Disclaimer ; my details are for Brisbane flow but the speed problem [ie what speed are you going to do] is across the board. I'm not accusing anyone of foul play, just trying to help us all.:) AA |
777 300 ER points
Some interesting findings:
-on this aircraft, a recent study compared (real life, not software predictions) data colected from flights operated either on company suggested CIs, on the lower 30s, wich translates into an average M.83 crz speed with other operated on typically LRC, CI around 180, giving M.84. Given comparable TOW, atmospheric conditions, routes and aircrafts the only difference in operating at the lower CI is EXTENDED FLIGHT TIME! The practice contradicts Boeing software predictions. Flying at a CI lower than say 150-180 does not actually provide any significant fuel savings. On the other hand, keeping the cruise around M.84 saves time without burning more fuel, thus reducing the overal trip costs. These are cold FACTS, not guessing, with enough data to provide a definite trend. Any clues? |
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