Qatar Airways: Go Slow To Save Fuel?

[libya 115]

I flew Qatar Airways a few days ago LONDON-DOHA . The journey time was 6 h 22 mins

I flew Qatar Airways DOHA-BANGKOK on the same journey, time 7 hours 13 minutes

I have travelled on numerous occassions from DOHÁ/DUBAI to Bangkok and the journey time has ALWAYS been 5.5 hours or 6.0 hours.

Plus: Onboard the aircraft, no journey time was mentioned by the pilots AND the display journey map was not functioning. (Showing flight times)

Am I paranoid or is this the beginning of airlines to slow down flights in order to save jet fuel?

[tw25rw]

I'm not sure it would work like that. I'm pretty sure the engines are designed to cruise at their most efficient speed. Going more than a little bit faster or slower would use more fuel, a bit like a car being in the wrong gear.

Whenever I've flown London-BKK not-stop, it's always 12 hours+ so I would suspect 11.5 hours with a stop wasn't right.

[londonthai]

very much depends on the wind speed, but usually the captain do keep informed, even at the beginning of the flight. There is possibility you flough the different, longer route to avoid storm or the plane was overloaded with cargo

[libya 115]

very much depends on the wind speed, but usually the captain do keep informed, even at the beginning of the flight. There is possibility you flough the different, longer route to avoid storm or the plane was overloaded with cargo

I was thinking about cargo. But does that slow a plane down? Or just use more fuel? Surely there are weight limits?

Maybe the storm avoidance route is more likely.

But never on a Middle East-Bangkok route, has it taken so long.

[warwick7735]

Hello

This sounds very much like flying into a headwind, airliners always fly at optimum speed and altidude, airspeed will always remain the same, but if your heading into say a 30mph headwind, your ground speed will be 30mph slower. Over a 6 hour flight thats 180miles you have lost, this will add time to your journey.

Also when your flying Easterly you arrive sooner because the earth is rotating towards you, But flying Westerly you are chasing the earth. So LHR-BKK is usually 11.5hrs, BKK-LHR is 12 hrs.

If fuel keeps on increasing it wont be long before they start using gliders

Hope that helps

[Carib]

Yup, could be headwind, but airlines also fly slightly slower ( not all of them yet) and they will not try to make up for lost time. It would mean flying faster.

If this goes on we will be towed to the runway and they will start up the engines there..

[IMA_FARANG]

I flew Qatar Airways a few days ago LONDON-DOHA . The journey time was 6 h 22 mins

I flew Qatar Airways DOHA-BANGKOK on the same journey, time 7 hours 13 minutes

I have travelled on numerous occassions from DOHÁ/DUBAI to Bangkok and the journey time has ALWAYS been 5.5 hours or 6.0 hours.

Plus: Onboard the aircraft, no journey time was mentioned by the pilots AND the display journey map was not functioning. (Showing flight times)

Am I paranoid or is this the beginning of airlines to slow down flights in order to save jet fuel?

I don't think slowing the airplane down would save fuel anyhow.

Most flights that go with the prevailing Jet Stream winds gain speed = shorter travel time traveling with the Jet Stream. Going the opposite way they are going against the Jet Stream = longer travel time. That's why the times west to east are usually faster than east to west. Also, it makes a difference on the altitude they fly at. There are usually lower winds at higher altitudes. Usually if a flight is being delayed due to headwinds they will request a higher altitude to gain speed...if the air traffic control people will allow it. Sometimes, usually flying over land areas, a higher altitude may not be allowed (you have to stay in the approved air traffic corridors).

For obvious reasons an airplane with a lot of cargo/luggage is heavier on takeoff. More fuel must be used for takeoff.

I've been on a flight going against a strong Jet Stream headwind. It took us 1.5 hours longer than normal for that flight.

Most times the pilots try to keep within schedule, including climbimg in altitude if possible to stick to the schedule.

p.s. Just to illustrate the Thai flight from Athens to BKK nonstop is 9 hours 50 minutes going from Athens to BKK, but is given as 10 hours 30 min nonstop from BKK to Athens. That is due to prevailing jet Stream...tailwind from Athens to BKK, and head wind BKK to Athens.

Edited August 9, 2008 by IMA_FARANG

[Carib]

Slowing the aircraft down does save fuel, but slowing down shouldnot be looked upon as something dramatic.

Each flight ( talking for southwest air now) about 6-8 minutes longer and not increasing power to make up for head wind, or lost time due to traffic control, or otherwise is expected to save about $ 42 million this year. I am talking fleetwide here.

Edited August 9, 2008 by Carib

[onzestan]

I flew Qatar Airways a few days ago LONDON-DOHA . The journey time was 6 h 22 mins

I flew Qatar Airways DOHA-BANGKOK on the same journey, time 7 hours 13 minutes

I have travelled on numerous occassions from DOHÁ/DUBAI to Bangkok and the journey time has ALWAYS been 5.5 hours or 6.0 hours.

Plus: Onboard the aircraft, no journey time was mentioned by the pilots AND the display journey map was not functioning. (Showing flight times)

Am I paranoid

Yes !!!

onzestan

[lomatopo]

I flew Qatar Airways a few days ago LONDON-DOHA . The journey time was 6 h 22 mins

I flew Qatar Airways DOHA-BANGKOK on the same journey, time 7 hours 13 minutes

I have travelled on numerous occassions from DOHÁ/DUBAI to Bangkok and the journey time has ALWAYS been 5.5 hours or 6.0 hours.

Plus: Onboard the aircraft, no journey time was mentioned by the pilots AND the display journey map was not functioning. (Showing flight times)

Am I paranoid or is this the beginning of airlines to slow down flights in order to save jet fuel?

Not paranoid, maybe just tired and so unable to do any sort of basic math or accurately read a clock, on your numerous previous trips?

Scheduled flight time for DOH-BKK on QR is 7:00 (seven hours and zero minutes). 7:13 seems reasonable; 5:30 or 6:00 does not.

[libya 115]

I flew Qatar Airways a few days ago LONDON-DOHA . The journey time was 6 h 22 mins

I flew Qatar Airways DOHA-BANGKOK on the same journey, time 7 hours 13 minutes

I have travelled on numerous occassions from DOHÁ/DUBAI to Bangkok and the journey time has ALWAYS been 5.5 hours or 6.0 hours.

Plus: Onboard the aircraft, no journey time was mentioned by the pilots AND the display journey map was not functioning. (Showing flight times)

Am I paranoid or is this the beginning of airlines to slow down flights in order to save jet fuel?

Not paranoid, maybe just tired and so unable to do any sort of basic math or accurately read a clock, on your numerous previous trips?

Scheduled flight time for DOH-BKK on QR is 7:00 (seven hours and zero minutes). 7:13 seems reasonable; 5:30 or 6:00 does not.

International flight schedules add 40 minutes as a matter of course. As I said, I have travelled the Middle East-Bangkok route more than one hundred times in the last eight years and have never experienced such a lengthy flight time. Considering that fuel prices are higher, maybe Qatar Airways are flying slower to save money.

Special Notice for ONZESTAN (see above) please refrain from unhelpful missives and redirect (them) to the Walloon forum.

[lomatopo]

Like I said I just think you're off by an hour, or maybe otherwise confused. Maybe you were late leaving and that threw you off? Airlines and flight crew have flight plans and adhere to ATC requirements. Often pilots have to estimate arrival at a particular beacon as requested by ATC controllers in order to maintain optimum flow. Pilots can request directional vector deviations due to weather, and vertical deviations due to turbulence. Sometimes these can contribute to increased flight times. While there is some leeway I'd say that on a flight like DOH-BKK you could see an additional six (6) minutes if they pilots chose to fly a bit slower to save fuel. This obviously cannot explain your observation.

Scheduled flight time, block to block (not wheels-up/touch-down), for DOH-BKK on QR is seven (7) hours and zero minutes.

QR610 DOH 08:00 08 Aug 08:07 08 Aug BKK 19:00 08 Aug [19:11 08 Aug] On time

QR612 DOH 20:45 08 Aug 20:45 08 Aug BKK 07:45 09 Aug 07:46 09 Aug Arrived

[onzestan]

Dear libya115.

You asked a question and I replied.

If you cannot help yourself from interpreting this as unhelpfull missives then that's your problem.

Anyway this is the second time that you try to insult me about being a Flemish extremist, which in both cases have no bearing on the topic involved.

I do not accept that.

onzestan

[Chivas]

Am booked on qatar shortly through to Bkk out of Heathrow.

Scheduled airtime is 6 hour 55 minute to Doha, and 7 hour Doha to BKK

Chivas

[libya 115]

Dear libya115.

Anyway this is the second time that you try to insult me about being a Flemish extremist, which in both cases have no bearing on the topic involved.

I do not accept that.

onzestan

Thank you for your valuable input about Qatar Airways. I am sorry if you thought I was insulting you about being a Flemish extremist. Good luck to you and your futile and risible cause.

Any further views and considerations regarding Qatar Airways will be gratefully received.

Libya 115

Edited August 9, 2008 by libya 115

[sibeymai]

There is only a limited capability to alter the aircraft's speed while cruising as the aerodynamics require the aeroplane to maintain a speed within a relatively small band for any given altitude to maintain optimum performance and control. I guess flying at the lower end of the band would save some fuel but would not alone add to the travel time to the extent in the OP's post. Expect headwinds or deviation from shortest route the most likely reasons. Even air traffic control routing at departure or arrival can contribute to variations in travel times. Weight of the aircraft is not a factor.

[Naam]

There is only a limited capability to alter the aircraft's speed while cruising as the aerodynamics require the aeroplane to maintain a speed within a relatively small band for any given altitude to maintain optimum performance and control. I guess flying at the lower end of the band would save some fuel but would not alone add to the travel time to the extent in the OP's post. Expect headwinds or deviation from shortest route the most likely reasons. Even air traffic control routing at departure or arrival can contribute to variations in travel times. Weight of the aircraft is not a factor.

it is a HUGE BIG factor! best example is that Thai discontinued the extreme long haul flight to New York because of the extra fuel that has to be carried.

[Naam]

quote: "Airlines, whose largest expense is now fuel, are taking action, and they are doing more than cutting flights to save fuel; they are actually "going over their planes with a fine tooth comb and tossing anything that isn't absolutely necessary" in a desperate bid to save weight and fuel. Here are some examples:

US Airways is chucking meal carts and replacing them with models that are 12 pounds lighter. They've also tossed the glassware in first class in favor of less jet-set but lighter plastic cups. Carriers also are pulling magazine racks, trash compactors and ovens...American Airlines has all but called in Jenny Craig to shave weight from its fleet, pulling in-seat phones and their heavy wiring, removing lavatory power converters and investing in lighter silverware for business class passengers

So does all this make a difference?

The airlines sure seem to think so. US Airways claims that its "lighter beverage carts will save $1.7 million in annual fuel costs," and "American expects to cut fuel consumption by 111 million gallons through its weight reduction efforts."

[Carib]

Delta is changing the seats for ones which are about 4 pound lighter, but weight is not a factor??

Every kg or pound has got to be taken and kept up there, and that costs fuel. I absolutely donot understand how someone can say that weight is not a factor, it is THE factor .

[lomatopo]

I think this thread is more about flying the aircraft more slowly in order to save fuel, and whther that could be responsible for the OP experiencing a 7:13 journey when s/he has been more use to a 5:30 - 6:00 journey. So for the purposes of this specific discussion weight is not a factor, at least as far as I can determine. Aircraft have a MTOW so it's not like you can somehow overload the aircraft and that causes it fly more slowly. Obviously just about anyone with half a brain understands that transporting more weight requires more fuel, so not really much need to state the obvious.

[sibeymai]

There is only a limited capability to alter the aircraft's speed while cruising as the aerodynamics require the aeroplane to maintain a speed within a relatively small band for any given altitude to maintain optimum performance and control. I guess flying at the lower end of the band would save some fuel but would not alone add to the travel time to the extent in the OP's post. Expect headwinds or deviation from shortest route the most likely reasons. Even air traffic control routing at departure or arrival can contribute to variations in travel times. Weight of the aircraft is not a factor.

it is a HUGE BIG factor! best example is that Thai discontinued the extreme long haul flight to New York because of the extra fuel that has to be carried.

Naam, I did not say that weight was not a factor of fuel consumption, simply that weight is not a factor which would cause the aeroplane to fly slower. The aircraft can maintain the designed airspeed regardless of whether it is empty or at maximum takeoff weight.

[libya 115]

Thank you everyone for input so far.

I find this a very interesting topic. It seems to me beyond doubt that the weight (mass) that the aircraft carries will have a direct result on the total amount of fuel used. I am also sure that deliberately reducing airline speed reduces fuel consumption.

I would most like to hear the views of those with first-hand experience in the fuel/aircraft industry and those of you who have flown regularly from the Middle East to Bangkok.

I would stand by my point that flying time for me, in the past has always been 5.5 hours to maximum 6.0 hours. I would understand that weather or diversion would increase journey time, but also consider that the on-screen graphic was turned off and the pilot did not give the usual chat regarding travel time after boarding.

Maybe this was a 'one-off' but I am interested to hear other persons views.

[Bizz]

The time will come when we are charged by kg weight per passenger.ie over 100kgs surcharge on ticket.

I bet they are thinking about this already.

Im happy im under 100kgs.

[Ricardo]

I had a very similar experience, flying Qatar on LGW-DOH-BKK last week, when it was noticeable that the climb-out from Doha was very gentle, and seemed to end earlier than normal, although we too found the flight-data screen to be unavailable in the early stages of the flight. Got up to 39,000 feet by the end of the trip however.

Perhaps it is more economical on fuel, when operating with a full load, to take your time getting up to normal cruising-height ? Any of our more-technical members care to comment ?

Or perhaps weather-conditions or traffic-control considerations in the Gulf, were to blame ?

Anyway we were 20 minutes late out of Doha, but 45 minutes late into BKK, on our flight.

Yup, could be headwind, but airlines also fly slightly slower ( not all of them yet) and they will not try to make up for lost time. It would mean flying faster.

If this goes on we will be towed to the runway and they will start up the engines there..

Virgin have been planning trials of exactly this, to see how much fuel might be saved, pre-flight, they estimate sometimes taking up to 20 minutes from push-back to starting the take-off roll. Hope it works !

[enyaw]

Warwick is right because the earth rotates west to east alot of airlines when travelling in the other direction will fly the aircraft up and wait there while the earth rotates round till the airport your going to comes around and then slowly descend onto it. It saves a fortune in fuel and is much better for the enviroment, I for one support this and don't mind the extra few hours airtime.

A Garnet.

[Carib]

Warwick is right because the earth rotates west to east alot of airlines when travelling in the other direction will fly the aircraft up and wait there while the earth rotates round till the airport your going to comes around and then slowly descend onto it. It saves a fortune in fuel and is much better for the enviroment, I for one support this and don't mind the extra few hours airtime.

A Garnet.

Earth and it`s rotation has been a part of trip planning since the early days of long distance flights.

I think you are mixing a few things up here.

You don't mind "the extra hours air time". Well, I do because every hour up there costs money, earth rotating or not.

Aircraft will not just go up and wait until the next stop is underneath, and than land there.

The shortest route ( weather and traffic control allowing) will be used to get to a destination, and the earth rotation van be an advantage, just as it can be a disadvantage.

But staying up there longer is not very fuel/cost efficient.

[lomatopo]

Warwick is right because the earth rotates west to east alot of airlines when travelling in the other direction will fly the aircraft up and wait there while the earth rotates round till the airport your going to comes around and then slowly descend onto it. It saves a fortune in fuel and is much better for the enviroment, I for one support this and don't mind the extra few hours airtime.

A Garnet.

Earth and it`s rotation has been a part of trip planning since the early days of long distance flights.

I think you are mixing a few things up here.

You don't mind "the extra hours air time". Well, I do because every hour up there costs money, earth rotating or not.

Aircraft will not just go up and wait until the next stop is underneath, and than land there.

The shortest route ( weather and traffic control allowing) will be used to get to a destination, and the earth rotation van be an advantage, just as it can be a disadvantage.

But staying up there longer is not very fuel/cost efficient.

Please, please tell me that you two are not really serious? Let me guess, you think if you jump up in the air that the Earth moves beneath you? And that you land in a different spot? Clearly the educational system you've experienced has failed you.

Whether firmly earth-bound, or floating above the Earth (within the confines of the Earth's gravity), your speed relative to the earth remains constant at ZERO MPH/KPH. If you were floating in space outside the influence of Earth's gravity then yes, the Earth would move beneath you at ~ 700 MPH.

The rotation of the Earth has absolutely no influence on flght times east to west, west to east or north<->south.

[Carib]

Warwick is right because the earth rotates west to east alot of airlines when travelling in the other direction will fly the aircraft up and wait there while the earth rotates round till the airport your going to comes around and then slowly descend onto it. It saves a fortune in fuel and is much better for the enviroment, I for one support this and don't mind the extra few hours airtime.

A Garnet.

Earth and it`s rotation has been a part of trip planning since the early days of long distance flights.

I think you are mixing a few things up here.

You don't mind "the extra hours air time". Well, I do because every hour up there costs money, earth rotating or not.

Aircraft will not just go up and wait until the next stop is underneath, and than land there.

The shortest route ( weather and traffic control allowing) will be used to get to a destination, and the earth rotation van be an advantage, just as it can be a disadvantage.

But staying up there longer is not very fuel/cost efficient.

Please, please tell me that you two are not really serious? Let me guess, you think if you jump up in the air that the Earth moves beneath you? And that you land in a different spot? Clearly the educational system you've experienced has failed you.

Whether firmly earth-bound, or floating above the Earth (within the confines of the Earth's gravity), your speed relative to the earth remains constant at ZERO MPH/KPH. If you were floating in space outside the influence of Earth's gravity then yes, the Earth would move beneath you at ~ 700 MPH.

The rotation of the Earth has absolutely no influence on flght times east to west, west to east or north<->south.

Hold the horses, yes you are partly right and some parts absolutely right, but....

I was debunking the rotation theory, in the same way as it was stated. Didn't do a good job because I didn't take the air mass movement in to the whole thing. To me it is a just a fact that doesn't need much thought, and I should have explained better.

You are right to say that if you jump that you will land on the same spot. That is IF the air masses will allow you to do so. That is where the rotation theory comes in and the effect of it on the air masses .

It is a very complex picture. Ones lifting of the earth you are in a different medium , which by the rotation of the earth, and the effect gravity has on it, Will have a different movement than as a stationary mass of air. It will put you down on a different spot that you jumped from, if you went up high enough and stayed up there long enough.

To really get into the nitty gritty of it al look at the Coriolis effect, The hadley, Ferris and polar weather cells and if you want to fire a long range missile without it leaving earth`s gravity field also take the Etvos effect into consideration. ( I do this by heart so don't mind the spelling.).

So, yes the earth atmosphere moves together with the earth at the same speed, but the atmosphere has got a mind of its own, with the first push given by earth rotation. Usually very predictable under normal circumstances, hence shorter or longer flights depending on direction. It is an accepted `thing`, nobody really gives it a thought ones you are used to it.

FAA or Jar trained guys/girls don't even really grasp this theory, but just accept it and learn to live with it, and the place where they are confronted with it is usually the met office. Earth rotation all of a sudden doesn't really exist anymore, they are just looking at the result of it. ( of course there is more )

Endless discussions take place about this, especially the ones who are in traing to become pilots or have a job related to aviation or other use of the earth`s airspace. Some will just give up and accept that the earth rotates and that is takes more time to get from A to B than the other way around, depending where you are. I don't discuss this either, I stopped thinking about it and just accepted.

Thanks for the comment Lomatopo, at least someone was really awake.

[lomatopo]

Warwick is right because the earth rotates west to east alot of airlines when travelling in the other direction will fly the aircraft up and wait there while the earth rotates round till the airport your going to comes around and then slowly descend onto it. It saves a fortune in fuel and is much better for the enviroment, I for one support this and don't mind the extra few hours airtime.

A Garnet.

Earth and it`s rotation has been a part of trip planning since the early days of long distance flights.

I think you are mixing a few things up here.

You don't mind "the extra hours air time". Well, I do because every hour up there costs money, earth rotating or not.

Aircraft will not just go up and wait until the next stop is underneath, and than land there.

The shortest route ( weather and traffic control allowing) will be used to get to a destination, and the earth rotation van be an advantage, just as it can be a disadvantage.

But staying up there longer is not very fuel/cost efficient.

Please, please tell me that you two are not really serious? Let me guess, you think if you jump up in the air that the Earth moves beneath you? And that you land in a different spot? Clearly the educational system you've experienced has failed you.

Whether firmly earth-bound, or floating above the Earth (within the confines of the Earth's gravity), your speed relative to the earth remains constant at ZERO MPH/KPH. If you were floating in space outside the influence of Earth's gravity then yes, the Earth would move beneath you at ~ 700 MPH.

The rotation of the Earth has absolutely no influence on flght times east to west, west to east or north<->south.

Hold the horses, yes you are partly right and some parts absolutely right, but....

I was debunking the rotation theory, in the same way as it was stated. Didn't do a good job because I didn't take the air mass movement in to the whole thing. To me it is a just a fact that doesn't need much thought, and I should have explained better.

You are right to say that if you jump that you will land on the same spot. That is IF the air masses will allow you to do so. That is where the rotation theory comes in and the effect of it on the air masses .

It is a very complex picture. Ones lifting of the earth you are in a different medium , which by the rotation of the earth, and the effect gravity has on it, Will have a different movement than as a stationary mass of air. It will put you down on a different spot that you jumped from, if you went up high enough and stayed up there long enough.

To really get into the nitty gritty of it al look at the Coriolis effect, The hadley, Ferris and polar weather cells and if you want to fire a long range missile without it leaving earth`s gravity field also take the Etvos effect into consideration. ( I do this by heart so don't mind the spelling.).

So, yes the earth atmosphere moves together with the earth at the same speed, but the atmosphere has got a mind of its own, with the first push given by earth rotation. Usually very predictable under normal circumstances, hence shorter or longer flights depending on direction. It is an accepted `thing`, nobody really gives it a thought ones you are used to it.

FAA or Jar trained guys/girls don't even really grasp this theory, but just accept it and learn to live with it, and the place where they are confronted with it is usually the met office. Earth rotation all of a sudden doesn't really exist anymore, they are just looking at the result of it. ( of course there is more )

Endless discussions take place about this, especially the ones who are in traing to become pilots or have a job related to aviation or other use of the earth`s airspace. Some will just give up and accept that the earth rotates and that is takes more time to get from A to B than the other way around, depending where you are. I don't discuss this either, I stopped thinking about it and just accepted.

Thanks for the comment Lomatopo, at least someone was really awake.

After all that I can only hope and pray you have nothing to do with the safety of any airline passengers as you appear, from your post(s), to be way too close to "Le Bong".

I admit that I sometimes forget how many truly ignorant ("I stopped thinking...", the definition of ignorance) people there are in our World. Thanks for the reminder. Good luck with that jumping thing!

[cophen]

Do aircraft fly Great Circle routes or do they have to flit from beacon to beacon?

Edited August 25, 2008 by cophen