VB in the Wind Tunnel
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VB in the Wind Tunnel
Ok, please do not take this as a QF sling at VB, but I gotta know..
The scene: Anywhere there is a Jetstream.
The cast: Two plucky airliners battle the hurricane. One, wearing a White Rat is considerably lower than the other, 15-20000 feet in some extreme cases.
The red-adorned one is sitting at "optimum alt", but barely making headway.
The question is, why?
Sitting at optimum in a 180 knot headwind makes no sense when you can get 100 knots plus or more groundspeed cruising in the 20's. Your break-even fuel burn comes way down in such circumstances.
This also goes on to the punctuality question. I said in another thread that I regularly get around 85% departures on time but my arrival punctuality would be somewhat better than that by using various methods such as the one described above.
So why does VB do it? Surely it is costing them money.
Once again, not a dig, just wish to know.
PS: on another track, why do airlines always take DEPARTURE times as the punctuality yardstick? I am often early and it never seems to offset the late recorded departure. Who cares if you are 4 minutes late if you arrive 2 minutes early?
The scene: Anywhere there is a Jetstream.
The cast: Two plucky airliners battle the hurricane. One, wearing a White Rat is considerably lower than the other, 15-20000 feet in some extreme cases.
The red-adorned one is sitting at "optimum alt", but barely making headway.
The question is, why?
Sitting at optimum in a 180 knot headwind makes no sense when you can get 100 knots plus or more groundspeed cruising in the 20's. Your break-even fuel burn comes way down in such circumstances.
This also goes on to the punctuality question. I said in another thread that I regularly get around 85% departures on time but my arrival punctuality would be somewhat better than that by using various methods such as the one described above.
So why does VB do it? Surely it is costing them money.
Once again, not a dig, just wish to know.
PS: on another track, why do airlines always take DEPARTURE times as the punctuality yardstick? I am often early and it never seems to offset the late recorded departure. Who cares if you are 4 minutes late if you arrive 2 minutes early?
Nunc est bibendum
Sorry GT, I disagree. The customer likes to think that they are always right. Often though they need to be better educated. I don't see anyone attempting to do that! 
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G'day Borg. The company want us to as much as possible fly to the flight plan. That is, the cost index and flight level. Some of us look at the situation you describe above and throw on extra gas and fly lower to maintain the schedule. I don't like getting in 30 mins late if I departed on time and think it is very poor customer service. For justification we say turbulence was giving us grief etc, sure you get the picture. A lot of the younger guys don't think outside the box just yet.
I asked someone who reckons that they know, and this is what he said....
One significant reason why VB cruise higher is that fuel makes up a far greater percentage of the TRUE operating cost of the VB aeroplanes than it does in QF.
This is not because of the hedging policies that may or may not be in place at either operator, but because of the age of the aeroplanes and the contractual arrangements that exist for each aeroplane with regards maintenance and maintenance reserves.
For VB crew are a fixed cost vs a variable cost and as such don't enter into the equation, neither do lease standing charges per month.
The flight planning system optimises on the basis of cost figures input for fuel at each port and also maintenance per hour per airframe and based on those costs picks a level.
It isn't fool proof, particularly with really strong winds, but except for the extremes it mostly comes up with a cost effective altitude.
Here is a QF question - what do you guys get told about cost index and cruise speeds? We often see, as you have suggested, white aeroplanes steaming past at a great rate of knots, and the fuel burn must be horrendous - to say nothing about the noise in the pointy end!! - that isn't a swing at QF either, just an observation - I even heard a QF 800 down at 22 grand on Saurday - is that normal??
One significant reason why VB cruise higher is that fuel makes up a far greater percentage of the TRUE operating cost of the VB aeroplanes than it does in QF.
This is not because of the hedging policies that may or may not be in place at either operator, but because of the age of the aeroplanes and the contractual arrangements that exist for each aeroplane with regards maintenance and maintenance reserves.
For VB crew are a fixed cost vs a variable cost and as such don't enter into the equation, neither do lease standing charges per month.
The flight planning system optimises on the basis of cost figures input for fuel at each port and also maintenance per hour per airframe and based on those costs picks a level.
It isn't fool proof, particularly with really strong winds, but except for the extremes it mostly comes up with a cost effective altitude.
Here is a QF question - what do you guys get told about cost index and cruise speeds? We often see, as you have suggested, white aeroplanes steaming past at a great rate of knots, and the fuel burn must be horrendous - to say nothing about the noise in the pointy end!! - that isn't a swing at QF either, just an observation - I even heard a QF 800 down at 22 grand on Saurday - is that normal??
Nunc est bibendum
Dhd, it isn't abnormal. I've been across to Perth and the highest I got was 26K. Bumps was the main reason but better ground nm/kg was also not a bad trade off for getting in on time instead of an hour later for 35K. Out of time at the moment but will come back tomorrow.
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DH driver,
Without getting into a lecture on jet aircraft performance - I don't think I could remember it all anymore anyway - what it comes down to is specific ground range (SGR). And please, if I'm telling you to suck eggs, forgive me, but it does explain the answer to your question.
Going lower, under a very strong jetstream, may indeed send your fuel flow up, but you might also get a huge increase in groundspeed (maybe 60-100 knots on occasions). Specific ground range is a measure of ground miles covered per tonne of fule burnt, so if your groundspeed goes right up (even though your fuel flow has also increased) you may, in fact, be better off at the lower level. On SYD-PER flights, I remember a captain on the 747 telling me that he left late, got in early and burnt less gas going down low.
Last week SYD-MEL, we flew at FL240 for a headwind of 35 knots. The guys up high were getting 130 knot headwind. For a TAS of 480, this represents nearly a 20% increase in groundspeed. Therefore, you could afford a 20% increase in fuel flow and still break even for the sector. Even if it cost you fuel, you could possibly make up 8-9 minutes for a few hundred kilos of gas on a 1 hour sector. In QF we are not given restrictions on cruising levels - it is left up to us (so far) to manage the flight.
PS For all the conspiracy theorists, such tactics (in my experience) are not flown to get in front of our competitors - rather it is done to try to get back on schedule.
Without getting into a lecture on jet aircraft performance - I don't think I could remember it all anymore anyway - what it comes down to is specific ground range (SGR). And please, if I'm telling you to suck eggs, forgive me, but it does explain the answer to your question.
Going lower, under a very strong jetstream, may indeed send your fuel flow up, but you might also get a huge increase in groundspeed (maybe 60-100 knots on occasions). Specific ground range is a measure of ground miles covered per tonne of fule burnt, so if your groundspeed goes right up (even though your fuel flow has also increased) you may, in fact, be better off at the lower level. On SYD-PER flights, I remember a captain on the 747 telling me that he left late, got in early and burnt less gas going down low.
Last week SYD-MEL, we flew at FL240 for a headwind of 35 knots. The guys up high were getting 130 knot headwind. For a TAS of 480, this represents nearly a 20% increase in groundspeed. Therefore, you could afford a 20% increase in fuel flow and still break even for the sector. Even if it cost you fuel, you could possibly make up 8-9 minutes for a few hundred kilos of gas on a 1 hour sector. In QF we are not given restrictions on cruising levels - it is left up to us (so far) to manage the flight.
PS For all the conspiracy theorists, such tactics (in my experience) are not flown to get in front of our competitors - rather it is done to try to get back on schedule.
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I really can't believe all this nonsence!
I mean, if you guys gotta have this discussion, on this website, to work out whether you should fly at 35k into 150kts or go down to 22k into 50kts well, you know, you really should get another job!
I mean, if you guys gotta have this discussion, on this website, to work out whether you should fly at 35k into 150kts or go down to 22k into 50kts well, you know, you really should get another job!
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DHdriver (ignoring amos's little outburst for a bit)... QF used to operate on a fixed cost index for all 767 operations, but a few years ago moved to a variable cost index in an attempt to better match the conditions of the day to the scheduled flight time.
As KEG says, it is not unusual to cruise all the way to Perth in the 20's and it is not unusual to be actually flight planned in the 20's as well, leaving aside the judgement of the Captain for a bit.
Obviously there are two different schools of thought in operation here.
In relation to what you say about crew costs, QF crew costs are fixed for each domestic flight as well. Each flight is worked on a schedule based on historic data and the crew is paid accordingly no matter what the conditions of the day are. The only variable then comes down to flight time and concommitant maintenance costs, in which case the advantages of doing it faster are self-evident.
To sum it up, I still need to be convinced that VB are saving money doing it the way they do it.
Maybe there is something in the equation still to be canvassed here.
As KEG says, it is not unusual to cruise all the way to Perth in the 20's and it is not unusual to be actually flight planned in the 20's as well, leaving aside the judgement of the Captain for a bit.
Obviously there are two different schools of thought in operation here.
In relation to what you say about crew costs, QF crew costs are fixed for each domestic flight as well. Each flight is worked on a schedule based on historic data and the crew is paid accordingly no matter what the conditions of the day are. The only variable then comes down to flight time and concommitant maintenance costs, in which case the advantages of doing it faster are self-evident.
To sum it up, I still need to be convinced that VB are saving money doing it the way they do it.
Maybe there is something in the equation still to be canvassed here.
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Yep, the pax do notice on time departures and with often only 35 minute turn arounds on the 73's you can't do it without ontime arrivals as well.
Latest directives though seem to be making it harder and harder though. We were going to be able to get the final load sheet via ACARS on the taxi out, now we wait at the gate. TOW increases of more than 500kg now require a new T/O card even though it's inside the buffer. Talk also of 500kg less also requiring a new card to increase to derate. Could in the past call ready in the one minute cabin prep before T/O, now we have to wait for F/A's to be seated.
Enroute we are limited to 300kts on descent in the 800 as they don't trust us to not use speed brake over 300kts. VB seem to do as they please.
Now limited to 250 kts below 5000 feet, 210 kts at 12 nm and flap 5 speed (around 165kts) at G/S intercept, no such limit at VB I bet. In fact I've heard a number of stories of QF A/C, being infront and below VB, being slowed and vectored so that VB could go number one as ATC believe they are quicker.
Laughter rings in the ears, proffessional pilots - where?
I now hear many asking why bother, I think we will see more and more rats at 410K with VB in the wind tunnel.
Just doing it for the money now.
Latest directives though seem to be making it harder and harder though. We were going to be able to get the final load sheet via ACARS on the taxi out, now we wait at the gate. TOW increases of more than 500kg now require a new T/O card even though it's inside the buffer. Talk also of 500kg less also requiring a new card to increase to derate. Could in the past call ready in the one minute cabin prep before T/O, now we have to wait for F/A's to be seated.
Enroute we are limited to 300kts on descent in the 800 as they don't trust us to not use speed brake over 300kts. VB seem to do as they please.
Now limited to 250 kts below 5000 feet, 210 kts at 12 nm and flap 5 speed (around 165kts) at G/S intercept, no such limit at VB I bet. In fact I've heard a number of stories of QF A/C, being infront and below VB, being slowed and vectored so that VB could go number one as ATC believe they are quicker.
Laughter rings in the ears, proffessional pilots - where?
I now hear many asking why bother, I think we will see more and more rats at 410K with VB in the wind tunnel.
Just doing it for the money now.
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Yet again amos you astound us with your outbursts. There is a perfectly normal conversation going on here between the lads at DJ and QF. Please feel free to contribute something constructive and blow us away with some of the wisdom you gained over the past 50 years, otherwise please go away!
I think QF limiting your speed is a bit cute. We are often asked to maintain 320 to 20 miles and as long as they get us down it is generally okay. In a heavy 800 with winglets it can get exciting if they keep us high but that is rare.
I think QF limiting your speed is a bit cute. We are often asked to maintain 320 to 20 miles and as long as they get us down it is generally okay. In a heavy 800 with winglets it can get exciting if they keep us high but that is rare.
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Yeah SB, they used to trust us in QF to be able to manage that situation as well... then a couple of lowest common denominators spoiled all that.
It will happen with VB too as some stage... just wonder what the response of your management will be.
I get sick of Fly-By-FAM (Flight Admin Manual)
It will happen with VB too as some stage... just wonder what the response of your management will be.
I get sick of Fly-By-FAM (Flight Admin Manual)
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I'm sure the VB drivers are doing what their company tells them to do. The issue is, do the company honchos believe that you can't save fuel at lower flight levels into a headwind.
Under circumstances where you can gain a substantial increase in ground speed your time in the air is much less. You save fuel even though the fuel flow is higher. This ain't rocket science. They'e been doing it since jet airliners were invented. The original TAA B727 drivers who were ex WW2 were doing it in Australia in the 60's and believe me it worked.
However its VB's toy set and they will operate it how they see fit.
As time goes on someone always thinks they've re invented the wheel.
Under circumstances where you can gain a substantial increase in ground speed your time in the air is much less. You save fuel even though the fuel flow is higher. This ain't rocket science. They'e been doing it since jet airliners were invented. The original TAA B727 drivers who were ex WW2 were doing it in Australia in the 60's and believe me it worked.
However its VB's toy set and they will operate it how they see fit.
As time goes on someone always thinks they've re invented the wheel.
I spoke with my "consultant" about the responses above and he confirms that what DJ do is correct in wind conditions where there isn't a huge gradient.
Where the huge gradient exists it is sometimes better to go down, but as the flight plan is calculated on a fixed cost index, the lower you go the slower you go, negating the benefits to a certain extent.
The fix is to run variable cost index plans, and this apparantly is in the works, but there is some re-arranging of the deck chairs and that may take some time to organise because of technical issues with the flight planning computer
In strong winds , particularly with big gradients, it is better to go low, but because of the high proportion that fuel makes up of the total operating cost of the VB fleet, it isn't always obvious which is economically better - the fuel makes up a far larger proportion of the variable operating cost of the aeroplane than most people realise.
Because of this it was decided to have a policy of flying the plan as indicated and accept that on some occasions you are on the losing side of the cost equation - swings and round abouts my contact tells me.
3 bars, using your example of 8-9 minutes for say 200 - 300 kg, under the VB system it would probably be better to stay high, because the cost of that 200 - 300 kg is supposedly more than the cost of the aeroplane maintenance.
This of course completely disregards schedule integrity and other commercial issues.
Amos - thanks for you constructive remarks - I reckon I have got a pretty good grip on how things work.
Borg thanks for the info - the big difference between the two organisations will be the financing of the aeroplanes - that will alter the importance of the cost of fuel in the grand scheme of things
As for ATC putting VB first - I think that if you spoke with QF drivers that would say that VB get preference all the time, if you spoke with VB drivers they would say QF got preference all the time - it is all perception I guess!
Where the huge gradient exists it is sometimes better to go down, but as the flight plan is calculated on a fixed cost index, the lower you go the slower you go, negating the benefits to a certain extent.
The fix is to run variable cost index plans, and this apparantly is in the works, but there is some re-arranging of the deck chairs and that may take some time to organise because of technical issues with the flight planning computer
In strong winds , particularly with big gradients, it is better to go low, but because of the high proportion that fuel makes up of the total operating cost of the VB fleet, it isn't always obvious which is economically better - the fuel makes up a far larger proportion of the variable operating cost of the aeroplane than most people realise.
Because of this it was decided to have a policy of flying the plan as indicated and accept that on some occasions you are on the losing side of the cost equation - swings and round abouts my contact tells me.
3 bars, using your example of 8-9 minutes for say 200 - 300 kg, under the VB system it would probably be better to stay high, because the cost of that 200 - 300 kg is supposedly more than the cost of the aeroplane maintenance.
This of course completely disregards schedule integrity and other commercial issues.
Amos - thanks for you constructive remarks - I reckon I have got a pretty good grip on how things work.
Borg thanks for the info - the big difference between the two organisations will be the financing of the aeroplanes - that will alter the importance of the cost of fuel in the grand scheme of things
As for ATC putting VB first - I think that if you spoke with QF drivers that would say that VB get preference all the time, if you spoke with VB drivers they would say QF got preference all the time - it is all perception I guess!
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Her's a thought .... They probably fly high despite unfavourable conditions because the bloke in the left seats probably got one year on 737 and the f/o's probably got 1000hrs total - and they're just sooo excited. (sorry to the ex dispute guys, they are different, but in the minority by far.)
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Ok! Kiddies, now listen up! (especially our junior flyers SB and VBC)...we will do some basic (PPL) Flight Planning.
Q1. If there is a strong headwind up high and a light wind down low should a pilot fly his aeroplane...
(a) Inverted.
(b) Backwards.
(c) At the lower level.
Now I know this sounds like a trick question, but think about it!
Next week we shall study some basic (PPL) Aerodynamics, such as...
If a pilot wants his aeroplane to go up, should he...
(1) Push the stick down.
(2) Push the stick sideways.
(3) Pull the stick back.
Always remember the basic rules...
(1) RTFQ.
(2) Your first answer is probably the right answer.
The following week we shall move onto advanced (CPL) Aerodynamics and explain how a pilot can make his aeroplane go down! This will be exciting, believe me!
Q1. If there is a strong headwind up high and a light wind down low should a pilot fly his aeroplane...
(a) Inverted.
(b) Backwards.
(c) At the lower level.
Now I know this sounds like a trick question, but think about it!
Next week we shall study some basic (PPL) Aerodynamics, such as...
If a pilot wants his aeroplane to go up, should he...
(1) Push the stick down.
(2) Push the stick sideways.
(3) Pull the stick back.
Always remember the basic rules...
(1) RTFQ.
(2) Your first answer is probably the right answer.
The following week we shall move onto advanced (CPL) Aerodynamics and explain how a pilot can make his aeroplane go down! This will be exciting, believe me!
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I feel that the VB aeroplanes belong to VB and they should be flown as VB request.
The QF aeroplanes belong to QF and they should be flown as QF request.
Why bother with the discussion - boys!
The QF aeroplanes belong to QF and they should be flown as QF request.
Why bother with the discussion - boys!
Ok Amos - here is one for you
If the company tells me to fly the aeroplane in accordance with the flight plan because it is normally more efficient I would:
(a) Fly the aeroplane in accordance with the published company procedures
(b) Fly the aeroplane the contrary to the flight plan because I know better
(c) Don't know because I don't actually fly aeroplanes, I just like making myself feel better by making ******** comments
If the company tells me to fly the aeroplane in accordance with the flight plan because it is normally more efficient I would:
(a) Fly the aeroplane in accordance with the published company procedures
(b) Fly the aeroplane the contrary to the flight plan because I know better
(c) Don't know because I don't actually fly aeroplanes, I just like making myself feel better by making ******** comments
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I think you've just summed yourself up there Dehavillanddriver. That question you have asked and the answer you truly believe to be correct is quite astonishing.
You sound like an absolute clueball.
Perhaps you should have a look at your Performance Manual, thats that bunch of paper wrapped in plastic inside a plastic folder, use pen to break the plastic so you can read it.
Have a look at the difference in fuel burns at different levels.
Also, have you heard of break even wind trade?
Perhaps you should have a read of that if common sense doesn't prevail.
Of course we know better, its called airmanship vs. a flight planner and a computer program, you know, like carrying a TEMPO to a destination when arriving 2 minutes before the TEMPO period.
You aren't flying a sim, though I wish you were with a knowledge base and 'follow the flightplan' attitude like that.
Oh yeah, and next time you depart in front of another aeroplane, try using some airmanship and don't climb at 270kts because you lot are about the only airline in the world who operate so friggin stupidly.
You sound like an absolute clueball.
White aeroplanes steaming past at a great rate of knots, and the fuel burn must be horrendous
Have a look at the difference in fuel burns at different levels.
Also, have you heard of break even wind trade?
Perhaps you should have a read of that if common sense doesn't prevail.
C) Fly the aeroplane the contrary to the flight plan because I know better
You aren't flying a sim, though I wish you were with a knowledge base and 'follow the flightplan' attitude like that.
Oh yeah, and next time you depart in front of another aeroplane, try using some airmanship and don't climb at 270kts because you lot are about the only airline in the world who operate so friggin stupidly.
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Geez!
You Q@NT@S guys are so sensitive.
Taking a lot of things personally aren't we ?
Of course you guys are the best. You have had so much sunshine blown up your collective @rses that you now believe that you are the only blokes who know how to fly. You even know better than Boeing how your machines should be flown !!!
Now can the rest of us who genuinely want to discuss this topic objectively please get on with it.
Thankyou.
You Q@NT@S guys are so sensitive.
Taking a lot of things personally aren't we ?
Of course you guys are the best. You have had so much sunshine blown up your collective @rses that you now believe that you are the only blokes who know how to fly. You even know better than Boeing how your machines should be flown !!!
Now can the rest of us who genuinely want to discuss this topic objectively please get on with it.
Thankyou.