How to burn 18.4% less fuel and live. Really.

Courtesy of Oxford Aviation Academy and SAS at OAA’s Stockholm base, I have just flown an A320 twice from Gothenburg to Copenhagen, with identical weights in identical conditions both times.

But, by adopting a few modified procedures the second time, we used 18.4% less fuel.

Don’t try all these tricks on your next trip without having a word with your ops and training standards people, because even SAS, which has been working for a few years with OAA to develop “Eco-Piloting” techniques and training, has only just got there, and has not yet begun the process of transferring the new tricks onto the line.

If you want to learn about the techniques SAS/OAA have been trialling, register for Flight International’s Pilot Best Practice/Crew Management Conference in London at the end of this month and you can talk to Per de la Motte, OAA’s Director of Training, Nordic region about his secrets.

Back to my two short trips.

Given that, on the first trip, my mentor in the right hand seat, OAA’s fuel-efficiency guru Peter Fogtmann, ensured that we used normal SAS/A320 SOPs and standard routeing with absolutely no shilly-shallying, I wouldn’t have thought a fuel saving of 18.4% was possible. But its what we did. Since it’s only a 25min hop, 18.4% translates as a 320kg fuel saving, which may not sound much - but what a percentage! Save that every trip for a year and you’re talking big bucks and dramatically reduced emissions.

Of course Peter and I are in a simulator, but it’s a Level D FFS, so the figures we get should represent the truth, as near as dammit.

The first trip was done the way any good line pilot would do it, so I won’t bore you with that. But here are the differences applied on the second trip:

  • Reduced the cost index from 30 to 7 in the FMS;
  • Chose Malmo instead of Gothenburg as the alternate, which meant we could carry 450kg less fuel;
  • APU was started only moments before pushback;
  • Single-engine taxi (using No 1 engine). APU was shut down once No 1 was established and checked;
  • No 2 was started with 3min to go to line-up for take-off;
  • Take-off was carried out with flap/slat 1 instead of 2, and packs off;
  • Power levers retarded to “climb” detent at 800ft (instead of 1,500-3,000ft), and acceleration initiated at that point;
  • Request for optimum speed below 10,000ft accepted, and continued at 305kt (opt) instead of sticking to standard 250kt;
  • Request direct routeing at every opportunity (in this case the routeing was almost direct anyway, so there were no benefits there);
  • Input forecast or actual winds rather than standard seasonal;
  • Initiate descent at a carefully estimated point beyond normal TOD because continuous descent approach was likely to be available;
  • Flap 1 selected at glideslope intercept; flap 2 at 2,000ft; gear down just before 1,000ft; flap 3 selected just before 500ft (would be 1,000ft in IMC); land with flap 3 instead of 4;
  • Idle reverse during landing run;
  • 3min after touchdown, No 2 engine shut down; single-engine taxi to stand.

Yes I know you wouldn’t be able to do all those things on many regular trips, and hardly any of them in busy terminal areas during the winter, but just doing some of them when you can provides a benefit that makes a difference. Yes I know you have to consider icing procedures in unkind weather, but sometimes the sun shines.

SAS and OAA, who are making this kind of expertise a speciality, say it’s about a mindset. A mindset that hasn’t been examined critically for a long time, with the result that there are lots of treasured beliefs out there that are effectively urban myths.

Come and listen to Per, and find out what he has found out.

 

13 Responses to How to burn 18.4% less fuel and live. Really.

  1. Blu Yonder 6 November, 2009 at 12:32 am #

    How irresponsible! I cannot even start thinking what bad practices this article is advocating! Let me start point by point!
    1. Reducing CI from 30 to 7, you should have gone ahead and set it to 0, which is the actual minimum fuel CI for the A320. You can save time by using CI 25 (kg/hr) which is LRC.
    2. Choosing the shortest alternate. Did you check if the proper procedure was setup in the flight plan and the longest STAR used? You would be pretty dumb turning up at your alternate with less than minimum legal fuel.
    3. good, but one has to consider extreme temperatures, we carry live passengers something a Level D sim does not simulate very accurately!
    4.Single engine taxi with APU off. What happens if you loose that engine or EDP? left with only ACCU pressure to power your brakes and no NWS in some aircraft! Leave that APU on as it your only backup!
    5. Start no. 2 engine 3 minutes before T/O. CFM arecommends at least 5 mins taxi to reduce EGT thus engine wear. What you are doing is only increasing an eventual engine wear which ultimately increases fuel consumption throughout the airframe life.
    6. Use flaps1. Very good idea in places like Scandinavia and on shorter rwys. One setting does not fit all circumstances. Flaps 2 is rarely optimum conf BTW.
    7. Power reduction and flap retraction is stipulated by ICAO NADP 1 2 or 3
    8. I find 305 KIAS relatively high for such a CI, but it depends on what cruise altitude you have input and what weight you are flying. 250 KIAS is there mostly for ATC traffic separation
    9 and 10 is what most pilots strive to do.
    11. Overshoot T/D i would not recommend as it gives an approximate 2.9 degree descent and caters for re pressurisation schedules and other considerations like engine anti ice. V/S mode is recommended below 6000ft for CDAs
    12. a. Flaps one selected at G/S intercept will, with certain weights and winds not slow the plan down to below VFE Flaps 2.
    b. Flaps 2 at 2000ft is a MINIMUM recommended by Airbus. At this point you are still at around 190-180KIAS with flaps straining. (they are not speedbrakes you know)
    c. Gear down at 1000ft. Still doing around 160-170 KIAS ( stabilised approach criteria busted, G/A HIGHLY recommended)
    d. Flap 3 at just before 500ft, Did you land in IDLE? probably spool up at around 100ft. VERY dangerous practice.
    e. Flap 3 is recommended by Airbus for windshear conditions and some failure modes. Requires O/H panel switching and MCDU inputs and approx 5 KIAS higher landing speed.
    13 and 14 are recommended for engine, brake wear, noise and Fuel, but start that APU!
    We routinely save 500-600kg of fuel from flightplan on a particular 25 minute flight!
    Also doing a packs off T/O saves fuel and engine wear whilst having more available power if you get that sinking feeling.
    I hope that the points are reconsidered, too many pilots approaching high and fast, forgetting to start descent and continuing beyond destination, forgetting landing gear, botched G/A procedures. Let us not loose the big picture with this fuel consumption issue.

    Be safe.

  2. Thomas Fernandez 6 November, 2009 at 1:27 am #

    To be honest a number of LCC A320 operators in the SE Asia practise most of the mentioned techniques.

    for eg:

    1. Use of CI as 10. (the full service 320 oeprators use 27 or 26)
    2. One Engine taxi out.
    3. Packs off take off.
    4. Thrust levers to CLB detent still is done only at Accl altitude ie, 1500 ft AGL
    5. Requests for opt climb speed mostly get rejected by ATC due to heavy traffic on the SIDs and trunk routes. However it usually gets approved from remote stations where traffic is virtually NIL :)
    5. Flaps 1 selected at glideslope intercept; flaps 2 at 2,000ft followed by Gear down and flaps 3 BEFORE 1000 ft for IMC conditions.
    6. Landings on Flaps 3 only.
    7. Idle reverse during landing run. Use of reversers allowed only for safety reasosn and ofcourse for the remote stations that have a 30×1500 m runway!
    8. Single engine taxi to stand is being thought about now. dont know when it will be enforced though!

    The bottom line is that all of the above cannot be done in a single flight. Flights usually origintae from a primary city going to a remote destination with a challenging runway. Hence usually some of the above techniques can be implemented. at the end of the day people are getting more and more innovative on as to how to save fuel! Question is …how much more can be achived without compromising saftey?

  3. David Learmount 6 November, 2009 at 10:19 am #

    Thanks Blu Yonder – lots of valid points. Like I said, these ideas are not line-ready yet, but they should all be tested, and debated, like this.

    Just to answer your curiousity about whether we landed in idle, speeds from G/S intercept onward were good, and we were still at idle at that point. Power came up just as we passed 500ft. So, from the fuel economy point of view that may have been perfect, but it did make me nervous. Peter (my RHS skipper) says that power by 500ft is essential to ensure credible go-around capability, let alone icing or other concerns.

    But it doesn’t leave anything “for the wife and kids”, which culturally is something we are accustomed to. Should we challenge our old beliefs? Let’s hear more.

  4. 121 Pilot 12 November, 2009 at 1:07 pm #

    A bit of background. I’m a pilot for a US Major LCC which operates a large fleet of A320′s which is the aircraft I’m currently assigned to.

    1.)We use a CI of 35. The company has experimented with using different numbers but found that the fuel savings was lost because of the ATC issues the slower than normal speeds in the decent created.
    2.)Smart Alternate selection is important. The key as always is staying ahead of the situation and having a workable backup plan should your close in alternate not workout.
    3.)The A320 has one of the slowest starting APU’s I’ve ever seen. The best technique I’ve found is to get the APU door open as departure time nears and commence the start sequence when the agent comes up to the cockpit to close out the flight. Not mentioned in this is what we call a “smart start” Where start of the first engine is delayed until the pushback is nearly complete to ensure that your not sitting there with the engine running and ready to go while they are disconnecting the tug. Done properly the tug is pulling away as the engine stabilizes reducing running time.
    4.)Single engine taxi is SOP but I’m not sure about shutting the APU down. I don’t see a serious safety issue but on many flights because of the start up and shut down times you really can’t gain much if anything. Now on a long taxi out this sounds an excellent idea. I disagree with blu yonder that a failure of the number one engine on taxi without the APU is going to be a serious safety issue. Your tax speed should always be such that the accum will provide plenty of braking power to get the aircraft stopped.
    5.) The 5 min time period referenced by blu yonder is for an engine that has been shut down for more than 2 hours. Under that time period the required warmup is only 2 minutes. At least on our V2500 equipped fleet. The GE engines may be different
    6.) Flaps 1 is SOP for us unless performance requirements dictate otherwise (BUR is Flaps 3 for example) but I don’t like the packs off idea. To my way of thinking the fuel savings (and I’d be interested to know just how much this one item saves) isn’t worth the passenger comfort issues this creates.
    7.) Acceleration altitude (aka power to CLIMB) is normally 1000 AFE for us.
    8.) Greater than 250kts below 10,000 isn’t possible in the US due to the FAR’s and does create a whole new string of hazards. Bird strikes become much more serious and traffic avoidance with light aircraft is far more problematic. Their was an experiment in the US with using higher speeds below 10,000 but it was ultimately rejected.
    9+10.) Direct routing and actual winds. Important but you must be aware that on some flights (aka Winter Transcons) you are better off on the flight planned routing than taking the shortcut and going direct.
    11.) If you have properly loaded the winds and set up the FMS then the computed TOD point will almost always generate an Idle power descent all the way down. I’ve seen this going into SJU at night for example where we can have the flight plan connected to the ILS and the result is idle power all the way from cruise to when the aircraft stabilizes on the approach. If only this was available all the time!
    12.) The key thing here is proper speed management. In VFR stabilized by 500′ (on speed and engines spooled) is acceptable in IFR you need 1000′ The exact altitudes you select flaps 1 etc. will vary with weight, winds etc.
    13+ 14.)Idle reverse and single engine taxi in are SOP for us as well. We’ve been taxing in on one engine with no APU for years and have never had an issue because of it.

    As you can see much of this is already being applied at a great many carriers. The key is often to get your employees to fully embrace the practices you want them to use and not carry all the “extras for the kids”.

  5. Blu Yonder 16 November, 2009 at 5:41 pm #

    121 pilot, running on one engine without APU and having an engine failure will leave you with no electrics accept battery power below 50 KTS criteria and ACCU pressure. Also On FCOMs VOL 3 section 90, Airbus clearly states to start APU both for departure and arrival.It also states 3 minutes before start and shut down. “TECHNICAL AMENDMENT 1)Page created to indicate that the last engine must be started no less than 3 minutes before takeoff, to ensure that : -The engine operates at idle or near idle for at least 2 minutes before pushing the thrust lever forward to high power. This is to avoid engine thermal shock. -The engine runs for at least ADDITIONAL INFORMATION 2 minutes before takeoff initiation, so that takeoff is not initiated before the center tank pumps test is finished, since takeoff on center tank is prohibited.”
    Packs off takeoff has no effect on passenger comfort except at extreme temperatures. CI of 35 is LRC in Lbs/hr. Metric we use 25 Kgs/hr.
    I am all for fuel saving but not for the sake of saving fuel and loosing the bigger picture, i.e. safety. Going against OEM recommendations is also a serious issue.

    regards

  6. 121 Pilot 17 November, 2009 at 4:30 am #

    Blu Yonder,

    I’m afraid I don’tr have a Volume 3 of the FCOM as we only use Volume 1 & 2 both of which are specific to my carrier and both of which have been approved by both the FAA and Airbus.

    Yes running one engine and no APU means that if the engine failes you lose everything except battery power and the pressure in the accumulator. In the 10+ years my carries has flown the A320 we’ve never had an issue that resulted from single engine taxi with the APU shutdown which is SOP for taxi in. I maintain that if you keep your taxi speed reasonable the loss of elec and hyd power does not endanger the airplane since the accummulator will have plenty of power to effect a stop and set the parking brake.

    As for engine start the 2 minutes I referenced starts after you have a stabilized start which means a little over 3 minutes from start initiation. We are saying the same thing just using different markers.

    A packs off takeoff does affect pax comfort because you have no pressurization which means the rate of climb in the cabin will be much greater until the packs are on and you’ll probably get a bump when you do so. Then add in the loss of conditioned air you already mentioned.

    As you can see nothing that we do is contrary to an Airbus approved procedure. One must remember that many airlines have airline specific manuals which often have procedural variances from those found in the basic manuals and which have been approved by the manufacturer.

  7. Noel Falconer 17 November, 2009 at 8:42 am #

    Point-to-point, altitude-optimised flight is feasible and promises major savings, we even know pretty well how to mass-implement it.

    What it isn’t is proven safe. We might test the water by adding ptpao flights to the present system, progressively, initially theoretically, and always with collision-avoidance equipped aircraft, while observing conflicts; this is less than optimal but looks practicable, which a jump-switch isn’t.

  8. Blu Yonder 17 November, 2009 at 5:31 pm #

    121 pilot,
    Aviation has this level of safety because of redundancy so if your airline goes that way, good luck for you but at the moment our paradigm shift is towards having slightly larger margins for safety’s sake. We never had engine failures, knock on wood, on our Airbus fleet in over 18 years but we still consider 85kg/hr APU fuel burn during taxying worth it and we go on Airbus recommendations too.
    Regarding Packs OFF takeoff, trust me, it is unnoticeable from a pressurisation point of view especially with TRA of 1000ft AAL. It saves on engine wear and therefore fuel consumption throughout the engine lifetime. It is not procedure either in our airline but recommended on short field ops.
    What about upload of AZFW before deciding Block Fuel and upload of latest winds via ACARS for the flight? That is something which gives you more fine tuning for Optimum FL and updated CI also according to airline exigencies.
    Happy Landings

  9. MadDog Eleven 17 November, 2009 at 6:02 pm #

    What it all boils down to is to keep your common sense guys and girls, and fly the aircraft and not the paper-airplanes coming out of offices. I’ve seen fellow pilots do stupid things just to keep their fuel-savings looking nice for management.
    A lot of the points mentioned by Learmount are being applied in varying ways in different operations. Any small saving will accumulate over time and thus be significant. But lets not forget the old saying – penny wise pound foolish.

  10. Danusa 22 November, 2009 at 5:32 pm #

    Which GE engine for 320′s? Ho ho! You mean CFM, 50/50 with Safran? Thx,

  11. Davies 16 December, 2009 at 4:10 pm #

    Debate yes!

    But do not let it get into the hands of the bean counters!

  12. Miranda Robinson 1 January, 2010 at 9:07 pm #

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  13. Florence Farid 13 March, 2010 at 11:58 pm #

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