Your best fuel/cost savings tips
Switching to NEO engines saves 15%, or in your example 4500#. Even saving 1% in an industry that regularly has 2% margins can make a difference.
Join Date: May 2009
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You could save a bit of fuel and a lot of localised pollution if you used towbots to take aircraft from the gate and towed them almost to the hold point so that they minimised taxiing and waiting about with the engines running. Nice autonomous towbots ensuring you only have three minutes from startup to takeoff. Heahrow would love it!
SeaTac airport makes a big deal of having pre-conditioned air and ground power available at every gate so there is no need to run the APU at the gate until you're ready to start engines.
Join Date: Jan 2000
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This is the reason why, when all actual winds are used at waypoints, the ABEAM functions in FMC on NG exists, so not to loose valuable data in case of direct clearance...
An operator entering AVG WIND at first waypoint after TOC does so for preflight planning and estimate of time and fuel on arrival in comparison to flight plan, not for inflight use.
Same operator requiring TOC WIND to be entered (wind after ~20 minutes would be good) does so for optimising fuel burn up to TOC, not for estimate time and fuel on arrival.
Therefore not applying both above upsets the preflight prediction on longer flights with multiple wind changes, giving inaccurate data for crew to work with, showing incorrect times and fuel prior to flight.
If FMC is left unchanged and no actual winds for each waypoint are entered (which could be done when time permitting preflight or in cruise flight), when executing a direct clearance, last known wind (AVG or TOC in prior example) is used to predict from next waypoint and onward estimates, however actual wind at time of execution is used for prediction to next waypoint.
When getting cleared for a direct clearance of an hour, where FMC entered TWC at TOC was ~100kts, but wind at execution of direct is HWC ~100kts a ~40% groundspeed differential is observed in estimate for next waypoint, this equates to ~25 minutes.
On similar narrow body you can save up to 50-70kg if you land using idle reverse thrust which can sometimes only be achieved by wasting those 15kgs saved through use of lower flaps. (Slow it down +15kgs, ability for landing with idle reverse -70kgs, saving 55kgs!)
Superpilot nailed it.
I suspect I know what tree he’s barking up.
If you are 30 miles to run, flap 2, 180 knots 3000’ with the chicken stick out then you are wasting more fuel than the savings just listed above save.
Seen it too many times in my career, so many pilots totally clueless about altitude versus track miles.
I suspect I know what tree he’s barking up.
If you are 30 miles to run, flap 2, 180 knots 3000’ with the chicken stick out then you are wasting more fuel than the savings just listed above save.
Seen it too many times in my career, so many pilots totally clueless about altitude versus track miles.
Join Date: Aug 2013
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Oh wait...that’s probably how they get their 15% savings..
Join Date: Apr 2008
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Agree. also a good one is if you've gone for high speed but get an intermediate level off FFS SLOW DOWN. Keeping the higher speed at low or mid altitudes haemorages fuel like nothing else. Not that ATC gives a hoot....
Readily available Ground Power and Air is not very common at our US destination. Lots of prolonged APU use. Good on SEA!
Join Date: Oct 2010
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Any one knows what the difference in full consumption is if you modify the descent speed from CI (around 270kias) to say 300 on a medium size aircraft? You'll keep cruise power a few minutes longer but your descent will be shorter, taking advantage of the higher GS/TAS.
I've done this to save a couple of minutes when going behind schedule but don't know how does it affect fuel economy (haven't done the fuel gauges vs computer flight plan math to be honest).
I've done this to save a couple of minutes when going behind schedule but don't know how does it affect fuel economy (haven't done the fuel gauges vs computer flight plan math to be honest).
Join Date: Jan 2000
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Any one knows what the difference in full consumption is if you modify the descent speed from CI (around 270kias) to say 300 on a medium size aircraft? You'll keep cruise power a few minutes longer but your descent will be shorter, taking advantage of the higher GS/TAS.
I've done this to save a couple of minutes when going behind schedule but don't know how does it affect fuel economy (haven't done the fuel gauges vs computer flight plan math to be honest).
I've done this to save a couple of minutes when going behind schedule but don't know how does it affect fuel economy (haven't done the fuel gauges vs computer flight plan math to be honest).
Work out time spent extra in cruise (check against calculated TOD to get minutes extra) then based on above work out additional cruise fuel requirement;
Work out the fuel flow for your aircraft type in descent (~500 kr/hour for 737);
Work out time spent less in descent (use RTA for runway prior and after KIAS increase (earlier arrival therefore time gained, then reduce it by additional time spent in cruise), this gives descent saving;
You WILL find out that a minute extra in fuel in cruise (~40 kg) can only be regained by reducing descent time by >6 minutes which means this was it is to generate a fuel saving.
Starting an idle descent as soon as possible at best glide speed (lowest CI) is most fuel efficient.
Drain Bamaged
Join Date: Oct 2010
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Thanks Skyjob, that's quite helpful. Should be interesting to run the math even if you already gave out the answer haha
@ehwhatezedoing
Forget a runway overrun. That's taking it to the extreme. Depending on runway length, current conditions and aircraft weight, you would need to reduce flex to a lower degree to meet perform requirements plus the increase in fuel associated with the increase in power. Unless really light on weight (i.e. no reduction in flex for takeoff) I don't think it would save too much.
P.S. We aren't allowed to do intersection takeoffs at our gig
@ehwhatezedoing
Forget a runway overrun. That's taking it to the extreme. Depending on runway length, current conditions and aircraft weight, you would need to reduce flex to a lower degree to meet perform requirements plus the increase in fuel associated with the increase in power. Unless really light on weight (i.e. no reduction in flex for takeoff) I don't think it would save too much.
P.S. We aren't allowed to do intersection takeoffs at our gig
Join Date: Jul 2014
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Just put a spare engine in the cargo compartment.
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however, cost in terms of engine life are significant so most stick with derate/flex for commercial reasons. unless you have an engine maintainance contract that doesnt mention flex/drt vs Max, in which case, let er rip!!!
Fuel critical sector, max rated TO provides lowest burn.
however, cost in terms of engine life are significant so most stick with derate/flex for commercial reasons. unless you have an engine maintainance contract that doesnt mention flex/drt vs Max, in which case, let er rip!!!
however, cost in terms of engine life are significant so most stick with derate/flex for commercial reasons. unless you have an engine maintainance contract that doesnt mention flex/drt vs Max, in which case, let er rip!!!
Come to find out, they were using max TO every single takeoff - never a derate of any kind. At around a million dollars to overhaul an engine, you'd have to save a whole lot of of fuel to justify an extra two million dollars/year in engine maintenance...