航空论坛 发表于 2011-8-15 03:25:07

Fuel Conservation 燃油管理

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航空论坛 发表于 2011-8-15 03:26:09

Fuel Conservation<BR>Flight Operations Engineering<BR>Boeing Commercial Airplanes<BR>November 2004<BR>Fuel Conservation 2<BR>What is Fuel Conservation?<BR>Fuel conservation means managing the<BR>operation and condition of an airplane to<BR>minimize the fuel used on every flight<BR>Fuel Conservation 3<BR>*Assumes typical airplane utilization rates. Actual utilization rates may differ.<BR>How Much Is A 1% Reduction In Fuel Worth?<BR>Airplane Fuel savings*<BR>type gal/year/airplane<BR>777 70,000 → 90,000<BR>767 30,000 → 40,000<BR>757 25,000 → 35,000<BR>747 100,000 → 135,000<BR>737 15,000 → 25,000<BR>727 30,000 → 40,000<BR>Fuel Conservation 4<BR>How Much Is This Worth In $$?<BR>Depends on Current Fuel Prices!<BR>Fuel Conservation 5<BR>Jet Fuel Prices<BR>Source: Air Transport World<BR>Year<BR>$/gallon<BR>$0.00<BR>$0.20<BR>$0.40<BR>$0.60<BR>$0.80<BR>$1.00<BR>$1.20<BR>$1.40<BR>87 89 91 93 95 97 99 01 03<BR>$1.00<BR>Fuel Conservation 6<BR>Airplane Fuel savings* Fuel savings*<BR>type gal/year/airplane $/year/airplane<BR>*Assumes $1.00/gallon<BR>How Much Is A 1% Reduction In Fuel Worth?<BR>777 70,000 → 90,000 $70,000 → 90,000<BR>767 30,000 → 40,000 $30,000 → 40,000<BR>757 25,000 → 35,000 $25,000 → 35,000<BR>747 100,000 → 135,000 $100,000 → 135,000<BR>737 15,000 → 25,000 $15,000 → 25,000<BR>727 30,000 → 40,000 $30,000 → 40,000<BR>*Assumes typical airplane utilization rates. Actual utilization rates may differ.<BR>Fuel Conservation 7<BR>What Is Fuel Conservation<BR>From An Airline Business Viewpoint ?<BR>Fuel conservation means managing the<BR>operation and condition of an airplane to<BR>minimize the fuel used on every flight<BR>total cost of<BR>Fuel Conservation 8<BR>Total savings =<BR>fuel savings<BR>- cost to<BR>implement<BR>Cost to Total Cost<BR>Implement Savings/AP<BR>?? ??<BR>Airplane Fuel savings* Fuel savings*<BR>type gal/year/airplane $/year/airplane<BR>How Much Is A 1% Reduction In Fuel Worth?<BR>777 70,000 → 90,000 $70,000 → 90,000<BR>767 30,000 → 40,000 $30,000 → 40,000<BR>757 25,000 → 35,000 $25,000 → 35,000<BR>747 100,000 → 135,000 $100,000 → 135,000<BR>737 15,000 → 25,000 $15,000 → 25,000<BR>727 30,000 → 40,000 $30,000 → 40,000<BR>*Assumes $1.00/gallon<BR>*Assumes typical airplane utilization rates. Actual utilization rates may differ.<BR>Fuel Conservation 9<BR>Saving Fuel Requires Everyone’s Help<BR>• Flight Operations<BR>• Dispatchers<BR>• Flight Crews<BR>• Maintenance<BR>• Management<BR>10<BR>FLIGHT<BR>OPERATIONS<BR>ENGINEERING<BR>Operational Practices<BR>for Fuel Conservation<BR>Fuel Conservation 11<BR>Flight Operations / Dispatchers<BR>• Landing weight<BR>• Fuel reserves<BR>• Airplane loading<BR>• Flap selection<BR>• Altitude selection<BR>• Speed selection<BR>• Route selection<BR>• Fuel tankering<BR>Opportunities For Fuel Conservation<BR>Fuel Conservation 12<BR>Reduced Landing Weight<BR>1% reduction in landing weight produces:<BR>≅ 0.75% reduction in trip fuel (high BPR engines)<BR>≅ 1% reduction in trip fuel (low BPR engines)<BR>Fuel Conservation 13<BR>Required Additional<BR>WLDG = OEW + Payload + reserve + fuel loaded<BR>fuel but not used<BR>Zero fuel weight<BR>Fuel on board at landing<BR>Components Of Landing Weight<BR>Fuel Conservation 14<BR>Approximate % Block Fuel Savings Per<BR>1000 Lb (454 Kg) ZFW Reduction<BR>737-<BR>3/4/500<BR>737-<BR>6/7/8/900<BR>757-<BR>200/300<BR>767-<BR>2/3/400<BR>777-<BR>200/300 747-400<BR>.7% .6% .5% .3% .2% .2%<BR>717-200<BR>.9%<BR>Reducing ZFW Reduces Landing Weight<BR>Fuel Conservation 15<BR>Reducing OEW Reduces Landing Weight<BR>• Passenger service items<BR>• Passenger entertainment items<BR>• Empty Cargo and baggage containers<BR>• Unneeded Emergency equipment<BR>• Excess Potable water<BR>Items To Consider<BR>Fuel Conservation 16<BR>Reducing Unnecessary Fuel<BR>Reduces Landing Weight<BR>• Practice cruise performance monitoring<BR>• Flight plan by tail numbers<BR>Fuel Conservation 17<BR>Fuel Reserves<BR>• Carry the appropriate amount of reserves to ensure<BR>a safe flight and to meet your regulatory requirements<BR>• Extra reserves are extra weight<BR>• Airplane burns extra fuel to carry the extra weight<BR>Fuel Conservation 18<BR>Fuel Reserves<BR>The amount of required fuel reserves depends on:<BR>• Regulatory requirements<BR>• Choice of alternate airport<BR>• Use of re-dispatch<BR>• Company policies on reserves<BR>• Discretionary fuel<BR>Fuel Conservation 19<BR>Regulatory Requirements<BR>• Is this an international flight?<BR>• FAA rules?<BR>• ICAO rules?<BR>• Other rules?<BR>Fuel Conservation 20<BR>FAA “International Reserves”<BR>(A) To fly to and land at the airport to which it is released;<BR>(B) After that, to fly for a period of 10 percent of the total time required to fly from the<BR>airport of departure to, and land at, the airport to which it was released;<BR>(C) After that, to fly to and land at the most distant alternate airport specified in the<BR>flight release, if an alternate is required; and<BR>(D) After that, to fly for 30 minutes at holding speed at 1,500 feet above the alternate<BR>airport (or the destination airport if no alternate is required) under standard<BR>temperature conditions.<BR>FAR 121.645(b)<BR>D<BR>C<BR>B<BR>A<BR>Conttiingency<BR>Alltterrnatte<BR>Holldiing<BR>Fuel Conservation 21<BR>FAA “Island Reserves”<BR>• No alternate is specified in release under Section<BR>121.621(a)(2) or Section 121.623(b).<BR>• Must have enough fuel, considering wind and other<BR>weather conditions expected, to fly to destination<BR>airport and thereafter to fly for 2 hours at normal<BR>cruising fuel consumption<BR>FAR 121.645(c)<BR>Fuel Conservation 22<BR>ICAO International<BR>4.3.6.3.1 When an alternate aerodrome is required;<BR>To fly to and execute an approach, and a missed approach,<BR>at the aerodrome to which the flight is planned, and<BR>thereafter:<BR>A) To fly to the alternate aerodrome specified in the<BR>flight plan; and then<BR>B) To fly for 30 minutes at holding speed at 450 M<BR>(1,500 ft) above the alternate aerodrome under standard<BR>temperature conditions, and approach and land; and<BR>C) To have an additional amount of fuel sufficient to<BR>provide for the increased consumption on the occurrence<BR>of any of the potential contingencies specified by the<BR>operator to the satisfaction of the state of the operator<BR>(typically a percentage of the trip fuel: 3% to 6%).<BR>C<BR>A<BR>B<BR>Conttiingeenccyy<BR>Holldiing<BR>Alltteerrnaattee<BR>ICAO Annex 6 (4.3.6.3)<BR>Fuel Conservation 23<BR>Alternate Airport<BR>What items should you consider when choosing<BR>an alternate airport?<BR>• Airline facilities<BR>• Size and surface of runway<BR>• Weather<BR>• Hours of operation, lighting<BR>• Fire fighting, rescue equipment<BR>Fuel Conservation 24<BR>Alternate Airport<BR>What items should you consider when choosing<BR>an alternate airport?<BR>• Airline facilities<BR>• Size and surface of runway<BR>• Weather<BR>• Hours of operation, lighting<BR>• Fire fighting, rescue equipment<BR>Fuel Conservation 25<BR>Speed Selection for Holding<BR>• Want to maximize time per kilogram of fuel<BR>• Use published/FMC recommended holding<BR>speeds<BR>Fuel Conservation 26<BR>Use Redispatch to Lower Contingency Fuel<BR>• Reserve/contingency fuel is a function of trip<BR>length or trip fuel burn<BR>• Originally implemented to cover errors in<BR>navigation, weather prediction, etc...<BR>• Navigation and weather forecasting techniques<BR>have improved, decreasing the chance that<BR>contingency fuel will actually be used<BR>Fuel Conservation 27<BR>How Redispatch Works<BR>Climb<BR>Descent<BR>Cruise<BR>Intended<BR>destination<BR>Origin<BR>Redispatch<BR>point<BR>Initial<BR>destination<BR>Fuel Conservation 28<BR>Intended<BR>Origin destination<BR>Intended<BR>Origin destination<BR>Redispatch<BR>point<BR>Initial<BR>destination<BR>Redispatch<BR>point<BR>Initial<BR>destination<BR>Off Track Initial Destination<BR>Fuel Conservation 29<BR>Intent is to lower the Contingency Fuel On<BR>Board at the Final Destination<BR>Distance<BR>(Time)<BR>Redispatch<BR>point<BR>Contingency<BR>fuel<BR>Contingency Fuel required<BR>Intended<BR>destination<BR>Contingency<BR>Fuel required<BR>Reduction<BR>Fuel Conservation 30<BR>Reduced fuel load<BR>Increased payload<BR>Benefits of Redispatch<BR>Fuel Conservation 31<BR>B<BR>Initial<BR>destination<BR>A<BR>Origin<BR>C<BR>Final<BR>destination<BR>Examples of Using Redispatch<BR>To: 1) Increase payload<BR>2) Decrease takeoff and landing weight<BR>(by reducing fuel load)<BR>Fuel Conservation 32<BR>Example of payload<BR>increase with constant<BR>takeoff weight<BR>OEW<BR>PAYLOAD<BR>(1)<BR>Altern + Hold<BR>Contingency<BR>TRIP<BR>FUEL<BR>TRIP<BR>FUEL<BR>Same takeoff weight with and<BR>without redispatch<BR>Optimum<BR>redispatch point<BR>A C<BR>OEW<BR>A B<BR>(No redispatch)<BR>PAYLOAD<BR>(2)<BR>Altern + Hold<BR>Contingency<BR>PAYLOAD<BR>(2)<BR>B C<BR>OEW<BR>TRIP FUEL<BR>Altern + Hold<BR>Contingency<BR>Gross<BR>weight<BR>Fuel Conservation 33<BR>Example of takeoff<BR>weight and landing<BR>weight decreases with<BR>constant payload<BR>OEW<BR>PAYLOAD<BR>(1)<BR>Altern + Hold<BR>Contingency<BR>TRIP<BR>FUEL<BR>TRIP<BR>FUEL<BR>Optimum<BR>redispatch point<BR>A C<BR>(No redispatch)<BR>A B B C<BR>OEW<BR>PAYLOAD<BR>(2)<BR>PAYLOAD<BR>(2)<BR>OEW<BR>TRIP FUEL<BR>Altern + Hold<BR>Contingency Contingency<BR>Altern + Hold<BR>Takeoff weight decrease<BR>Landing<BR>weight (1)<BR>Landing weight (2)<BR>(decrease from (1))<BR>Gross<BR>weight<BR>Fuel Conservation 34<BR>WT (fwd c.g.) Lift tail (fwd c.g.)<BR>Lift wing (fwd c.g.)<BR>• At aft c.g. the lift of the tail is less negative than at forward<BR>c.g. due to the smaller moment arm between Liftwing and WT<BR>• Less angle of attack, α, is required to create the lower Liftwing<BR>required to offset the WT plus the less negative Lifttail<BR>• Same Lifttotal, but lower Liftwing and therefore lower α required<BR>Lift wing (aft c.g.)<BR>WT (aft c.g.)<BR>Lift tail (aft c.g.)<BR>&lt;<BR>= Is less negative than<BR>Airplane Loading<BR>Maintain C.G. In The Mid To Aft Range<BR>Fuel Conservation 35<BR>4 8 12 16 20 24 28 32 36<BR>Center of gravity, %MAC<BR>Incremental<BR>cruise drag, %<BR>-2<BR>-1<BR>0<BR>1<BR>2<BR>3<BR>4<BR>5<BR>0.70<BR>0.65<BR>0.60<BR>0.55<BR>0.50<BR>Typical trim drag increment at cruise Mach<BR>Airplane Loading (continued)<BR>Maintain C.G. in the Mid to Aft Range<BR>W/δ (LB *10-6)<BR>Actual variation in<BR>drag due to C.G.<BR>depends on airplane<BR>design, weight,<BR>altitude and Mach<BR>Fuel Conservation 36<BR>Flap Setting<BR>Choose lowest flap setting that will meet takeoff<BR>performance requirements:<BR>• Less drag<BR>• Better climb performance<BR>• Spend less time at low altitudes, burn less fuel<BR>Fuel Conservation 37<BR>Altitude Selection<BR>Pressure altitude for a given weight and speed<BR>schedule that produces the maximum air miles per<BR>unit of fuel<BR>Optimum Altitude Definition<BR>Fuel Conservation 38<BR>Definition of Optimum Altitude<BR>FUEL MILEAGE (NAM/LB)<BR>PRESSURE ALTITUDE (1000 FT)<BR>0.024 0.028 0.032 0.036 0.040 0.044 0.048<BR>30<BR>32<BR>34<BR>36<BR>38<BR>40<BR>GROSS WT<BR>(1000 LB)<BR>620<BR>580<BR>540<BR>500<BR>460 420 380 340<BR>300<BR>OPTIMUM<BR>(CONSTANT MACH<BR>NUMBER)<BR>Pressure Altitude Which Provides the Maximum Fuel<BR>Mileage for a Given Weight and Speed<BR>Fuel Conservation 39<BR>LRC Mach<BR>Determining Optimum Altitude<BR>Cruise weight (1000 KG)<BR>Brake release weight (1000 KG)<BR>45<BR>40<BR>35<BR>30<BR>60 70 80 90 100 110 120<BR>70 80 90 100 100 120<BR>Pressure<BR>altitude<BR>(1000 ft)<BR>Fuel Conservation 40<BR>Step Climb<BR>= Off optimum operations<BR>Optimum<BR>Altitude<BR>4000 ft<BR>2000 ft<BR>Step<BR>climb<BR>Fuel Conservation 41<BR>Optimum altitude<BR>+ 1.5%<BR>+ 1.5%<BR>1000 ft<BR>+ 0.5%<BR>+ 3.0%<BR>+ 0.5%<BR>+ 6.5%<BR>+ 1.5%<BR>+ 8.5%<BR>4-hour Average = + 4.8%<BR>+ 0%<BR>+ 4.5%<BR>4-hour Average = + 0.6%<BR>Off-Optimum Fuel Burn Penalty<BR>4000 ft Step vs. No Step Over a 4-Hour Cruise<BR>(Example Only)<BR>Fuel Conservation 42<BR>Speed Selection<BR>NAM/<BR>pound<BR>fuel<BR>MACH number<BR>0.12<BR>0.11<BR>0.10<BR>0.09<BR>0.08<BR>0.07<BR>0.06<BR>0.60 0.64 0.68 0.72 0.76 0.80 0.84<BR>0.05<BR>Increasing<BR>weight<BR>LRC<BR>MMO<BR>MRC = Maximum range cruise (speed producing maximum fuel mileage for a given weight)<BR>LRC = Long Range cruise (speed which produces a 1% decrease in FM relative to MRC)<BR>1%<BR>LRC Versus MRC<BR>MRC<BR>Fuel Conservation 43<BR>Speed Selection (continued)<BR>• LRC = MRC + 1% fuel burn<BR>• Significant speed increase for only<BR>a 1% decrease in fuel mileage<BR>• Increases speed stability<BR>• Minimizes throttle adjustments<BR>LRC Versus MRC<BR>Fuel Conservation 44<BR>0<BR>1<BR>2<BR>3<BR>4<BR>5<BR>6<BR>7<BR>8<BR>0.00 0.01 0.02 0.03 0.04<BR>Δ Mach from MRC<BR>Δ Fuel ~ %<BR>-30<BR>-25<BR>-20<BR>-15<BR>-10<BR>-5<BR>0<BR>0.00 0.01 0.02 0.03 0.04<BR>Δ Mach from MRC<BR>Δ Time ~ min.<BR>LRC<BR>Model #1<BR>Model #2<BR>Model #2<BR>Model #1<BR>LRC Model #1<BR>LRC Model #2<BR>Δ Fuel For Flying Faster Than MRC<BR>Flying Faster Than MRC?<BR>Flying faster than LRC typically produces a significant fuel<BR>burn increase in return for a relatively small time savings<BR>(example based on 5000 NM cruise)<BR>Δ Time For Flying Faster Than MRC<BR>Actual fuel burn increase, and time decrease, for flying faster than<BR>MRC depends on specific airplane model, weight, and altitude<BR>Fuel Conservation 45<BR>Speed Selection - Other Options<BR>• Cost Index = 0 (maximize ngm/lb<BR>= wind-adjusted MRC)<BR>• Selected Cost Index (minimize costs)<BR>• Maximum Endurance (maximize time/lb)<BR>CI = Time cost ~ $/hr<BR>Fuel cost ~ cents/lb<BR>Fuel Conservation 46<BR>Route Selection<BR>Choose the most favorable route available!<BR>Fuel Conservation 47<BR>Great Circle Distance<BR>• Shortest ground distance between 2 points on the<BR>earth’s surface<BR>• May not be the shortest time when winds are<BR>included<BR>Fuel Conservation 48<BR>ETOPS<BR>• ETOPS allows for more direct routes<BR>• Shorter routes = less fuel required<BR>New York<BR>Montreal<BR>St. Johns<BR>Goose Bay<BR>Iqaluit<BR>Kangerlussuaq<BR>Reykjavik<BR>Shannon Paris<BR>120 min<BR>60 min<BR>3148<BR>3461<BR>Using 120 min ETOPS leads to<BR>a 9% savings in trip distance!<BR>Fuel Conservation 49<BR>Fuel Tankering<BR>Fuel tankering is the practice of carrying<BR>more fuel than required for a particular<BR>sector in order to reduce the quantity of<BR>fuel loaded at the destination airport for<BR>the following sector (or sectors)<BR>What Is It?<BR>Fuel Conservation 50<BR>A B C<BR>Leg 1 Leg 2<BR>Reserves<BR>Fuel<BR>for<BR>leg 2<BR>Fuel<BR>for<BR>leg 1<BR>Fuel loaded at<BR>A for leg 1<BR>Fuel loaded at<BR>B for leg 2<BR>No tankering<BR>of 2nd leg fuel<BR>Reserves<BR>Extra fuel burned<BR>on leg 1 to carry<BR>fuel for leg 2 Fuel<BR>for<BR>leg 2<BR>Fuel<BR>for<BR>leg 1<BR>100% tankering<BR>of 2nd leg fuel<BR>Fuel loaded<BR>at A for legs 1 &amp; 2<BR>Fuel Tankering (continued)<BR>Fuel Conservation 51<BR>Reduction in total fuel costs for multiple leg<BR>flights is usually the main reason for tankering<BR>Fuel Tankering (continued)<BR>• Shorter turnaround time<BR>• Limited amount of fuel available<BR>• Unreliable airport services<BR>• Fuel quality at destination airport<BR>• Fuel price differential<BR>Why Tanker Fuel?<BR>Fuel Conservation 52<BR>Fuel Tankering (continued)<BR>• If price at departure airport is sufficiently less than at the<BR>destination airport, surplus fuel could be carried from<BR>the departure airport to lower the total fuel cost<BR>• Fuel used increases on flights where fuel is tankered<BR>such that the quantity of fuel available at landing is<BR>always less than what was originally loaded (often<BR>called ‘surplus fuel burn-off’)<BR>• Surplus fuel burn-off must be accounted for in any price<BR>differential calculation<BR>• To be cost-effective, the difference in fuel price between<BR>the departure and destination airports must be large<BR>enough to offset the cost of the additional fuel burned<BR>in carrying the tankered fuel<BR>Fuel Price Differential<BR>Fuel Conservation 53<BR>Fuel Tankering (continued)<BR>• The amount of tankered fuel loaded may<BR>be limited by:<BR>– Certified MTOW<BR>– Performance-limited MTOW<BR>– Certified MLW<BR>– Performance-limited MLW<BR>– Fuel capacity<BR>• These limits must always be checked when<BR>loading extra fuel for tankering!<BR>Limitations On Total Amounts<BR>Fuel Conservation 54<BR>Difficult to quantify, but should be<BR>addressed in all cost calculations<BR>Fuel Tankering (continued)<BR>• Lowers initial cruise altitude capability<BR>• Increases takeoff weight: higher takeoff speeds,<BR>less reduced thrust, may require improved climb<BR>• If landing is planned at or near MLW, and additional<BR>fuel burn-off was over-predicted, an overweight<BR>landing could result<BR>• Higher maintenance costs: engines, reversers,<BR>wheels, tires, brakes<BR>Additional Considerations<BR>Fuel Conservation 55<BR>To Tanker or Not to Tanker<BR>• Cost calculations vary between operators, ranging<BR>from the fairly simple to the fairly complex<BR>• Complexity of the calculations depends on the<BR>requirements of your operations. (e.g., If the<BR>decision to tanker is made by the captain at the<BR>time of fueling, a simple method is desired)<BR>• Many operators add a price per gallon, or a fixed<BR>percentage, to cover increased maintenance costs<BR>Cost Calculations<BR>Fuel Conservation 56<BR>Cost Calculations<BR>We will briefly review 3 possible methods:<BR>1) Assumed percentage burn-off<BR>2) Break-even price ratio<BR>3) Relative cost to tanker<BR>Fuel Conservation 57<BR>Cost Calculations (continued)<BR>• All methods should begin by checking whether<BR>takeoff and landing weight limits, along with fuel<BR>capacity limits, allow additional fuel to be loaded<BR>• Some operators choose a minimum tankering<BR>amount such that if the amount available to tanker<BR>is not at least equal to their chosen minimum,<BR>no fuel will be tankered<BR>Fuel Conservation 58<BR>Cost Calculations (continued)<BR>Calculation of fuel prices is not always as easy<BR>as it first appears. Understand how fuel prices are<BR>determined at your airline.<BR>For example:<BR>• Price may vary with amount purchased<BR>• Fixed hookup fees should be included (affects<BR>price per gallon - as more fuel is purchased,<BR>the hookup price/gallon decreases)<BR>• Taxes charged may be returned later as tax<BR>rebates lower the price per gallon<BR>Fuel Conservation 59<BR>‘Assumed Percentage Burn-off’ Method<BR>• Assumes a fixed percentage of the tankered fuel<BR>is consumed per hour of flight time; usually 4 to 5%<BR>per hour<BR>• Divide total cost of additional fuel purchased<BR>at departure airport by amount remaining at<BR>destination airport to determine ‘effective’ price<BR>of fuel at destination<BR>• Assume some per gallon cost to cover unknowns<BR>• Break-even price is the ‘effective’ price plus the<BR>allowance for unknown costs<BR>• If price of fuel at destination is above the breakeven<BR>price, then it is cost-effective to tanker<BR>Fuel Conservation 60<BR>Example Cost Calculation<BR>• Planned flight time = 6 hours<BR>• Departure fuel price = $1.00/gallon<BR>• Tankered fuel loaded = 40000 lb (6000 gallons)<BR>• Cost of tankered fuel = $6000<BR>• Surplus fuel burn-off (4%/hour) = 24%<BR>• Tankered fuel at landing = 6000 x .76 = 4560 gallons<BR>• Effective cost of tankered fuel = 6000/4560 = $1.32/gal<BR>• Allowance for unknown cost = $.02/gal (typical?)<BR>• Actual cost of tankered fuel = $1.32 + $.02 = $1.34/gal<BR>• Cost-effective if destination fuel price above $1.34/gal<BR>Fuel Conservation 61<BR>Trip distance (nm) Break-even price ratio<BR>200<BR>400<BR>600<BR>800<BR>1000<BR>2000<BR>3000<BR>4000<BR>5000<BR>6000<BR>1.012<BR>1.023<BR>1.034<BR>1.046<BR>1.061<BR>1.130<BR>1.217<BR>1.334<BR>1.495<BR>1.722<BR>Sample data only<BR>varies with airplane model<BR>• To economically justify tanker operation, the fuel<BR>price at the destination must be greater than the<BR>break-even fuel price<BR>Break-Even Price Ratio Method<BR>• Method used in Boeing FPPM (found in chapter 2 text)<BR>• Break-even price ratio is presented as a function of trip<BR>distance only<BR>Fuel Conservation 62<BR>$ * (tankered fuel) = $ * (tankered fuel - fuel burnoff)<BR>gal gal Orig Dest = tankered fuel<BR>remaining at dest<BR>Break-even<BR>Orig price ratio<BR>$<BR>gal Dest<BR>B.E.<BR>$<BR>Break-even price = = gal *<BR>at destination<BR>Break-Even Price Ratio Method (continued)<BR>• Break-even fuel price is the destination price at which the<BR>cost of purchasing the fuel at the destination is equivalent<BR>to the cost of purchasing the same amount of fuel, plus<BR>the fuel required to carry it, at the origin<BR>• Break-even price occurs when:<BR>Fuel Conservation 63<BR>Break-Even Price Ratio Method (continued)<BR>• If the destination fuel price is greater than the breakeven<BR>price, then it’s cheaper to tanker the fuel<BR>• The break-even price ratio does not include any<BR>allowance for additional maintenance costs; it only<BR>considers the extra fuel burn off<BR>Fuel Conservation 64<BR>Example Cost Calculation<BR>Fuel price at origin: $0.80/gal<BR>Model: 737-700/CFM56-7B24<BR>Trip distance: 2000 NM<BR>Trip distance, nm Break-even price ratio<BR>200<BR>400<BR>600<BR>800<BR>1000<BR>2000<BR>3000<BR>4000<BR>1.015<BR>1.031<BR>1.045<BR>1.059<BR>1.075<BR>1.175<BR>1.311<BR>1.477<BR>Break-even price = $0.80 ( 1.175) = $0.94<BR>If dest. fuel price &gt; $0.94, then more economical to tanker the fuel<BR>If dest. fuel price &lt; $0.94, then more economical to purchase at dest.<BR>To include increased maintenance costs, should increase the B.E.<BR>fuel price by the estimate (e.g., if unknown costs estimated at<BR>$0.02/gal, then B.E. fuel price = $0.94 + $0.02 = $0.96)<BR>Fuel Conservation 65<BR>‘Relative Cost to Tanker’ Method<BR>• Considers the difference in total cost between<BR>tankering and not tankering the fuel<BR>• Only includes costs related to tankering or not<BR>tankering fuel<BR>• Requires calculation of fuel required for actual<BR>routes with and without tankering<BR>Fuel Conservation 66<BR>A B C<BR>Leg 1 Leg 2<BR>gal<BR>A<BR>$ Fuel<BR>req’d<BR>leg 1<BR>Fuel<BR>carried<BR>for use<BR>in leg 2<BR>+<BR>Extra fuel<BR>burned on<BR>leg 1 due to<BR>extra wt<BR>+ +<BR>Additional<BR>incremental<BR>costs due to<BR>higher weight gal<BR>B<BR>$<BR>+<BR>Additional<BR>fuel req’d<BR>for leg 2<BR>*<BR>total cost with tankering<BR>-<BR>gal<BR>B<BR>Fuel $<BR>req’d<BR>leg 1<BR>-<BR>gal<BR>A<BR>$ Fuel<BR>req’d<BR>leg 2<BR>* *<BR>Total cost with no tankering<BR>‘Relative Cost to Tanker’ Method (continued)<BR>Fuel Conservation 67<BR>cost of tankering the fuel cost of purchasing<BR>at the destination<BR>gal<BR>B<BR>fuel $<BR>carried<BR>for use<BR>in leg 2<BR>+<BR>extra fuel<BR>burned on<BR>leg 1 due to<BR>extra weight<BR>+<BR>additional<BR>incremental<BR>costs due to<BR>higher weight<BR>- * gal<BR>A<BR>$<BR>fuel<BR>carried<BR>for use<BR>in leg 2<BR>‘Relative Cost to Tanker’ Method (continued)<BR>Relative cost to tanker =<BR>Fuel Conservation 68<BR>• If relative cost to tanker = 0, then breakeven<BR>• If relative cost to tanker &gt; 0, then costs are increased<BR>by tankering<BR>• If relative cost to tanker &lt; 0, then costs are reduced<BR>by tankering<BR>• Some operators choose a minimum financial gain below<BR>which there will not be tankering. (e.g., if minimum gain<BR>selected as $100, then tankering will only be used if<BR>relative cost to tanker &lt; - $100)<BR>• Multiple legs (3 or more) add significantly to the complexity<BR>of the analysis<BR>‘Relative Cost to Tanker’ Method (continued)<BR>Fuel Conservation 69<BR>Additional Applications<BR>• If fuel is tankered in order to obtain a shorter turnaround<BR>time at a given destination you can determine the<BR>relative cost of the shorter turnaround time<BR>• Cost to tanker can be used to provide flight crews<BR>with information on the cost of carrying additional,<BR>discretionary fuel<BR>‘Relative Cost to Tanker’ Method (continued)<BR>Fuel Conservation 70<BR>Fuel Tankering<BR>• Most flight planning services offer tankering<BR>analyses to their customers<BR>• You can work with your flight planning service on<BR>which assumptions to use/include, and in what form<BR>the results should be reported<BR>Fuel Conservation 71<BR>Flight Crew<BR>Opportunities for Fuel Conservation:<BR>• Practice fuel economy in each phase of flight<BR>• Understand the airplane’s systems - Systems<BR>Management<BR>Fuel Conservation 72<BR>Engine Start<BR>• Start engines as late as possible, coordinate<BR>with ATC departure schedule<BR>• Take delays at the gate if possible<BR>• Minimize APU use if ground power available<BR>Fuel Conservation 73<BR>Taxi<BR>• Take shortest route possible<BR>• Use minimum thrust and minimum braking<BR>• Taxi with all engines operating?<BR>Fuel Conservation 74<BR>Taxi<BR>• After-start and before-takeoff checklists delayed<BR>• Reduced fire protection from ground personnel<BR>• High weights, soft asphalt, taxi-way slope<BR>• Engine thermal stabilization - warm up and cool down<BR>• Pneumatic and electrical system requirements<BR>• Slow/tight turns in direction of operating engine(s)<BR>• Cross-bleed start requirements<BR>Balance fuel conservation and safety considerations<BR>One Engine Shut Down Considerations:<BR>Fuel Conservation 75<BR>Condition 727 737 747 757 767 777<BR>Taxi*<BR>(lb/min) 60 25 100 40 50 60<BR>APU<BR>(lb/min) 5 4 11 4 4 9<BR>717<BR>25<BR>4<BR>Sample Taxi and APU Fuel Burns<BR>* Assumes all engines operating during taxi<BR>Fuel Conservation 76<BR>Takeoff<BR>• Retract flaps as early as possible<BR>• Full rate or derate to save fuel?<BR>(Use of full rate will save fuel for a given takeoff, but general consensus is that in<BR>the long-term, total costs will be reduced by using reduced takeoff thrust)<BR>Fuel Conservation 77<BR>-1.0%<BR>-0.9%<BR>-0.8%<BR>-0.7%<BR>-0.6%<BR>-0.5%<BR>-0.4%<BR>-0.3%<BR>-0.2%<BR>-0.1%<BR>0.0%<BR>-25% -20% -15% -10% -5% 0%<BR>Average takeoff thrust reduction (% from full rate)<BR>Δ TSFC @ 1000 cycles<BR>Estimated Reduced Thrust<BR>Impact at 1000 Cycles<BR>15% Average Thrust Reduction Can Improve<BR>Overall TSFC at 1000 Cycles by over 0.4%<BR>(Courtesy of Pratt &amp; Whitney)<BR>Reduced Take Off Thrust<BR>Improves Long-term Performance Retention<BR>Fuel Conservation 78<BR>Distance<BR>Altitude<BR>Initial cruise<BR>altitude<BR>Cost index<BR>increasing<BR>A<BR>B<BR>CI = 0 (Min fuel)<BR>Min time to Point B<BR>Max gradient<BR>Climb<BR>Cost Index = 0 minimizes fuel to climb and<BR>cruise to a common point in space<BR>Fuel Conservation 79<BR>Cruise<BR>• A plane flying in steady, level flight may require<BR>some control surface inputs to maintain lateraldirectional<BR>control<BR>• Use of the proper trim procedure<BR>minimizes drag<BR>• Poor trim procedure can<BR>result in a 0.5% cruise<BR>drag penalty on a 747<BR>• Follow the procedures<BR>provided in the Flight<BR>Crew Training Manual<BR>Lateral - Directional Trim Procedure<BR>Fuel Conservation 80<BR>Systems Management<BR>Cruise<BR>• A/C packs in high flow typically produce<BR>a 0.5 - 1 % increase in fuel burn<BR>• Do not use unnecessary cargo heat<BR>• Do not use unnecessary anti-ice<BR>• Maintain a balanced fuel load<BR>Fuel Conservation 81<BR>Winds<BR>Cruise<BR>• Wind may be a reason to choose an “off<BR>optimum” altitude<BR>• Want to maximize ground miles per unit<BR>of fuel burned<BR>• Wind-Altitude trade tables are provided<BR>in the flight crew operations manual<BR>Fuel Conservation 82<BR>Fuel Mileage = =<BR>Fuel Flow<BR>VTAS<BR>KG<BR>NAM<BR>Fuel Used = =<BR>NGM/KG<BR>NGM<BR>NAM/KG<BR>NAM =<BR>VTAS + VWIND<BR>(NGM) (Fuel Flow)<BR>Ground Fuel Mileage = =<BR>Fuel Flow<BR>VTAS + VWIND<BR>KG<BR>NGM<BR>In cruise: positive wind = Tailwind<BR>negative wind = Headwind<BR>VGround<BR>Wind Effects On Fuel Mileage<BR>Fuel Conservation 83<BR>Typical Wind/Altitude Trade Table<BR>Wind Effects On Cruise Altitude: Wind/Alt Trade<BR>33 knots greater tailwind (or,<BR>lower headwind) would be<BR>required at FL310 relative to<BR>FL350 to obtain equivalent<BR>ground fuel mileage<BR>Fuel Conservation 84<BR>MACH number<BR>Ground fuel mileage<BR>.80 .81 .82 .83 .84 .85 .86<BR>64<BR>66<BR>68<BR>70<BR>72<BR>74<BR>76<BR>78<BR>35K, Wind = 0<BR>31K, Wind = 0<BR>MACH number<BR>Ground fuel mileage<BR>.80 .81 .82 .83 .84 .85 .86<BR>64<BR>66<BR>68<BR>70<BR>72<BR>74<BR>76<BR>78<BR>35K, Wind = 0<BR>31K, Wind = 0<BR>Wind = 10<BR>Wind = 20<BR>Wind = 30<BR>Wind = 40<BR>LRC, 35K<BR>Typical Wind Altitude/Trade for Constant Airplane Weight<BR>Example of increasing Tailwind at 31,000 ft Example of increasing headwind at 35,000 ft<BR>LRC, 31K<BR>LRC, 31K<BR>LRC, 35K<BR>Wind = -10<BR>Wind = -20<BR>Wind = -30<BR>Wind = -40<BR>Wind Effects On Cruise Altitude: Wind/Alt Trade<BR>* Actual ground fuel mileage comparisons vary with airplane model,<BR>weight, and altitudes considered<BR>Fuel Conservation 85<BR>Ground fuel mileage<BR>60<BR>80<BR>100<BR>120<BR>140<BR>160<BR>180<BR>200<BR>220<BR>240<BR>.72 .73 .74 .75 .76 .77 .78 .79 .80 .81 .82<BR>MACH number<BR>Zero wind<BR>100 kt headwind<BR>200 kt headwind<BR>100 kt tailwind<BR>MRC<BR>LRC<BR>Typical affect of wind on ground fuel mileage when<BR>flying a constant altitude and weight<BR>Wind Effects On Cruise Mach Number<BR>Zero wind LRC<BR>* Actual ground fuel mileage comparisons vary with airplane model,<BR>weight, and altitudes considered<BR>Fuel Conservation 86<BR>Descent<BR>• Penalty for early descent - spend more time at low<BR>altitudes, higher fuel burn<BR>• Optimum top of descent point is affected by wind,<BR>ATC, speed restrictions, etc.<BR>• Use information provided by FMC<BR>• Use idle thrust (no part-power descents)<BR>Fuel Conservation 87<BR>Distance<BR>Final cruise<BR>altitude<BR>Cost index<BR>increasing<BR>B<BR>CI = 0 (Min fuel)<BR>Min time from point A to B<BR>Descent<BR>Cost Index = 0 minimizes fuel between a common<BR>cruise point and a common end of descent point<BR>Altitude<BR>A<BR>Fuel Conservation 88<BR>Approach<BR>• Do not transition to the landing configuration<BR>too early<BR>• Fuel flow in the landing configuration is<BR>approximately 150% of the fuel flow in the<BR>clean configuration<BR>Fuel Conservation 89<BR>Summary Of Operational Practices<BR>• Minimize landing weight<BR>• Do not carry more reserve fuel than required<BR>• Use aft C.G. loading if possible<BR>• Use lowest flap setting required<BR>• Target optimum altitude (wind-corrected)<BR>• Target LRC (or cost index)<BR>• Choose most direct routing<BR>• Use benefits of ETOPS routing<BR>• Use tankering where appropriate<BR>Flight Operations / Dispatchers<BR>Fuel Conservation 90<BR>Flight Crews<BR>Summary Of Operational Practices<BR>• Minimize engine/APU use on ground<BR>• Retract Flaps as early as possible<BR>• Fly the flight-planned speeds for all<BR>phases of flight<BR>• Use proper trim procedures<BR>• Understand the airplane’s systems<BR>• Understand wind/altitude trades<BR>• Don’t descend too early (or too late)<BR>• Don’t transition to landing configuration<BR>too early<BR>Maintenance Practices for<BR>Fuel Conservation<BR>Fuel Conservation 92<BR>Opportunities For Fuel Conservation<BR>Maintenance Personnel<BR>• Airframe maintenance<BR>• Engine maintenance<BR>• Systems maintenance<BR>Fuel Conservation 93<BR>Excess Drag Is Lost Payload<BR>Fuel Conservation 94<BR>Exxcceessss Drraagg Meeaannss Waasstteedd Fuueell<BR>• 747 ≈ 100,000<BR>• 777 ≈ 70,000<BR>• 767 ≈ 30,000<BR>• 757 ≈ 25,000<BR>• 737 ≈ 15,000<BR>• 727 ≈ 30,000<BR>1% Drag In Terms Of Gallons Per Year<BR>* Assumes typical airplane utilization rates. Actual utilization rates may differ.<BR>Fuel Conservation 95<BR>Total Drag Is Composed Of:<BR>Compressible drag ≈ drag due to Mach<BR>• Shock waves, separated flow<BR>Induced (vortex) drag ≈ drag due to lift<BR>• Downwash behind wing, trim drag<BR>Parasite drag ≈ drag not due to lift<BR>• Shape of the body, skin friction, leakage,<BR>interference between components<BR>• Parasite drag includes excrescence drag<BR>Fuel Conservation 96<BR>Drag due to<BR>airplane size<BR>and weight<BR>(unavoidable)<BR>~ 90%<BR>Pressure, trim and<BR>interference drag<BR>(optimized in the<BR>wind tunnel)<BR>~ 6%<BR>Excrescence drag<BR>(this can increase)<BR>~ 4%<BR>Contributors To Total Airplane Drag<BR>(New Airplane at Cruise Conditions)<BR>* Typical values for illustration purposes. Actual magnitudes vary with airplane model<BR>Fuel Conservation 97<BR>What Is Excrescence Drag?<BR>The additional drag on the airplane due<BR>to the sum of all deviations from a<BR>smooth sealed external surface<BR>Proper maintenance can prevent an<BR>increase in excrescence drag<BR>Fuel Conservation 98<BR>0<BR>1<BR>2<BR>3<BR>4<BR>Excrescence drag<BR>(% airplane drag)<BR>Discrete items<BR>Mismatches<BR>and gaps<BR>Internal airflow &amp; seal<BR>leakage<BR>Roughness &amp;<BR>surface irregularities<BR>Excrescence Drag On<BR>A ‘New Airplane’ Is Composed Of:<BR>Total<BR>* Typical values for illustration purposes. Actual magnitudes vary with airplane model<BR>Fuel Conservation 99<BR>Discrete Items<BR>• Antennas, masts, lights<BR>• Drag is a function of design, size, position<BR>Fuel Conservation 100<BR>Mismatched Surfaces<BR>Steps and gaps at skin joints, around windows, doors,<BR>control surfaces, and access panels<BR>Frame<BR>Skin<BR>Fuel Conservation 101<BR>Internal Airflow<BR>Leaks from higher to lower<BR>pressure areas due to<BR>deteriorated or poorly-installed<BR>aerodynamic seals<BR>Aiirrffllow<BR>Fuel Conservation 102<BR>Roughness<BR>(Particularly Bad Near Static Sources)<BR>• Non-flush fasteners, rough surface<BR>• Waviness, gaps<BR>Non Flush Rivet Rough Surface<BR>Waviness Gaps<BR>Fuel Conservation 103<BR>Most Important in Critical Areas<BR>• Forward portion of fuselage and nacelle<BR>• Leading areas of wings and tail<BR>• Local Coefficient of Pressure (Cp) is highest<BR>All spoilers up<BR>3.75” = 2% drag<BR>Outboard aileron up<BR>4” = 1% drag<BR>Rudder deflection<BR>4.5 degrees<BR>(offset 9.5” at base)<BR>=2% drag<BR>1” tall ridge on wing<BR>75 ft. long = 2% drag<BR>747 Cruise Drag Sensitivities<BR>Fuel Conservation 104<BR>Regular Maintenance Minimizes Deterioration<BR>• Flight control rigging<BR>• Misalignments and mismatches<BR>• Aerodynamic seals<BR>• Exterior surface finish<BR>• OEW control<BR>• Engine maintenance<BR>• Instrument calibration<BR>Fuel Conservation 105<BR>Flight Control Rigging<BR>Out of rig controls and flaps can cause a large<BR>increase in fuel burn<BR>747-400 examples:<BR>• Aileron 1” out of rig ≈ 0.25% fuel<BR>• Spoilers 1,2,3 and 4 up 2” ≈ 0.4% fuel<BR>• Upper and lower rudder offset ≈ 0.35% fuel<BR>• Inboard elevator 2” out of rig ≈ .4% fuel<BR>Fuel Conservation 106<BR>In-Flight Inspections Can be Easily Made<BR>Several times during flight:<BR>• Note required aileron and rudder trim ≈ 5 minutes<BR>• Visual check of spoiler misfair ≈ 5 minutes<BR>• Visual check of trailing edge of wing ≈ 10 minutes<BR>Fuel Conservation 107<BR>Misrigged Ailerons<BR>Misrigged outboard ailerons can result<BR>in an increase in drag and fuel flow<BR>Fuel Conservation 108<BR>Spoilers<BR>The spoilers can begin to rise if the aircraft is<BR>balanced by excessive autopilot lateral input<BR>Fuel Conservation 109<BR>Control Surface Rigging Check<BR>747 example (includes fit and fair check):<BR>• Ailerons ≈ 4 hours (1 - 2 people)<BR>• Spoilers ≈ 2 hours (2 people)<BR>• Flaps and Slats ≈ 3 hours (1 - 2 people)<BR>• Rudders ≈ 3 hours (1 - 2 people)<BR>• Elevators ≈ 2 hours (2 people)<BR>Fuel Conservation 110<BR>Misalignment, Mismatch<BR>Check items which are adjustable and could<BR>become misaligned after years of service:<BR>• Adjustable panels<BR>• Landing gear doors<BR>• Entry doors and cargo doors<BR>Fuel Conservation 111<BR>Surface Mismatch<BR>Surface Mismatch – ADF Antenna Fairing – negative step<BR>Fuel Conservation 112<BR>Surface Mismatch<BR>Engine inlet secondary inlet door mismatch – positive step<BR>Fuel Conservation 113<BR>Leading Edge Mismatch<BR>727 surface mismatch-R.H. Wing leading edge<BR>slat actuator rod cover - positive step<BR>Airflow<BR>Fuel Conservation 114<BR>Positive Step and Improper Seal<BR>727 surface mismatch - lower wing critical area<BR>(flap track fairing - fabricated leather seal) - positive step<BR>Airflow<BR>Fuel Conservation 115<BR>Check for Tight Aircraft Doors<BR>Note the tight and even fit of the air<BR>conditioning compartment access doors<BR>Fuel Conservation 116<BR>Maintain Seals<BR>• Passenger and cargo door seals<BR>• Damaged seals allow air to leak out<BR>• Lose ‘thrust recovery’ from outflow valves<BR>• Disrupts flow along the fuselage<BR>Passenger<BR>doors<BR>Fwd cargo<BR>door seal<BR>depressor<BR>before repair<BR>Fuel Conservation 117<BR>Check for Missing or Damaged Seals<BR>747 R.H. Wing gear well door forward<BR>outboard seal missing and damaged<BR>Airflow<BR>Fuel Conservation 118<BR>Check for Rough Surface Paint<BR>747 rough paint - lower fuselage<BR>Airflow<BR>Fuel Conservation 119<BR>Maintain a Clean Airplane<BR>• Maintain surface finish<BR>• Fluid leaks contribute to drag<BR>• Periodic washing of exterior<BR>is beneficial<BR>– 0.1% drag reduction if<BR>excessively dirty<BR>– Minimizes metal corrosion<BR>and paint damage<BR>– Location of leaks and local<BR>damage<BR>• Customer aesthetics<BR>Fuel Conservation 120<BR>Make Simple Inspections<BR>• Seal inspections ≈ 1 hour<BR>• Nacelles and struts ≈ 2 hours<BR>• Wing/body/tail misfairs ≈ 2 hours<BR>• General roughness and appearance ≈ 1 hour<BR>• Pressurized fuselage leak ≈ 2 hours<BR>• Landing gear door check ≈ 1.5 hours<BR>Fuel Conservation 121<BR>Average Results Of In-service Drag Inspections<BR>• Results of in-service airframe drag inspections show the<BR>most common contributors to airframe deterioration are:<BR>– Control surface miss-rigging<BR>– Aerodynamic seal deterioration<BR>• Lesser contributors include:<BR>– Skin surface miss-matches<BR>– Surface roughness<BR>– ‘Other’<BR>Fuel Conservation 122<BR>OEW Control<BR>• Operating empty weight (OEW) typically increases<BR>0.1% to 0.2% per year, leveling off around +1% from<BR>a new-airplane level in 5 to 10 years<BR>• Most OEW growth is mainly due to accumulation of:<BR>– Moisture<BR>– Dirt<BR>Fuel Conservation 123<BR>Engine Maintenance<BR>• Need to balance savings from performance<BR>improvements versus cost to perform maintenance<BR>• Maintenance performed on high and low pressure<BR>turbines and compressors will help keep fuel<BR>consumption from deteriorating<BR>Fuel Conservation 124<BR>Items That Cause Engine/Fuel Burn<BR>deterioration<BR>Erosion / Wear / Contamination<BR>• Blade rubs - HP compressor, HP turbine, airfoil blade erosion<BR>• Thermal distortion of blade parts<BR>• Blade leading edge wear<BR>• Excessive fan rubstrip wear<BR>• Lining loss in the HP compressor<BR>• Oil or dirt contamination of LP/HP compressor<BR>Seals / Valves / Cooling<BR>• Loss of High Pressure Turbine (HPT) outer air seal material<BR>• Leaking thrust reverser seals<BR>• ECS anomalies/leaks<BR>• Failed-open fan air valves/Failed-open IDG air-oil cooler<BR>valves<BR>• Faulty turbine case cooling/Faulty 11th stage cooling valves<BR>Fuel Conservation 125<BR>Engine Components Are Affected By The<BR>Environment In Which They Operate<BR>Fuel Conservation 126<BR>Typical Engine Deterioration Mechanisms<BR>Increased tip<BR>clearances<BR>Seal leakage<BR>Airfoil<BR>erosion<BR>Dirt<BR>accumulation<BR>(Courtesy of Pratt &amp; Whitney)<BR>Fuel Conservation 127<BR>Scheduled Refurbishing Recovers SFC and EGT<BR>(Courtesy of Pratt &amp; Whitney)<BR>SFC<BR>or<BR>EGT<BR>Hours or cycles<BR>Shop<BR>visit<BR>Shop<BR>visit<BR>Fuel Conservation 128<BR>Simple Procedures Can Recover Performance<BR>Between Scheduled Shop Visits<BR>On-Wing Engine Washing<BR>• Addresses dirt accumulation<BR>On-Wing Engine Bleed Rigging<BR>• Addresses leakage caused by bleed<BR>system wear<BR>(Courtesy of Pratt &amp; Whitney)<BR>Fuel Conservation 129<BR>On-Wing Engine Washing<BR>• Simple procedure<BR>• Special tooling identified<BR>• 3-4 hours, two mechanics<BR>Up to 1.5% SFC<BR>improvements<BR>possible<BR>Hand wash fan and<BR>LPC stator vanes<BR>Regular Intervals Ensure Fuel Economy<BR>(Courtesy of Pratt &amp; Whitney)<BR>Fuel Conservation 130<BR>0.0<BR>0.5<BR>1.0<BR>1.5<BR>2.0<BR>2.5<BR>3.0<BR>3.5<BR>4.0<BR>0 1000 2000 3000 4000 5000 6000<BR>Cycles<BR>% ΔTSFC<BR>1000 cycle wash<BR>Unwashed<BR>500 cycle wash<BR>0.5%<BR>1000 cycle wash<BR>cumulative benefit<BR>0.75%<BR>500 cycle wash<BR>cumulative benefit<BR>Example of Water Wash Frequency Impact<BR>SFC and EGT Can Be Recovered Between Shop<BR>Visits Using Repetitive Engine Washes<BR>(Courtesy of Pratt &amp; Whitney)<BR>Fuel Conservation 131<BR>On-Wing Engine Bleed Rigging<BR>• Simple procedure<BR>• Start, stability, service bleeds<BR>• Problem Identified from in-flight<BR>performance trends<BR>Up to 2.5% SFC benefit<BR>possible<BR>Repair of Leaking Bleed Valves Saves Fuel<BR>(Courtesy of Pratt &amp; Whitney)<BR>Fuel Conservation 132<BR>Instrument Calibration<BR>• Speed measuring equipment has a large impact<BR>on fuel mileage<BR>• If speed is not accurate the airplane may be flying<BR>faster or slower than intended<BR>• On the 747-400, flying 0.01M faster can increase<BR>fuel burn by 1% or more<BR>Fuel Conservation 133<BR>Airspeed System Error Penalty<BR>• Keep airspeed system calibrated<BR>• Airspeed reads 1% low, airplane flies 1% fast<BR>• About 2% drag penalty in a 747<BR>Fuel Conservation 134<BR>Plugging or deforming the holes in the alternate static port can result<BR>in erroneous instrument readings in the flight deck. Keeping the<BR>circled area smooth and clean promotes aerodynamic efficiency.<BR>Check Static Sources<BR>Fuel Conservation 135<BR>Don’t let this…<BR>Become this!<BR>Proper and Continuous Airframe and Engine Maintenance<BR>Will Keep Your Airplanes Performing at Their Best!<BR>Fuel Conservation 136<BR>It Takes the Whole Team to Win<BR>Conclusions<BR>• Large fuel savings results from the accumulation<BR>of many smaller fuel-saving actions and policies<BR>• Dispatch, flight operations, flight crews, maintenance,<BR>and management all need to contribute<BR>• Program should be tailored to your airline’s needs and<BR>requirements<BR>Fuel Conservation 137<BR>For More Information<BR>• Airliner Magazine<BR>– 1958 to 1997<BR>• Newsletters (self-contained inserts in the Airliner Magazine)<BR>– Fuel Conservation Newsletter - January 1981 to<BR>December 1983<BR>– Fuel Conservation &amp; Operations Newsletter - January 1984<BR>to June 1994<BR>– Operations Newsletter - July 1994 to December 1997<BR>• Aero Magazine (replaced Airliner after Boeing - MDC merger)<BR>– January 1998 to 2003<BR>Boeing has published numerous articles addressing fuel<BR>conservation over the last 4 decades in the following publications:<BR>End of<BR>Fuel Conservation<BR>Flight Operations Engineering<BR>Boeing Commercial Airplanes<BR>November 2004
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