标题: in flight performance 空中性能 [打印本页] 作者: 航空 时间: 2010-7-25 16:17:10 标题: in flight performance 空中性能
in flight performance 空中性能
作者: 航空 时间: 2010-7-25 16:17:29
A project supported by AIRBUS and the CAAC Date of the module • Table of contents • Flight operations duties • European Applicable Regulation • General • General aircraft limitations • Payload Range • Operating limitations • In flight performance • One engine inoperative performance • Flight planning • weight and balance A project supported by AIRBUS and the CAAC Date of the module Table of Contents 1 - Cruise 2 - Climb 3 - Descent 4 - Holding A project supported by AIRBUS and the CAAC Date of the module Table of Contents 1 - Cruise 2 - Climb 3 - Descent 4 - Holding A project supported by AIRBUS and the CAAC Date of the module 1 - - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 – ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module 1 - - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 – ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module Titre du diagramme Safety Respecting official requirements .Operating rules .Airworthiness Economy Lowering direct operating costs . Choice of speed . Choice of flight levels 2 goals OEI cruise AEO cruise A project supported by AIRBUS and the CAAC Date of the module 1 - Direct Operating Costs(DOC) Direct Operating costs are made of : Fixed costs cyclic maintenance costs airport and en-route taxes operating charges, insurance, etc... Flight time related costs hourly maintenance costs crew costs Fuel consumption related costs A project supported by AIRBUS and the CAAC Date of the module Titre du diagramme Lower fuel consumption Fuel consumption related costs Lower flight time Flight time related costs Minimize direct operating costs Compromise Time / Fuel A project supported by AIRBUS and the CAAC Date of the module 1 - Direct Operating Costs (DOC) Specific range study : versus Mach number, at given altitude Mach number optimization versus altitude, at given Mach number optimum altitude A project supported by AIRBUS and the CAAC Date of the module 1 - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 – ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module 2 - Specific Range SR = 1 Distance consumption Unit : nm / ton or nm / 1000 lbs Example : A320-200 SR = 200 nm / ton (58 tons at FL 350 M.78) A project supported by AIRBUS and the CAAC Date of the module 2 - Specific Range SR = SR = 1 Distance consumption Ground speed Hourly consumption A project supported by AIRBUS and the CAAC Date of the module 2 - Specific Range SR = SR = With no wind SR = 1 Distance consumption Ground speed Hourly consumption TAS Ch A project supported by AIRBUS and the CAAC Date of the module T To speed of sound temperature 2 - Specific Range TAS = a.M and a = ao A project supported by AIRBUS and the CAAC Date of the module 2 - Specific Range TAS = a.M and a = ao T To 661 kt 288 °K A project supported by AIRBUS and the CAAC Date of the module TAS= a.M and a = ao Ch = Csp. Ta and Ta = T To Specific consumption Engine thrust available Lift to Drag ratio mg L/D A project supported by AIRBUS and the CAAC Date of the module TAS= a.M and a = ao Ch = Csp. Ta and Ta = T To mg L/D mg L/D T To ao M Csp SR = A project supported by AIRBUS and the CAAC Date of the module SR = ao M L/D Csp T To mg 2 - Specific Range Aerodynamics Engine Weight A project supported by AIRBUS and the CAAC Date of the module SR variations with Mach number M.L/D Csp T To .70 .80 .90 Mach 0,075 Csp T To 0,085 (kg/h.N) 10 15 M.L/D Given : - weight - altitude 2 - Specific Range A project supported by AIRBUS and the CAAC Date of the module SR variations with Mach number Mach SR .70 .80 .90 100 150 200 250 (nm/t) Given : - weight - altitude SR max Maxi-range Mach SR reaches a maximum 2 - Specific Range A project supported by AIRBUS and the CAAC Date of the module 1 - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 – ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module Mach SR All along the flight, the fuel consumption makes the aeroplane weight decrease Maxi-Range influence of weight Given : - altitude 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Mach SR burn off Maxi-Range Given : - altitude 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Mach SR burn off Maxi-Range Given : - altitude 3 - All engines operating cruise speeds As weight decreases, - the specific range increases - the Maxi-Range Mach decreases too A project supported by AIRBUS and the CAAC Date of the module Mach SR burn off Maxi-Range Cd minimum : trip fuel is minimum but low speed : trip time is quite long ! Given : - altitude 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Mach SR burn off Maxi-Range Cd minimum : trip fuel is minimum but low speed : trip time is quite long ! Alternative : Increasing cruise speed without too much increasing of fuel consumption Given : - altitude Long-Range 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Decrease of 1% in SR max Long-Range Mach SR .70 .80 .90 -1% MR LR Given : - altitude Flying at Long-Range cruise enables a greater speed than MR, and a relatively low fuel consumption 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Long-Range : influence of weight Long-Range Mach decreases the same way as MR Mach Mach SR .70 .80 .90 -1% -1% -1% LRC burn off Given : MR - altitude 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module -1% -1% -1% Constant Mach : Mach SR .70 .80 .90 LRC burn off constant M Given : MR - altitude 3 - All engines operating cruise speeds easier to remember ! (it is the same whatever altitude and weight are) but doesn't follow the optimum (especially when there is no change in altitude) A project supported by AIRBUS and the CAAC Date of the module Goal : minimize D.O.C. 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Goal : minimize D.O.C. For a given trip : Fuel consumption related costs : CF . TF CF : Cost of fuel unit TF : Trip fuel 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Goal : minimize D.O.C. For a given trip : Fuel consumption related costs : CF . TF Flight time related costs : CT . t CT : Time related costs per flight hour – hourly maintenance costs – crew wages t : Block time 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Goal : minimize D.O.C. For a given trip : Fuel consumption related costs : CF . TF Flight time related costs : CT . t Fixed costs : CC cyclic maintenance costs airport operational taxes operating charges, insurance... 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Goal : minimize D.O.C. For a given trip : Fuel consumption related costs : CF . TF Flight time related costs : CT . t Fixed costs : CC DOC = CF . TF + CT . t + CC 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module For one nautical mile : DOC1nm = CF . 1+ CT . 1 + V CC D Fuel consumption related costs Time related costs Fixed costs SR 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Costs Mach MR LRC Cost of fuel Cost of time Fixed costs ECON Given weight and altitude DOC 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Costs Mach ECON MR LRC Cost of fuel Cost of time Fixed costs Given weight and altitude ECON Mach is linked to MR Mach : DOC when aircraft weight decreases, ECON Mach decreases. 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Minimum DOC : dDOC dM = 0 3 - All engines operating cruise speeds 1 dDOC SR dM = CF + CT -1 aM2 d( ) dM A project supported by AIRBUS and the CAAC Date of the module Minimum DOC : 1 SR CF d( ) dM + CT -1 aM2 = 0 M2 1 SR d( ) dM = CT CF 1a COST INDEX 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module The ECON Mach depends on COST INDEX 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module The ECON Mach depends on COST INDEX Cost of time Cost of fuel C.I. = 3 - All engines operating cruise speeds Unit : kg / mn Range : 0 to 200 A project supported by AIRBUS and the CAAC Date of the module Extreme values of cost index : C.I. = 0 MR Mach C.I. max Maximum Mach Number 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module Extreme values of cost index : C.I. = 0 MR Mach C.I. max Maximum Mach Number Increase in cost index Increase in Mach 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module ECON Mach MR Mach At constant Zp , when weight decreases, ECON Mach does so At constant weight, when Zp increases, ECON Mach does so 3 - All engines operating cruise speeds A project supported by AIRBUS and the CAAC Date of the module 1 - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 – ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module SR = ao M L/D Csp T To mg When Zp increases, for a given aircraft weight, SR follows lift-to-drag ratio variations. (without taking into account the low variations of reduced Csp ) For a given Mach number : constant At level flight : mg = 0,7 S P CL M2 When Zp increases (P decreases), then CL must be increased 4 -Altitude optimisation A project supported by AIRBUS and the CAAC Date of the module CL M lift-to-drag ratio increases... When Zp increases, CL must increase CD 4 -Altitude optimisation A project supported by AIRBUS and the CAAC Date of the module CL M CL Lift-to-drag increases, reaches a maximum, and then decreases SR increases, reaches a maximum, and then decreases Zp SR m M L/D max CD 4 -Altitude optimisation A project supported by AIRBUS and the CAAC Date of the module SR m M For the given Mach and weight, there is an optimum altitude at which the aircraft has the best lift-to-drag ratio. Optimum altitude CL Zp M CL L/D max CD 4 -Altitude optimisation A project supported by AIRBUS and the CAAC Date of the module When weight decreases SR increases At optimum altitude : L/D max CL fixed With burn off : mg = 0,7 S P CL M2 constant 4 -Altitude optimisation A project supported by AIRBUS and the CAAC Date of the module When weight decreases SR increases At optimum altitude : L/D max CL fixed With burn off : At optimum altitude : mP is constant 4 -Altitude optimisation mg = 0,7 S P CL M2 constant A project supported by AIRBUS and the CAAC Date of the module Optimum altitude : Zp SR m1 m > m2 mP = ct SR increases with burn off Optimum altitude increases too 4 -Altitude optimisation A project supported by AIRBUS and the CAAC Date of the module Optimum altitude : Zp SR Optimum altitude m1 > m2 > m3 Zp weight burn off mP = ct 4 -Altitude optimisation A project supported by AIRBUS and the CAAC Date of the module 1 - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 – ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module ISA + 20 Engine limitation Maximum Cruise Thrust ISA or below MCrT limits Cruise Mach SR M Zp1 m3 m2 m1 At weight m2, with cruise Mach, MCT cruise is reached at Zp1. 5 - Maximum cruise altitude A project supported by AIRBUS and the CAAC Date of the module SR M m3 m2 m1 ISA or below ISA + 20 ISA + 20 ISA or below Cruise Mach Engine limitation Maximum Cruise Thrust MCrT limits Zp1 SR M m3 m2 m1 Cruise Mach Zp2 > Zp1 MCrT is more limitative at higher altitude 5 - Maximum cruise altitude A project supported by AIRBUS and the CAAC Date of the module SR M m3 m2 m1 ISA + 20 ISA or below Cruise Mach Engine limitation Maximum Cruise Thrust Flying at Zp2, with the same weight would require a thrust higher than MCrT Zp2 > Zp1 5 - Maximum cruise altitude A project supported by AIRBUS and the CAAC Date of the module SR M m3 m2 m1 ISA + 20 ISA or below Cruise Mach Engine limitation Maximum Cruise Thrust Only lighter weights can be flown at higher altitude with the same cruise Mach Zp2 > Zp1 5 - Maximum cruise altitude A project supported by AIRBUS and the CAAC Date of the module SR M m3 m2 m1 ISA + 20 ISA or below Cruise Mach Engine limitation Maximum Cruise Thrust Zp2 is the maximum cruise altitude for m3 in ISA condition, at this cruise Mach number Zp2 > Zp1 5 - Maximum cruise altitude A project supported by AIRBUS and the CAAC Date of the module Definition : For a given aircraft weight, it is the maximum altitude at maximum cruise thrust in level flight with a given Mach number . 5 - Maximum cruise altitude = f(temp.) A project supported by AIRBUS and the CAAC Date of the module ISA or below ISA + 20 Maximum cruise altitude decreases when : - weight increases - temperature increases - Mach increases Zp weights Max cruise altitude M 5 - Maximum cruise altitude A project supported by AIRBUS and the CAAC Date of the module Zp weights ISA or below ISA + 20 Max cruise altitude engine-limited area M 5 - Maximum cruise altitude A project supported by AIRBUS and the CAAC Date of the module Cruise at ECON MACH Zp weights ISA or below ISA + 20 Max cruise altitude Optimum altitude ECON Mach iso-Mach curves M 5 - Maximum cruise altitude Mach depends on : altitude weight iso-Mach curves are parallel to optimum altitude A project supported by AIRBUS and the CAAC Date of the module Effect of wind on optimum altitude : if wind is more favourable at lower altitude, it may be worth flying at this altitude to increase the ground specific range. Zp weights ISA or below ISA + 20 Max cruise altitude Optimum altitude wind deviation for constant ground SR 20 40 60 A project supported by AIRBUS and the CAAC Date of the module 1 - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 - ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module LIFT RANGE : On level flight mg = 0.7 S P CL M2 When CL = CLmax lift limit (if increases, stall occurs) Lift range is associated with CLmax M2 curve 6 - Buffet limit A project supported by AIRBUS and the CAAC Date of the module 1 CL max M2 M 1 CL max M Compressibility effect 6 - Buffet limit A project supported by AIRBUS and the CAAC Date of the module CL max M2 M 1 mg = 0.7 S P CLmaxM2 given weight Zp lift range Mmin Mmax Zp max Lift ceiling Level flight (no load factor) 6 - Buffet limit At given weight, to each CLmax M2 corresponds one altitude (static Pressure) When Zp increases, the lift range decreases. lift ceiling A project supported by AIRBUS and the CAAC Date of the module While maneuvering, the aeroplane suffers load factors mg n mg buffet limit : n mg = 0.7 S P CLmaxM2 buffet = severe vibrations just before stall occurs 6 - Buffet limit At given altitude, and given weight, to each CLmaxM2 corresponds one load factor A project supported by AIRBUS and the CAAC Date of the module Mach n Zp1 given weight 6 - Buffet limit Mmin Mmax n1 At given weight and altitude, the aeroplane can suffer a load factor equal to n1 before buffeting at Mmin (or Mmax). A project supported by AIRBUS and the CAAC Date of the module Mach n FL 350 given weight : 60t Example : A320 200 Mmin= 0.65 Mmax> MMO (0.84) 1.3 g 6 - Buffet limit 1.3 g corresponds to a bank angle of 39° A project supported by AIRBUS and the CAAC Date of the module Mach n Zp1 Mmin Mmax n1 given weight At given altitude and given weight, there is a maximum admissible load factor 6 - Buffet limit nmax M This Mach allows the higher load factor margin with buffet limit A project supported by AIRBUS and the CAAC Date of the module Mach n FL 350 Mmax> MMO given weight : 60t Example : A320 200 1.3 g Mmin= 0.65 0.78 1.8 g 6 - Buffet limit A project supported by AIRBUS and the CAAC Date of the module Mach n at Zp1 Zp1< Zp2< Zp3 1.3 g Mmin Mmax given weight Effect of altitude : nmax decreases lift range decreases 6 - Buffet limit at Zp2 Zp3 At Zp3 nmax = 1.3g A project supported by AIRBUS and the CAAC Date of the module 1.3 g buffet limited altitude : at this altitude, nmax = 1.3 g (or bank angle = 39°) above this altitude, maneuvers of less than 1.3 g will create buffeting when the weight decreases (burn off), 1.3 g buffet limited altitude increases 6 - Buffet limit A project supported by AIRBUS and the CAAC Date of the module Zp weights Optimum altitude ISA or below ISA + 20 Max cruise altitude 1.3 g buffet limit The maximum operational altitude is the lowest of : max cruise altitude 1.3 g buffet limited altitude 6 - Buffet limit A project supported by AIRBUS and the CAAC Date of the module 7. ATC Requirment Flight Level Final chosen maximum flight altitude is a adjacent flight level A project supported by AIRBUS and the CAAC Date of the module 1 - Direct operating cost 2 - Specific range 3 - All engines operating cruise speeds 4 - Altitude optimisation 5 - Maximum cruise altitude 6 - Buffet limit 7 – ATC requirment 8 - Cruise optimisation Table of Contents A project supported by AIRBUS and the CAAC Date of the module Step climb cruise : Ideal cruise should follow the optimum altitude but ATC constraints require level flight cruise airlines have to comply with Zp weight Optimum altitude several level flights close to the optimum altitude 8 - Cruise optimisation A project supported by AIRBUS and the CAAC Date of the module Zp weight 4000 ft Above FL290 : FL separation = 2000 ft step climb = 4000 ft (except RVSM zones) Optimum altitude 8 - Cruise optimisation 2000 ft from optimum altitude : Rs = 99% Rsmax Long flight : 2 or 3 steps Max cruise altitude can delay the first climb... A project supported by AIRBUS and the CAAC Date of the module Table of Contents 1 - Cruise 2 - Climb 3 - Descent 4 - Holding A project supported by AIRBUS and the CAAC Date of the module 1 - Climb angle and rate of climb 2 - Climb in operation 3 - Influencing parameters 4 - Cabin climb Table of Contents A project supported by AIRBUS and the CAAC Date of the module 1 - Climb angle and rate of climb 2 - Climb in operation 3 – Influencing parameters 4 - Cabin climb Table of Contents A project supported by AIRBUS and the CAAC Date of the module TAS rate of climb TASmax TASRCmax Maximum rate of climb Given m, thrust, operationnal data max = maximum air climb gradient 1 - Climb angle and rate of climb A project supported by AIRBUS and the CAAC Date of the module g a <g GS a TAS Rate of Climb RC 1 - Climb angle and rate of climb Headwind A project supported by AIRBUS and the CAAC Date of the module 1 - Climb angle and rate of climb 2 - Climb in operation 3 – Influencing parameters 4 - Cabin climb Table of Contents A project supported by AIRBUS and the CAAC Date of the module A project supported by AIRBUS and the CAAC Date of the module 2 - Climb in operation Example: A320 climb at constant speed 250 kt (ATC limitation) climb at constant speed A320 : 300 kt climb at constant Mach A320 : M 0.78 Top Of Climb (TOC) Start of climb 10000 ft 29500 ft acceleration Change over altitude A project supported by AIRBUS and the CAAC Date of the module 2 - Climb in operation Energy conservation Three sources of energy are available to generate aerodynamic forces : - kinetic energy, which increases with increasing speed - potential energy, which is proportional to altitude - chemical energy, from the fuel A project supported by AIRBUS and the CAAC Date of the module altitude True Air Speed Rate of Climb constant CAS constant Mach constant Mach TROPOPAUSE climb at constant TAS 2 - Climb in operation Energy conservation A project supported by AIRBUS and the CAAC Date of the module maximum air climb gradient climb at RC max minimum consumptiondistance climb high speed climb Cruise FL MAXI CLIMB THRUST CRUISE THRUST distance 2 - Climb in operation A project supported by AIRBUS and the CAAC Date of the module Climb at Maximum Rate Climbing at the maximum rate of climb speed enables a given altitude to bereached in the shortest time. Climb at Maximum Gradient The climb gradient at green dot speed is at its maximum. Climbing at green dot speed enables a given altitude to be achieved over the shortest distance. Climb at Minimum Cost Minimum Cost Between CI=0 and CImax CI=0=IASECON=maximum rate of climb speed CI=CImax=IASECON=VMO-10kt A project supported by AIRBUS and the CAAC Date of the module Influencing Parameters 1. Altitude Effect PA↑ ⇒ climb gradient ↓ rate of climb ↓ 2. Temperature Effect Temperature ↑ ⇒ climb gradient ↓ rate of climb↓ 3. Weight Effect Weight ↑ ⇒ climb gradient ↑ rate of climb ↑ A project supported by AIRBUS and the CAAC Date of the module Influencing Parameters 4. Wind Effect Headwind ↑ ⇒ Rate of climb Fuel and time to T/C → Flight path angle (γg) ↑ Ground distance to T/C↓ Tailwind↑ ⇒ Rate of climb → Fuel and time to T/C→ Flight path angle (γg) ↑ Ground distance to T/C ↑ A project supported by AIRBUS and the CAAC Date of the module 1 - Climb angle and rate of climb 2 - Climb in operation 3 - Cabin climb Table of Contents A project supported by AIRBUS and the CAAC Date of the module aircraft cabin time cabin rate of climb 500 ft/mn pressure Zp Zp > 30000 ft Zp = 8000 ft 3 - Cabin climb A project supported by AIRBUS and the CAAC Date of the module Table of Contents 1 - Cruise 2 - Climb 3 - Descent 4 - Holding A project supported by AIRBUS and the CAAC Date of the module 1 - Descent angle and rate of descent 2 - Descent in operation 3 - Cabin descent Table of Contents A project supported by AIRBUS and the CAAC Date of the module 1 - Descent angle and rate of descent 2 - Descent in operation 3 - Cabin descent Table of Contents A project supported by AIRBUS and the CAAC Date of the module TAS rate of climb rate of descent TASRDmin TASmin minimum rate of descent maximum rate of descent Given engine thrust, m speed limit VMO / MMO 1 - Descent angle and rate of descent A project supported by AIRBUS and the CAAC Date of the module True Air Speed rate of descent min speed limit VMO / MMO light gross weight heavy gross weight 1 - Descent angle and rate of descent Influence of weight RD when w A project supported by AIRBUS and the CAAC Date of the module air angle of descent ground angle of descent flight path TAS HEADWIND 1 - Descent angle and rate of descent A project supported by AIRBUS and the CAAC Date of the module no wind FL 350 102 NM tailwind 20 kt 108 NM headwind 20 kt 96 NM 1 - Descent angle and rate of descent A 320 A project supported by AIRBUS and the CAAC Date of the module 1 - Descent angle and rate of descent 2 - Descent in operation 3 - Cabin descent Table of Contents A project supported by AIRBUS and the CAAC Date of the module V.3.3.2 - Descent in operation Example: A320 landing descent at constant speed A320: 300 kt (CAS) descent at constant speed 250 kt (ATC limitation) descent at constant Mach A320 : M 0.78 deceleration deceleration to approach speed 10000 ft 29500 ft Top Of Descent (TOD) .78/300/250 A project supported by AIRBUS and the CAAC Date of the module altitude True Air Speed Rate of Descent constant CAS constant Mach constant Mach TROPOPAUSE V.3.3.2 - Descent in operation Energy conservation A project supported by AIRBUS and the CAAC Date of the module cruise thrust descent at idle thrust high speed low speed 2 - Descent in operation Emergency descent : - Idle - MMO/VMO - Spoilers A project supported by AIRBUS and the CAAC Date of the module 2 - Descent in operation Influencing Parameters 1. Altitude Effect it is difficult to assess descent parameters (gradient and rate), as they only depend on drag and not on thrust (which is assumed to be set to idle). 2. Temperature Effect As for pressure altitude, the temperature effect is difficult to assess. Indeed, 3. Weight Effect Weight↑ ⇒ descent gradient↓ rate of descent ↓ A project supported by AIRBUS and the CAAC Date of the module 2 - Descent in operation 4. Wind Effect Headwind ↑ ⇒ Rate of descent → Fuel and time from T/D → Flight path angle ∣γg∣↑ Ground distance from T/D ↓ A project supported by AIRBUS and the CAAC Date of the module 1 - Descent angle and rate of descent 2 - Descent in operation 3 - Cabin descent Table of Contents A project supported by AIRBUS and the CAAC Date of the module emergency descent cruise time Zp A320 maximum altitude complying with max envelope of allowed descents max normal cabin rate of descent 300 ft/min 3 - Cabin descent A project supported by AIRBUS and the CAAC Date of the module Table of Contents 1 - Cruise 2 - Climb 3 - Descent 4 - Holding A project supported by AIRBUS and the CAAC Date of the module 1 - Holding speed 2 - Optimum holding altitude Table of Contents A project supported by AIRBUS and the CAAC Date of the module 1 - Holding speed 2 - Optimum holding altitude Table of Contents A project supported by AIRBUS and the CAAC Date of the module 1 - Holding speed Holding minimize the fuel flow (FF) FF = TSFC x Thrust Minimize thrust Minimum drag or maximum L/D ratio T = Drag = mg L/D A project supported by AIRBUS and the CAAC Date of the module 1 - Holding speed D,T V Minimum thrust drag Given m, t°C, Zp, thrust lever L/D max V opti Airbus Vopti = GREEN DOT A project supported by AIRBUS and the CAAC Date of the module 1 - Holding speed 2 - Optimum holding altitude Table of Contents A project supported by AIRBUS and the CAAC Date of the module Zp FF Given m minimum fuel hour consumption per altitude Optimum holding 2 - Optimum holding altitude Minimum Drag Speed A project supported by AIRBUS and the CAAC Date of the module Zp FF decreasing weight optimum holding altitude 2 - Optimum holding altitude Minimum Drag Speed A project supported by AIRBUS and the CAAC Date of the module At the end of the flight, the optimum altitude is often too high (low weight) In Operations, holding is made at the assigned altitude (ATC) at the minimum drag speed corresponding to the weight A project supported by AIRBUS and the CAAC Date of the module SR Mach Zp Zp1 Zp4 Zp5 Zp3 Zp2 A project supported by AIRBUS and the CAAC Date of the module SR Mach Zp Zp1 Zp4 Zp5 Zp3 Zp2 A project supported by AIRBUS and the CAAC Date of the module SR Mach Zp Fixed Mach nb Zp4 = Optimum altitude to fly at this Mach nb (best SR for the chosen Mach nb)作者: 忙盲忙 时间: 2010-7-28 08:58:39 标题: 楼主辛苦啦！
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