Fuel Conservation Strategies Cruise Flight

CRuiSE FLigHT  iS THE pHASE  OF FLigHT  BETWEEN CLiMB   AND DESCENT.

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  Aero quArterly

qtr_04 | 07

Fel Conservaton  Stratees:  cs Fh b W Roberson, Senor Sfet Pot, Fgt Opertons; Robert Root, Fgt Opertons Engneerng; nd De ads, Fgt Opertons Engneer Ths artcle s the second n a seres exlorn el conservaton stratees.

A    c f c    c  c  v  cm m, m, b c   m     . A    b,    cm,  m vm    f. ths a ds s fh, pss vas

Cruise light deined

s shs, ad s h s  wd  s spd aas. i as dssss h ashp w s fh ad s dx

cs fh s h phas  fh ha as w  ad ds. th as pas 

(ci) whh was dsssd  h s a  hs ss, “F csva Sas: cs idx expad”  h sd-a 2007 AERO  2007  AERO .

p  ad p  a sd pa  hs phas  fh. As a asd, apad w ad av, whh as pas p 

usd apppa, h ci a  h fh aa p (Fmc) a hp as sa d pa ss. Hwv,

ad  sa, a   avdd hh apppa s pa. th vaas ha a h a  ad 

a pas d’ ak  advaa  hs pw .

 a spd s, ad s, ad,  s d,   av (cg). ths a ss  spd s.

 A   hh-v jvs a f spd s. ths jvs, whh dpd  h pspv  h p, dspah, pa ,  pas pa, a  pd  v as: 1. max h dsa avd  a v a   (.., ax a). 2. m h  sd  a v dsa vd (..,  p ). 3. m a p  (..,  ). 4. m a pa s  h p (..,  s,   [econ] spd). 5. maa h fh shd. th s w jvs a ssa h sa as  h ass h apa w  fw  ahv p  a.

WWW.boeing.com/commerciAl/AeromAgAzine

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P   c    -m   m  q m  m b  c    m m   f.

Considerations aeCting Cruise strategies

h spd ha w pvd h hs dsa avd  a v a   d ad h   d  a v s dsa.

i add    h va sa jvs

lrc has  hsa dd as h spd av mrc ha w s  a 1 p das   a  s  aa s p

sd av  s fh, ps a  d  da wh sh  sas ha a  h  pa aad h s sa    s d a fh. ths sas a d: ■

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F a xd spd ha s pa wh h a  a spd  s. F a spd aad  ahv a

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d   ava (.., rtA) a a x. F a spd aad  ahv   fw wh hd

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(.., ax da). Wh dd  aa a sp spd  a a .

possiBle Cruise sCheMes th a w ha spd ss  h s phas  fh. th ada spd s -a s (lrc). lrc spd s ad wh ax-a s (mrc) spd, whh s

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CI=

ka  pd   d. th ass x,  Aero dynamcs dynamcs or Naval Avators , vsd  1965, sas: “ms -a s pa s dd a h fh d whh pvds 99 p  h as ax sp a. th advaa s ha 1 p  a s add  3  5 p hh s v. S hh s spd has a a   advaas, h sa sa  a s a a

Tm c ~ $/ F c ~ c/b

aa.” ths p s apha sad   1. bas  s  h  d s assad wh a fh, a h   h spd  s a pa s econ spd, asd  h d ci. ths spd, whh ds s ads w p  ad p , s asd  a sa  h -ad pa xpss ha a sp  ah a’s pa. ci s dd as h a  dpd ss   ss.

long-range Cruise and Cost index th ashp w lrc spd ad econ spd s d  ah b apa d.  As sad, lrc s asd  a 1 p pa   a, wh h econ spd ss ci as a p ha s asd  a  dad a  aa ss. Hwv,  s pss  dv a ci  a s ds ha appxas

  Aero quArterly

qtr_04 | 07

REPRESENTaTiVE COmPaRiSON OF mRC  aND lRC

Fre 1 Modern fht manaement  systems atomatcally adjst  LRC seed throhot crse  or weht chane de to  el brn, as well as chanes  n crse alttde.

68

MRC: Mach .826  67

LRC: Mach .840  1% Penalty 

   )     g    k    0    0    0  ,    1     /    m    n    (    e     g    A    e    l    i    m    l    e    u    F

66

65

64

63

62

0.76

0.77

0.78

0.79

0.80

0.81

0.82

0.83

MRC

0.84

0.85

0.86

LRC

cruiSe mAcH number

WWW.boeing.com/commerciAl/AeromAgAzine

25

lrc  s  h s spd ha ss. F 2 shws h appxa ashp  b a apas. i s v pa   ha h lrc spd s as vsa hh ha h spd ha w s  s h ci sd  s as. i ad wh a w  sa a dsa, a ps w p  f lrc spd hk ha  w v h h s s  h a . As shw   2, h s sa  sv  s  s a v w s dx, wh  pvd h ax a. A p a as dsa hs d s fh  p d cis  h Fmc ad pa wh lrc  sv h pdd  a dsa.

eeCts o wind on Cruise speed i add   aa p ss, h s  h   f econ sad  lrc wh s b apas. th lrc spd

F xap,  h ps  a s awd, h econ spd w  dd  d  ax h advaa ad  h awd d h s. cvs, h econ spd w  asd wh f  a hadwd  s   h pa assad wh h hadwd (s xap  . 3).

the relationship Between operating Costs and Cost index i  ps as av  h ss, a spd d  ci w aa h s a pa  h apa. i,

suMMary i d  fh ws  ahv p s pa,  s ssa  s dsad h fh’s sa jvs, ad h  s h s spd ha s s hs jvs. i s a pa   ha a-wd sas a s  h d  dvas  h vd sa. Apppa s vas wh ah a, ad ss v  ah fh. b Fh opas e assss as’ fh pas dpas  p a aa ci ha w a h   ss  h s. F  a, pas a Fhops.e@..

hwv, a a xps s h ss, a as  ci w a h s a pa. i h as, h ha ci w s  has  h s spd aad  h Fmc. ev aa a s dx asd  appxa  ss ad f econ spd

aad  h Fmc s pa  adjsd  wds a s ad  h econ spd s. As

a d sa s s  h a. t  sd s v, ci shd  asd  a phsv vaa  a pa’s

a s, lrc s da    wd ds, wh h econ spd s pd  a s wd ds.

sp pa ss. F hs as, fh ws pa v a dd ci va  h fh pas dpa, ad  s a  advsa  dva  hs va ss sp sh- sas dad .

26

  Aero quArterly

qtr_04 | 07

RElaTiONShiP OF COST iNDEX TO lRC FOR BOEiNG  aiRPlaNES

Fre 2  The LRC-eqvalent cost ndex  vares or derent arlane  models and ennes.

tpa a ci vas

mrc

  m

lrc

(c m  km)

H c mc mb

E  I (I) aiRPlaNE mODEl

TyPiCal aiRliNE Ci ValUES

 aPPROXimaTE lRC EqUiValENT

71 7

0

40  60

70

737-3/4/500

0

5   25

25

737-6/7/800

0

10  30

35

7 57

0

1 5   50

85

767

0

1 5   55

70

777

0

9 0   1 50

180

mD-11

0

80  120

200

7 4 7 -4 0 0

0

25  80

230

ECON SPEED iS OPTimiZED FOR CRUiSE WiND CONDiTiONS

Fre 3 

mRC

EON  c COST iNDEX

100 kT TailWiND

ZERO WiND

100 kT hEaDWiND

0

0 . 77 3 *

0.773

0.785

80

0 . 78 7

0.796

0.803

max**

0 . 8 11

0.811

0.811

*Fmc w  sw dw w s a ci=0 econ spd. **A ax ci, Fmc w f a vp   a wd ds.

WWW.boeing.com/commerciAl/AeromAgAzine

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