Delayed Flap Pocedure 727

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NASA CR-137907

APPLICATION O F N A S A - A R CD E L A Y E D F L A P A P P R O A C H P R O C E D U R E ST O B O E I N G 727 AIRPLANE

ROBERT L. ALLISON

February 1977

FINAL REPORT

Prepared under contract NAS2-8953Boeing Commercial Airplane Company

P . O . Box 3707Seattle, Washington 98124

Distribution of this report is provided in theinterest of information exchange. Responsibilityfor the contents resides in the author or organizationthat prepared it.

NASANATIONAL AERONAUTICS ANDS P A C E ADMINISTRATION

Ames Research CenterMoffitt Field, California

R E P R O D U C E D B YNATIONAL T E C H N I C A LINFORMATION S E R V I C EU . D E P A R T M E N T O F C O M M E R C ES P R I N G F I E L D , V A . 22161

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1. Report No. 2. Government Accession No.N A S A C R - 1 3 7 9 0 74. Title and SubtitleApplication of N A S A - A R C Delayed Flap Approach Proceduresto Boeing 7 2 7 Airplane

7 . Author(s)R o b e r t L. Allison9. Performing Organization N a m e and AddressBoeing C o m m e r c i a l Airplane CompanyP . O . Bo x 3 7 0 7Seat t le . Was hing to n 9 8 1 2 4

1 2 . Sponsoring Agency Name and A d d r e s sA m es Res ear c h Cent erNational A e r o n a u t i c s an d Space AdministrationMoffett Field. California 9 4 0 3 5

3. Recipient's Catalog No.

5. Report DateFebruary 1 9 7 7

6. Performing Organization Code

8. Performing Organization Report No.D6-443 80

10. W o r k Unit No.

1 1 . Contract or Grant No.N A S 2 - 8 9 5 3

13 . Type of Report and Period CoveredFinal Report

1 4. Sponsoring Agency Code

1 5. Supplementary Notes N A S A T e c h n i c a l M o n i t o r :B o e i n g P r o g r a m M a n a g e r :

D r . J o h n S . B u l lG u i d a n c e a n d N a v i g a t i o n D i v i s i o nJ o h n P . H e a d l a n d7 0 7 / 7 2 7 / 7 3 7 Fl i i ih t C o n t ro l s T ech n o l o gy

1 6. A b s t r a c tT h i s r ep o r t p r e s en t s th e r e s u l t s of an en g i n ee r i n g a n d p i lo te d s i m u l a t o r s t u d y to a d a p t a N A S A -d e v e l o p e d - a p p r o a c h e n e r g y m a n a g e m e n t s y st e m ( A E M S ) c o n c ep t t o t he B 7 2 7 . T h e A E M S c o n -c e p t w a s d e v e l o p e d a n d f l i gh t t es ted o n a CV-990 b y t he A m e s R e s e a r c h C e n t e r ( A R C ) . T h ep u r p o s e o f t h e A E M S i s t o r e d u c e a p p r o a c h t i m e , f ue l , a n d n o i s e b y p r o v i d i n g c o m p u t e r - d r i v e nco ck pi t d i sp la ys to ass i s t the p i lo t in f l y i n g o p t i m i z e d d e l a y e d f lap a p p r o a c h ( D F A ) p r o ce d u r e s .T h e B o e i n g s t u d y , r e p o r t e d h e r e i n , i n c l u d e s d e v e l o p m e n t o f t h e D F A f l i gh t p r o f il e s , t h e A E M Sa i r b o r n e d i g i t a l c o m p u t e r a l g o r i t h m , a n d as s o c i a t ed co ck p i t d i s p l ay s . S t ud y g ro un d r u l e s a n dp e r t i n e n t a e r o d y n a m i c a n d n o i s e t r e n d d a t a u s e d i n d e v e l o p i n g t h e f l ight p ro f i l e s a r e p re s en t ed .A p p r o a c h t i m e , f u e l , a n d noise f o r t he DF A a r e co m p ared to s ev e ra l o t h e r t y p es o f p r o c e d u r e s .T h e t h e o r y a n d o p era t i o n of t he A E M S , a n d co m p a t i b i l i t y wi t h ex i s t i n g s y s t em s a re d i s cu s s ed .R e s u l t s o f t h e p i l o te d s i m u l a t o r s tu d i e s , i n c l u d i n g r e c o rd e d d a t a f o r a p p r o a c h e s f l o w n w i t ha u t o p i l o t a n d w i t h m a n u a l c o n t r o l a r e p r e s e n t e d .D e t a i l e d d e f i n i t i o n of t he A E M S h a r d w a r e a n d c o m p u t e r s o f t w a r e r e q u i r e m e n t s a r e p res en t eds e p a r a t e l y i n t h e p re l i m i n a ry av i o n i c s p ec i f i ca t i o n , N A SA C R - 1 3 7 9 0 6 . E s t im a t e d i m p l e m e n t a t i o ncos t s a re p res en t ed in N A S A C R - 1 5 1 94 2 .

1 7 . Key W o r d s (Suggested by Authors) )delayed flap approac henergy managementfuel c ons ervat ionnoise abat em entoperational procedures

19. Security Classi f . (of this report)Unclassified

18. Distribution Statement

Unlimited

20. Security Classif. (of this page) 21. No. of Pages 22. Price"

"For sale by the National Technical Information Service, Springfield, Virginia 2 2 1 5 1


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C O N T E N T S

1.0 S U M M A R Y 12.0 I N T R O D U C T I O N 33 .0 S Y M B O L S A N D A B B R E V I A T I O N S 54.0 C O N C E P T 94 .1 Ov erv iew 94 .2 E q u i p m e n t 104 .3 C o m p u t e r A l g o r i th m 14

4.4 Op era t io n 194 .5 Ty p ica l A p p ro ach es 2 2 .5.0 B E N E F I T S 265.1 Pro cedu res D ef in i t io n s 2 85 .2 C o m p u t e d T i m e a n d Fu e l C o mp ar i so n s 3 05 .3 C o m p u t e d N o i s e D a t a 3 5

5.4 Simu la to r C o mp ar i so n s 436.0 D E V E L O P M E N T 47

6.1 Criteria 476.2 Fl ight Prof i les 476.3 C o m p u t e r A l g o r i t h m 636.4 Simu la t io n 70

7.0 E V A L U A T I O N 747.1 Pi lo t Ev alu a t ion 747 .2 Displays 787.3 Sy s tems C o mp a t ib i l i t y 807 .4 P e r f o r m a n c e and S a f e t y 857.5 A b u s e s and Fai lu res 94

8.0 C O N C L U S I O N S AND R E C O M M E N D A T I O N S 989.0 R E F E R E N C E S 100

P r e c e d i n g p a g e b l a n k


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A PPLI C A TI ON O F N A S A - A R CD E L A Y E D F L A P A P P R O A C H P R O C E D U R E ST O B O E I N G 7 2 7 A I R P L A N ER o b e r t L . A l l i s o n

B o e i n g C o m m e r c i a l A i r p l a n e C o m p a n y

1.0 S U M M A R YB o e i n g h as b e e n p a r t i c i p a t i n g in a N A S A A m e s R e s e a rc h C e n t e r ( A R C ) p r og r am to dev e lo pan a p p r o a c h e n e r g y m a n a g e m e n t s y s t e m (A E M S ) c o n c e p t a n d asso c ia t ed de lay ed f lapa p p r o a c h ( D F A ) p r o c e d u r e s fo r the B o e in g 7 2 7 . T h e p u r p o s e of the p r o c e d u r e s is to r e d u c ea p p r o a c h t i m e , f u e l , a n d c o m m u n i t y n oi se d u r i n g r o u t i n e ai r l ine o p e r a t i o n . T h e A E M S co n -sists o f a n a i r b o r n e d ig i ta l c o m p u t e r a n d c o c k p i t d i s p l a y s t h a t i n d i c a t e w h e n to m a n u a l l yse t the f laps , gea r , an d th ro t t l e s to fo l lo w th e des i red D F A p ro f i l e . C o n f ig u r a t io n ma n age -m e n t r a th e r th an th ro t t l e m o d u la t io n i s u sed to co n t ro l sp eed du r in g th e dece le r a t io n p h ase .A D M E g r o u n d station co l lo ca ted w i th th e V A S I or ILS glide slope is r eq u i r ed .T h e A E M S c o n c ep t w a s d e v e l o p e d a n d f l igh t t e s t ed by th e A R C o n a CV-990. The objec-t i ves of the B o e i n g s t u d y w e r e to a d a p t th e N A S A c o n c e p t to the 7 2 7 ; to p r o v i d e d a t ar e g a r d ing t h e t i m e , f ue l , an d n o i se be n e f i t s ; t o a ssess sy s tems c o m p a t ib i l i t y an d a i r c r eww o r k l o a d ; and to p rep a re a prel iminary av ionic specif ica t ion . N o h a r d w a r e d e v e l o p m e n t o rf l igh t t e s t in g w ere in v o lv ed .F l igh t p ro f i le s w ere dev e lo p ed th a t p ro v ide su b s t an t i a l ben e f i t s w i th r easo n ab le in i ti a lap p ro ach sp eeds a n d w i t h m i n i m u m p i t c h a t t i t u d e v a r i a t i o n s d u r i n g th e decelera t ion . T h eprefer red 7 2 7 D F A f l igh t prof i le fo r n o n ic in g co n d i tio n s beg in s in a c lean co n f igu r a t io n a t2 2 0 kn . Ho w ev er , f l aps 2 an d r edu ced sp eeds can be u sed w i th l i t t l e r edu c t io n in ben e f i t s ,an d th e A E M S w i l l a d j u s t to any in i t ia l f l ap / speed c o m b i n a t i o n t h a t m i g h t b e r eq u i r ed inth e o p era t io n a l en v i ro n men t . Th ru s t is r e d u c e d to n ea r i d l e a t a p o i n t d e t e r m i n e d by theA E M S . F lap s , gea r , an d th r u s t a r e seq u en ced a s in d ica ted by th e d i sp lay s to s t ab i li ze a t atarget a l t i tude se lec ted by the pi lo t . T h e A E M S c o m p e n s a t e s fo r w i n d a n d other o p era t io n a lv a r i ab le s to consis ten t ly h i t the t a rge t. M in im u m s t ab i li za t io n h e igh ts of 152 m (500 ft) forV F R conditions and 305 m (1000 f t ) for IFR conditions a re considered realistic.A p p r o a c h t i m e , f u e l , an d n o i se w ere co mp u ted fo r several types of p ro cedu res in still air,h e a d w i n d , a n d t a i lw in d co n d i t io n s . R e la t i v e to cu r r en t A T A air l ine procedures , t h e D F Aprocedure fo r still air, VF R co n d i t io n s r edu ces ap p ro ach t ime b y 2 m i n , f u e l b y 1420 N(320 Ib) or more, and centerline noise (prior to the stabi l iza t ion poin t ) by 10 E P N d Bu n t r ea ted n ace l l e s , 6 E P N d B fo r quie t nacel les . T h e r e d u c t i o n in the 90 E P N d B g r o u n d -level-noise contour is co mp arab le to that prov ided b y quie t nacel les .


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W i t h t h e 15 2 -m (5 0 0 - f t ) s t ab i l iza t io n a l t i t u de , p i lo t co m m en t s in d ica te th e w o rk lo ad i sh i g h e r t h a n f o r c u r r e n t I L S p r o c e d u r e s b u t r e a s o n a b l e , be i n g co mp arab le to an I FR n o n -

"precis ion approa ch ." G l ide s lope "and speed c 'o ri t rpTwere acc epta ble , and the land ing check-list w a s c o m p l e t e d a b o v e 1 5 2 m (5 0 0 f t ) .T h e p r o c e d u r e s are co mp a t ib l e w i th cu r r en t sy s t ems . N o m o d i f i c a t i o n s w o u l d b e r eq u i r ed tot h e cu r r en t au to p i lo t o r f l igh t direc tor , except for inst a l la t ion of a fast /s low ind icator .C u r r e n t a u t o p i l o t t r i m m o t o r r a t e s a r e adeq u a te . C o m p a t ib i l i t y w i t h ic in g co n d i t io n s i s p ro -v ided by a u to m a t i ca l ly se l ec t in g a l t e rn a te f l i gh t p ro fi l e s u s in g h igh e r p o w er se tt i ngs(N j > 5 5 %) w h en th e in l e t A N TI - I C E sw i t ch i s ac t i v a t ed . Th e p ro f i l e co m p en sa te s fo r w in dv e lo c i ty ( co mp u ted o n bo a rd u s in g D M E gro u n d sp eed ) so t h e r e n eed be no o p era t io n a lr e s t r i c t io n s o n u sage in t a i lw in ds .A s s u m i n g t h e r e q u i r e d D M E g ro u n d s t a t i o n s wil l b e i n s t a l l ed , t h e A EM S co n cep t ap p ea r sp r ac t i ca l fo r appl ica t ion to the 7 2 7 . H o w e v e r , n o co n c lu s io n s can be d r a w n b y B o e in gr e g a r d ing accep tab i l i t y to a i r l in es fo r ro u t in e o p e ra t io n a l u se . T h e d a t a p r o v i d e d b y th iss t u d y can be used to assess th e ben e f i t s and to ob t a in a p re l imin a ry e s t ima te of the possibleimp ac t o n p i lo t w o rk lo ad an d a i r t ra f f ic contro l (ATC) proce du res . Cost es t im ates for theav io n ic s an d gro u n d f ac i l i t i e s a re repor ted separa te ly .I f f u r th e r dev e lo p men t of the concept a ppears w arra n te d , c lose coord inat ion wi th ATC, th eF A A , a n d t h e a i r li n e s , i n c l u d i n g s i m u l a t o r e v a l u a t i o n s b y airl ine pi lo ts ear ly in the program,is r e c o m m e n d e d . T h e algor i thm should b e m o d i f i e d to i n co rp o ra te n o n s tan da rd d ay provi-s ions a n d o t h e r i m p r o v e m e n t s n o t i n c l u d e d in th i s co n cep tu a l s t u dy . A co mp le te de ta i l eddes ign cy c le w i th a i r l i n e an d av io n ic s v en do r p a r t i c ip a t io n w o u ld be r eq u i r ed p r io r to bu i ld -in g f l i gh t h a rdw a re . A l t e rn a t i v e me ch an iza t io n ap p ro ach es , an d sa fe ty a sp ec t s su ch a s th eneed fo r r e d u n d a n c y , f a i lu r e d e t e c ti o n , o r independent speed moni tor ing shou ld b e p u r s u e da t t h a t t ime .


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2.0 INTRODUCTIONN A S A - A R C i s inv es t iga t ing the a pp l ic a t ion o f an A E M S concep t to j e t t r anspor t a i r c ra f t ino rder to inc rease the fue l c o n s e r v a t i o n a n d n o i s e a b a t e m e n t b e n e f i t s a t t a i n a b l e f r o m D F Aprocedu res . T he r esu l t an t p roced u res a re s im i la r , in p r inc ip le , to the Ai r T ranspo r t Associa-t ion (AT A) no ise aba te m e nt approach p rocedu res descr ibed by r e fe rence 1 . T he A T A proce-d u r e s sugges t r em ain ing in a c l e a n c o n f i g u r a t i o n as long as poss ible , delaying f ina l l a n d i n gf lap ex tens ion u n t i l abo u t 305 m (1 000 f t ) above field elevat ion, u s ing the low est permis-sible l a n d i n g f lap se t t ing , an d s tab i l i z ing th e f inal a p p r o a c h at no t less than 152 m (500 ft)a b o v e field e l e v a t i o n . B y p r o v i d i n g p r ec i si o n e n e r g y m a n a g e m e n t g u i d a n c e , i n c l u d i n g c o m -pensa t ion fo r winds , the AE M S a l lows m ore o f the approach to be f lown in a low d ragco n f igu r a t io n whi le s t i l l a l lowing s tab i l i za t ion above 152 m (500 f t ) . T h e A E M S c o n c e p tw as d e v e l o p e d by A R C fo r th e NAS A CV-990 research a i rp lane (a s descr ibed in r e f . 2) andh as been fl ight d e m o n s t r a t e d to a n u m b e r o f a i r l ine an d indus t ry p i lo t s .

T h e p u r p o s e o f t h is N A S A / B o e i n g s t u d y is to d e t e r m i n e a p p l i c a b i l i t y of the CV-990 con-cep t to the 72 7 fo r pos s ib le in t rod u c t io n in to ro u t ine a i r l ine s e rv ice . S pec i f i c s t ud y ob jec-t ives were to : D e v e l o p fl ight p r o f il e s , a i r b o rn e c o m p u t e r a l g o r i t h m , a n d cockp i t d i sp lay concep ts fo rthe 727 us ing the NA S A CV-990 A E M S as a base l ine D e t e r m i n e the t i m e , f u e l , and no ise ben ef i t s E v a l u a t e s y s t e m s c o m p a t i b i l i t y and Boeing p i lo t accep tance cons ider ing per fo rm ance ,c r e w w o r k l o a d , an d sa fe ty Prov ide a pre l im inary av ion ic spec i f i ca t ionThe contra ct tasks are ou t l ine d in table 1 . The w ork cons is ted of engineer ing analyse s andf ixed-base s imulator s tudies with cons iderat ion l imited to nom inal 727-2 00/JT8D -9 charac-teristics ( i .e. , n o sys tem tolerances) fo r s tandard days on ly . A l though th i s Boe ing s tudyprogram did no t i n c l u d e f l ight tes t ing, prel iminary qual i ta t ive checks of the f l ight prof i leswere ob ta ined on a no-cost, non interferen ce basis du r ing other schedu led tes t f l ights .Because th is was a very aus tere program a feas ibi l i ty s tudy approach w as a d o p t e d . T hein ten t was t o prov ide the scoping level information needed to de te rm ine whether f u r ther ,m o r e detailed deve lopm ent is war ran ted . A l though there are a n u m b e r of ways to imple-m e n t th e A E M S concept on the 727 , t im e an d budget cons traints required t h a t only one beselected fo r s t u d y . T h e selected concept w as im plem ented on the s im u la to r an d deve lopedonly to the extent necessary to provide a representat ive working sys tem sui table fo r eva lua t -in g flight profiles, pi lot work load , f u e l /no i se ben ef i t s, and sys tems com patibi l i ty (au topi lo t ,etc . ) . There w a s n o t im e to inves t igate a l t e rna te concepts , to resolve detailed design ques-t ions , or to fu l ly develop th e computer logic necessary to cope with a ll s i tuat ions t h a t m igh toccur dur ing operational use.


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Table J.-Contract Tasks

1.

2.3.

4.

5.

Develop 727 Engineering simulation at Boeing Complete six OOF low-speed model, flaps 0- Pitch and roll flight director/autopilot Engine dynamics and fuel flow Centerline noiseuntreated and QN

30

Validate simulation against flight data

Develop flight profiles andcomputer algorithm Criteria Trend data (attitude/drag/noise) and computed profiles FCT minicomputer (NOVA) development of algorithm Simulator-EAI-8400andVARIAN

Engineeringand pilot evaluation Definition ofcurrent procedures Fuel/noise comparisons Hardware implementation concept Simulationsafety, workload, FD/AP compatibility

Specification Computer Dsplays

A major i ty of the contract t ime and effor t went in to the deve lopment phase , first todevelop the basic a i rplane simulat ion and the A E M S algor i thm concept , and then to imple-m e n t an d fur ther develop the algorithm on the s imu la to r . Consequen t ly , th e e v a l u a t i o nphase was qu i te l imi ted and w as or iented toward assu r ing that there were no major problemareas of a concep tua l na t u r e r a the r tha n e valu at ing hardw are design detai ls . Heav y rel iancewas placed on pilot and eng ineer ing jud gm ent .T he prel iminary AEMS avionic specif icat ion def ines a baseline system for use in obtainingprel iminary est imates of hardware implementat ion costs, and serves as a reference forf u r t he r discussion and development. I t should not, however , be interpreted as a final pro-duction specification for air l ine retrofit . A complete detailed design and evaluation cycle ,involving th e airlines and the avionic v e ndor , would be required before releasing such aspecif icat ion.


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3.0 S Y M B O L S AND A B B R E V I A T I O N SA D IA E M SA F C SA G LA L P AA PA PPA R BA R CA R I N CA T AA TCA T RA VGC A D CC De.g.C LDdegD F AD M ED O FdotdVG/dtdVG/dxEAI-8400E P N d BE P N LE P RF A AF A R

a t t i t u d e d i r e c t o r i n d i c a t o ra p p r o a c h e n e r g y m a n a g e m e n t s y s te ma u t o m a t i c f light control sys temabove g round levelAi r l i ne Pilot ' s Associat iona u t o p i l o tapproachA ir Regis t r a t ion BoardAm es Research Cen te rA e r o n a u t i c a l R a d i o , I n c o r p o r a te d ( e l ec t r o n ic e q u i p m e n t s ta n d a r d s )A ir Transpor t Associat ionair t raff i c conrolA u s t i n T r u m b u l l R a d i o ( A R I N C d e s i g n a ti o n fo r electronic case sizes p erA R I N C s p ec 4 0 4 A )averagecen t ra l a i r da ta com pu te rdrag coeff icientcen te r of gravi tylift coeff icientd ragdegreede layed f lap approachd i s ta n c e m e a s u r in g e q u i p m e n tdegrees of f r eedomG S E index m ark o n A D Ide r i va t i ve o f groundspeed wi th r espec t to t im e ( long i tud ina l acce le ra t ion)der iva t ive of groundspeed wi th respect to dis tancecom pu te r u sed fo r piloted s imulat ionef fec t ive perceived noise, decibelsef fec t ive perceived noise levelengine pressure rat ioFedera l Av ia t ion Adm in is t r a t ionFedera l A ir Regulat ion


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F C T Bo eing Fl ight Controls Technology S taffF D / A P F l ig h t D i r e c t o r / A u t o p i l o tFn net t h r u s tF O R T R A N c o m p u t e r l an g u a g eF S A A f l igh t s i m u l a t o r fo r a d v a n c e d a i r c r a ft (a t A R C )f t fee tg g r a v i t yG S glide s lopeG S E glid e s lope error ( a n g u l a r d i s p l a c e m e n t from G S )G W gross we igh t , l and in g g ros s weig h th a l t i t u d e a b o v e f ie ld e l e v a t i o nh j in i t i a l va lue o f a l t i t u d e u s e d in prof i l e pred ic t ionhmjn t a rg e t a l t i t u d e fo r s t a b i l i z i n g D F A1C in i t ia l c o n d i t i o n s for profi le c a l c u l a t i o n sIF R i n s t r u m e n t fl ight r u lesIL S i n s t r u m e n t l a n d i n g s ys te mINOP inopera t iveIP in i t i a l p o i n t t h e des i r ed po in t fo r genera t ing the f i r s t f lap c o m m a n dIPGS ini t ia l poin t gl ide s lopeK C A S kno ts , ca l ib ra ted a i r speedK E A S kno ts , equ iva len t a i r speedk n k n o t sKT A S kno ts , t r u e a i rspeedL liftIb p o u n d t h e U.S . eng ineer ing u n i t fo r weigh t an d forceL E lead ing edgem m e t e rm a x m a x i m u mm i n m i n i m u m , m i n u t eN n e w t o n t h e S I u n i t f o r f o rc e (Throughout this document, airplane and

f ue l weights (gravi ty forces) are expressed in N w h e r e 1 Ib = 4.448 N .)N A S A N a t i o n a l A e r o n a u t i cs and Space Adminis trat ionN A V A I D S n a v i g a ti o n a l a id snm i naut ical mileN O V A c o m p u t e r used fo r A E M S algorithm d e v e l o p m e n t


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NOMOPSQ Nref .rm sR N A VR T A CsstdVV A R I A NV A S lV F RVCAS

V f inalV(V 1C

VMOVplacardV re fVref30VTVw'w're fXX f ina lXICA 0A h7

72

engine compressor speed (lowpressure s tages)o u t e r m a r k e ro p e r a t i o n sq u i e t n ace l l ere fe renceroot m ean squarearea nav iga t ionN A S A Research an d T e c h n o lo g y A d v i s o ry C o u n c i lseconds tandardspeedm i n i c o m p u t e r u s e d fo r A E M S a l g o r it h m d e v e l o p m e n tvisual approach s lope indicatorv i sua l f l ight ru lesca l ib r a t ed airspeede q u i v a l e n t airspeedfinal approach speedg r o u n d s p e e din i t ia l v a l u e o f speed fo r prof i l e p red ic t ionm a x i m u m opera t ing speedflap p lacard speedr e f e r en ce approach speed(1 .3 V)V re f for naps 30t r u e airspeedrefe rence windspeed a t tower he igh tw i n d s p e e d ; var ies wi th a l t i t u dehor izon ta l d i s tance f rom touchdowntarget distance fo r s tab il i zing approach der ived wi th in th e c o m p u t e rfrom the p i lo t inpu t hminin i t ia l value of X for X - V prof i le predict ionpi t ch a t t i t ude var ia t iona t t i t ude dev ia t ion f rom G S u s e d in energy compe nsat ionflightpath angleglide slope anglef l ightpath angle pr ior t o GS cap tu re


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5 atmospher ic pressure ra t io6 p i t c h a t t i t u d e

~ u l o n g i t u d i n a l - t u r b u l e n c e rm s veloci tya v e r t ic a l t u r b u l e n c e rm s veloci ty


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4.0 C O N C E P T4.1 O V E R V I E W

T h e c o n c e p t o f u s i n g th e A E M S to assist th e p i l o t in f ly ing d e l a y e d f lap a p p r o a c h e s is out-l ined in f igure 1.

Energymanagementcomputer

Configuration controldisplaysin cockpit Low drag configuration Higher than normal speed

Delayed flap approach Conserves fuel Reduces noise

1 Stabilized atsafe altitude

Figure 1.-727AEMS Concept

4 .1 .1 PROCE DURET he in i ti a l approach i s flown in a low d rag conf igu ra t ion a t a speed co ns iderab ly h igher thanthe f ina l approach speed . A t the approp r ia te t im e , power i s r educ ed to idle1 and the f l apsa n d gear a re e x t e n d e d w h i l e d e c e l e r a t i n g to the f inal approach speed . T h e throttles a repar t i a l ly advanced to in i t i a te eng ine acce le ra t ion prior to select ing f inal approach f l aps andare fu r th er adv anced to norm al app roach pow er as the final approach speed is reached. T h ec o n f i g u r a t i o n and p ower changes a re s chedu led so as to s tab i l i ze in the l an d ing conf igu ra t iona t a t a r g e t a l t i t u d e a b o v e 1 52 m (500 ft), selected by the pilot. T h e r e m a i n d e r of theapproach i s conv en t iona l .


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4 .1 .2 PURPO S E OF THE A E M SP r o c e d u r e s o f t h i s t y p e c o u l d be_ f j p w n _ b y _ e x p e r i e n c e d p i l o t s u s i n g r u le -of - thum_b t e c h n i -q u e s t h a t w o u l d n o t r e q u i r e a d d i t i o n a l e q u i p m e n t . H o w e v e r , t h e ta r g e t a l t i t u d e f o r s t a b i-l i z ing t he a ppr oa c h wou ld ha ve t o b e h ig he r t o a l l ow a m a r g i n f o r e x p e c t e d d e v i a t i o n s .T h e s e d e v i a t i o n s w o u l d r e su l t from th e l ack o f pr e c i se r a ng e i n f o r m a t i o n in the c o c k p i t a n dfrom th e m a n y o p e r a t i o n a l v a r i a b l e s s u c h a s w i n d , w e i g h t, i n i t i a l a ppr oa c h spe e ds , g l i des lo p e ( G S ) c a p t u r e a l t i tu d e s , e t c . W i t h o u t e n er gy m a n a g e m e n t g u i d a n c e , i t w o u l d b e i m p r a c -t i c a l t o e x pe c t a p i lo t t o c on s i s t e n t l y h i t a ta r g e t a l t i t u de whi l e f o l l owin g a n op t imiz e dd e c e l e r a t i o n s c h e d u l e in an o p e r a t i o n a l e n v i r o n m e n t . T h e p u r p o s e of the A E M S is to pro-v i d e th e e q u i p m e n t n e e d e d to m a k e i t ope r a t i ona l l y p r a c t i c a l t o u s e o p t i m i z e d d e l ay e d f lapa p p r o a c h p r o c e d u r e s in rout ine a i r l ine se rvice .4 .1 .3 F U N C T I O N A L D E S C R I P T IO NT h e s y s te m e m p l o y s c o m p u t e r - d r i v e n c o c k p i t d i s p l a y s to assist th e p i l o t in f o l l o w i n g o p t i -m i z e d s p e e d s c h e d u l e s a nd i n c ons i s t e n t l y s t a b i l i z i ng a t a m i n i m u m t a r g e t a l t i t u d e . A na n n u n c i a t o r p a n e l i n d i c a t e s th e p r o p e r t i m e t o s e t t h r o t t le s , f laps , a nd g e a r , wh i l e a f a s t /s lo w i n d i c a t o r o n t h e a t t i t u d e d i r e c to r i n d i c a t o r ( A D I ) d i s p l a y s e n e r g y d e v i a t i o n s r e la t iv eto the des i red f l igh t pr of i l e . T h e a i rc rew se t the t h r o t t l e s an d e x t e n d f laps a n d g e a r ma n-u a l l y . T h e a i r p l a n e is c o n t ro l l e d i n t h e n o r m a l m a n n e r , e x c e p t c o n f i g u r a t i o n c h a n g e s r a t h e rt h a n throttle i n p u t s a re u s e d to m o d u l a t e e n e r g y d u r i n g th e de c e l e r a t i on pha se . T h e A E M Sis s t r ic t ly an a dv i so r y sys t e m whic h can be u s e d , i g n o r e d , o r t u r n e d off a t the d i sc r e t i on o fth e p i lo t .

4.2 E Q U I P M E N TT h e 7 2 7 A E M S r e s u l t in g f r o m t h i s s t u d y in c l u d e s th e f o l lo w i n g a v i o n ic c o m p o n e n t s , w h i c ha re d e f i n e d b y r e f e r e nc e 3 . D i g i t a l c o m p u t e r and i n t e r f a c e e q u i p m e n t Control pa ne l A n n u n c i a t o r p a n e lA fas t / s low i n d i c a t o r o n th e A D I i s use d as an e ne r g y m oni to r . Ins t a l la t i on of the avionicsr e q u i r e s a dd i t i ona l parts a n d w i r i n g w h i c h w o u l d be supp l i e d in an a i rplane re t rof i t k i t . Ina d d i t i o n to the a i r b o r n e e q u i p m e n t , o p e r a t i o n a l u se o f th e A E M S r e q u i re s a f l i g h tpa th r e f-erence ( I L S , V A S I , o r other) wi th collocated D M E g r o u n d station.Idle power was used for this feasibility study, which considered only standard day condi-

tions. An eng ine pressure ratio (EPR) setting slightly a b o v e idle would be used in an opera-tional system.

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4.2 .1 AVIONICSTh e AE M S a v ion i c c om po ne n t s a nd t he r e qu i r e d a i r p l a n e se nsor i np u t s a r e i nd i c a t e d sc he -mat ica l ly in f i g u r e 2 . Th e proposed locations for the c oc kp i t d i sp l a ys an d th e phys i c a la r r a n g e m e n t s of the c on t r o l pa ne l a n d a n n u n c i a t o r p a n el a re s h o w n in f i g u r e s 3 an d 4 . The sel o c a t i o n s an d a r r a n g e m e n t s a re a s d e f i n e d in the p r e l i m i n a r y a v i o n i c s p e c i fi c a t io n p r e p a re da s pa r t o f t h i s s t u dy . The f inal c on f ig u r a t i on f o r a n a i r l ine i ns t a l l a t i on c ou ld b e t a i lo r e d t om e e t i n d i v i d u a l a i r l in e r e q u i r e m e n t s . S i m u l a t i o n c o c k p i t d i s p l a y s u s e d d u r i n g d e la y e d f lappr oc e dur e s de ve lopme nt a r e de sc r ib e d i n s e c t i on 6.4.2.

Annunciatorpanel

Controlpanel

Fast/slowin ADI

o

Existing fast/slowcommands

Ship's power

Digitalcomputerandinterfaceequipment3/8-ATR-Jong

Throttle (No. 1) positiontransducer (new sensor)

Outboard flap positionLanding gear handle positionEngine anti-ice switch positionDME receiver Range Range rate Off flagCADC, airspeedAltimeter (barocorrectedaltitude)Cabin pressure controller(landing field elevationset)Flight director go-around modeselect

Figure 2.-727AEMS Schematic

1 1


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5IUjI

12


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E P R

8 . 8 8 8GEAR

FLAPS

INOPPUSH TO RESET

D OU Li

Annunciator Panel

Digital display

DgtadisplayX

IDLE1.1APP

025

152 530

8 3 8 . 8 3 8WEIGHT

1

COMP

8

Selector switch Control Panel

Figure 4.-727AEMS Annunciator and Control Panels

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4 .2 .2 P A T H G U I D A N C E A N D N A V I G A T I O NT h e A E M S a v i o n i c s m a k e n o i n p u t s t o e x i s t in g p a t h ^ g u id a n c e o r n a v i g a t io n e q u i p m e n t .H o w e v e r , a p p ro a c h p a t h g u i d a n c e m u s t b e a va i l a b le t o t h e p i l o t , an d a c c u r a t e v a l u e s o fg r o u n d s p e e d a n d d i s t a n c e f rom t o u c h d o w n m u s t be s u p p l i e d c o n t i n u o u s l y t o t h e a i r b o rn ec o m p u t e r .T h e 7 2 7 A E M S c o n c e p t is d e f in e d for use in a i r p l a n e s n o t e q u i p p e d w i t h a r e a n a v i g a t i o n( R N A V ) o r i n e r t i a l n a v i g a t i o n s y s t e m s . C o n s e q u e n t l y , a D M E s t a t i o n , n o t c u r r e n t l y ava i l -a b l e a t m o s t a i r p o r ts , i s r e q u i r e d a d j a c e n t t o t h e a i m p o i n t f o r e ac h r u n w a y .A l t h o u g h th e c o m p u t e r a l g o r i t h m c o n t a i n s e n e r g y c o m p e n s a t i o n fo r d e v i a t i o n s a w a y f r o mth e i n t e nde d g l i de s l ope , th e p i l o t m u s t m a i n t a i n a nomina l pa th r e a sona b ly c lose t o th eg l id e s lope a ng l e e n t e r e d i n t he A E M S c o m p u t e r . T h e p a t h r e f e re n c e c a n b e p r o v i d e d b yan IL S , . a V A S I , o r a ny o th e r sys t e m suc h a s a n a i r b or ne op t i c a l s i g h t , wh ic h as s is t s t he p i l o tin m a i n t a i n i n g a p r e d e t e r m i n e d a p p ro a c h p a t h .

4.3 C O M P U T E R A L G O R I T H MThe c o m pu te r a l g o r i t hm pr e d i c t s spe e d ve r sus d i s ta nc e p r o f i l e s , wh ic h a r e c on t i nu ou s ly u p -da t e d a t l e a s t onc e pe r s e c on d , a nd use s t he p r e d i c t e d p r o f i l e s f o r g e n e r a t i ng t he EPR , f l a p ,a n d g e a r c o m m a n d s a n d t h e f a s t/ s lo w i n d i c a t i o n . A s i n d i c a t e d in f i gu r e 5, the c o m p u t a t i o na n d d i s p l a y c o n c e p t s v a r y w i t h a p p r o a c h p h a s e .4 .3 .1 PHASE IIn Pha se I ( i n i t i a l a ppr oa c h) , t he c ompu te r f irs t loca tes an in i t ia l po in t ( IP ) d e f in e d as thep o i n t a t w h i c h th e f irst f lap c o m m a n d o c c u r s o n th e des i red dece le ra t ion prof i le . T h e c o m -pu t e d p r o f i l e f o l l ows a p r e de t e r mine d spe e d sc he du l e fo r s e qu e nc ing EP R, f l a ps , a nd g e a ra n d t e r m i n a t e s at the a l t i tude se lec ted by th e p i lo t fo r s tab i l iz ing in the l a n d i n g c o n f ig u r a -t i o n . T h e spe e d sc he du l e is t a i lored to m i n i m i z e p it c h a t t i t u d e v a r i a ti o n s o n f inal a p p r o a c ha nd t o m a x im iz e f u e l / no i se b e ne f i t s . A f t e r l oc a t ing t he IP , t he c o m pu te r p r e d i c t s a p r o f i les t a r t i n g w i t h t h e a c t u a l a i r p l a n e p o s i t i o n , s p e e d , a n d c o n f i g u r a t i o n , a n d t e r m i n a t i n g a t t h eIP d i s t a nc e . Th i s po r t i on o f th e pr e d i c t i on a s sume s t h a t th e t h r o t t l e s ha v e j u s t b e e n r e t a r de dto i d l e a n d t h a t th e c u r r e n t f l ap c o n f i g u r a t i o n (e.g., c l e a n) a n d i d l e powe r a re m a i n t a i n e da ll t h e w ay to th e I P wi th spe e d b r a ke s r e t r a c t e d . T h e d i f f e r e n c e b e t w e e n th e pr e d i c t e dspeed an d th e des i red speed at the IP is displayed o n th e fas t / s low indica tor . This ass i s t s th epilot in h i t t i ng the IP a t the des i red energy leve l . T h e E P R I D L E c o m m a n d is g ive n on thea n n u n c i a t o r p a n e l w h e n th e predic ted speed at the IP e q u a l s o r e xc e e ds th e des i red speed.T h e f i r s t flap c o m m a n d ( n o r m a l l y F L A P S 2) is also g e ne r a t e d us ing the Phase I logic.4 .3 .2 PHASE IIA f t e r th e f irst f lap c o m m a n d h a s b e e n g e ne r a t e d , th e c o m p u t e r s w i t c h e s t o th e Pha se IIlogic. In Phase II , the c o m p l e t e prof i le i s predic ted s ta r t ing wi th th e a c t ua l a i r p l a ne position,

1 4


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Vfinal

(a) Phase I-Prior to Flap Command

Step 1: Locate IP

Stabilizationpoint

Step 2: Predict V at IP assuming power cut DsplayAV Flash IDLE for AV > 0

"final

(b) Phase 11-Flap/Gear Commands8

Vfina

When AX = 0 Flash commandStore profile for

fast/slow reference

Xfina

Predict X at Vf jnaassuming next configurationhas just been selected

8EPR 1.1 andAPPEPRcommand based on speed only.

'fina

Figure 5.Generation of Flap/Gear/Thrust Commandsand Fast/Slow DsplayUsing Onboard Computer Algorithm

ORIGINALOF POOR15


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s p e e d , a n d c o n f i g u r a t i o n , a n d t e r m i n a t i n g a t the f inal speed se lec ted b y t he p i l o t . T h e pre-d i c t i o n a s s u m e s t h a t th e n e x t E P R , f lap , o r gear s e t t in g h a s j u s t been se l ec t ed . W h e n th ep red ic t ed p ro f i l e t e rm in a t e s a t o r l o w er th an th e t a rge t a l t i t u de se l ec ted by th e p i lo t , t h eassu med co mman d is i l l u m i n a t e d on the an n u n c ia to r p an e l . A t th i s ins tan t , th e p red ic t edspe e d- ve r sus - d i s t a nc e prof i le i s stored in the c o m p u t e r m e m o r y fo r r e f e r e n c e , a nd t he co m-p u te r beg in s p r ed ic t in g a new p r o f il e a s s u m i n g th e n e x t E P R , f lap o r g e a r s e t t i n g h a s j u s tb e e n se l ec t ed . T h e f a s t / s lo w d e v i a t i o n is d e t e r m i n e d b y e n t e r i n g th e s to r ed sp eed -v e r su s -d i s t an c e p ro f i l e w i th th e a c t u a l a i r p l an e d i s t an ce (D M E) to o b ta in th e des ir ed sp eed a t t h a ti n s t a n t . A f t e r a p p l y i n g a n e n e r g y c o rr e ct io n t o a c c o u n t f o r p a t h d e v i a t i o n s , t h e c o m p u t e rco m p ares th e ac t u a l sp eed to th e ( co r r ec ted ) des i r ed speed an d d i sp lay s th e d i f f e r e n c e asa n energy er ror on t he f a s t /s lo w in d ica to r . A f t e r th e ap p ro ach h a s b e e n s t a b i l i z e d , th efast /s low d isp lay ind ica tes energy dev ia t ions re la t ive to the f ina l approach speed and f l igh t-path se lec ted by th e pi lo t .4.3.3 P R O F I L E PR ED I C TI ONT h e prof i le pred ic t ion is accomplished as o u t l in ed in f igu re 6. D ece le r a t io n is c o m p u t e df rom the s in g le -deg ree -o f - f r eedo m dece le r a t io n eq u a t io n w h ich a ssu mes th e a i r p l a n e is in1-g f l igh t . T h e t h r u s t a n d d rag a re co m p u ted f ro m eq u a t io n s r ep r esen t in g s t eady s t a t ee n g i n e t h r u s t t ab le s an d t r imm ed d r ag p o la r s . Th ese eq u a t io n s a r e en te r ed w i th EP R , f l ap ,

a n d gear se t t ings tha t vary a long th e p ro f i l e in acco rdan ce w i th s to r ed sp eed sch edu le s .W i n d a t f l igh t a l t i t u d e i s der ived f rom ai rspeed a n d D M E g r o u n d s p e e d . T h e v a r i a t i o n o fw i n d a lo n g th e co m p u ted p ro f i l e is based o n a ty p ica l sh ea r mo de l .N u m e r i c a l i n t e g r a t i o n is u s e d to c o m p u t e th e speed versus d is tance prof i le in smal l s teps .D ece le r a t io n is in tegra ted to o b ta in sp eed w h ich is i n t e g r a t e d to o b ta in d i s t an ce . A t eachp o in t a lo n g th e prof i le , th e u p da ted a i r sp eed is u sed to u p d a t e th e i n p u t s ( e .g . , C L ) to thedece le r a t io n eq u a t io n . T h e E P R , f laps , an d gear a re seq u en ced a lo n g th e c o m p u t e d p r o f i l eat the ap p ro p r i a t e sp eeds . Th ru s t dy n amics an d f l ap /gea r ex ten s io n r a t e s are representedin th e p red ic t io n mo de l .4 .3 .4 A S SU M ED PA TH GEOM ETR YPrior to g l ide s lope cap tu re , the pro f i les are based on th e two-segm ent path geome try ind i-ca t ed in f igu r e 7 . This geo met ry is used only for the speed-versus-d is tance pred ic t ions, an dnot for genera t ing path gu idan ce inform at ion . S ince i t i s impossib le to pred ic t what pathwill ac tu a l ly be f lo w n u n de r o p e ra t io n a l co n d i t io n s prior to gl ide s lope capture , th e geome-tr y represents a gu ess as to w h a t is l ikely to o ccu r . If abo v e the gl ide s lope , it is assu medth e glide slope will be in tercepted at 305 m (1000 f t ) of a l t i t u d e . If below th e glide slope,th e assu med geo met ry dep en ds o n w h eth e r th e airp lane is above o r below th e I PGS ( th ep o in t w h ere the IP w o u l d b e located i f the ent i re decelera t ion occur red on the glide slope) .Since th e geometry is u p d a t e d prior to each path pred ic t ion (a t least once p e r second ) , th eassumed geometry wi l l t end to converge on the actua l pa th being fo l lowed by the airp lane .

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(a) Basic Deceleration Equation

Itoredthrust tablesStored drag8polars

Wind derived fromground speed (DME)and airspeed

Decelerationrelativeto ground\ \\- Pilot *input V \ Dl/-ktv - riiotinputComputedalong profile

\

\- True airspeedcomputedalong profileaProfile prediction assumesEPR/flaps/gearsequenced per desired speed schedule.

(b) Speed/Dstance Calculation

dV

from DME

X = Xir + / V,, AtC|C +/

At Variable time incrementcorresponding to0.5-kn speed change

-1 = 3v/3t

VT -VG - A R B shear profileassumed for pathpredictions

Figure 6.Profile Prediction Concept Using Onboard Computer

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IntialyTwo-Segment Path

Case 1: Above glide slope Case 2: Below glide slope

|305-mAGL\0000-ft)

Above IP C S Below IPGS

IPGS

After GS Cap and FL2 Command-One-Segment Pth+ Energy Comp

Start profile calculation on GSnIC hP= n + ^nV|c vp - V - - -

Actual V, h

Figure 7. Path Geometry Assumed for Profile CalculationsNot Used for Path Guidance

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A f t e r th e gl ide s lope h a s b e e n c a p t u r e d and f laps 2 c o m m a n d e d , th e p a t h is a s s u m e d to bet h e g l ide s lo p e an g le (TGS^ en te r ed in to th e c o m p u t e r by the pi lo t . T h e speed-versus-d i s t a n c e c o m p u t a t i o n is i n i t i a l i zed on the glide slope at the ac tu a l a i r p l an e d i s t an ce , b u tw i t h t h e sp eed ad j u s t ed to acc o u n t fo r a l t i t u de dev ia t io n s f ro m th e g l ide s lo p e . Th i s ty p eo f e n e r g y c o m p e n s a t i o n ( b a s e d on the p h u g o i d a p p r o x i m a t i o n ) w as u sed b y N A S A in theC V-990 sy s t em.

4.4 OPER A TI ONA s p a r t of the descen t ch eck l i s t , th e pilot sets u p t h e A E M S c o m p u t e r u s in g th e se lec torsw i t ch an d k e y b o a r d on the contro l panel ( f ig . 4 ) . A c t u a t i n g th e TEST posi t ion checksopera t ion of the disp lays. Turn ing th e selector swi tch to the other posi t ions displays d e f a u l tv a l u e s w h ich will be u sed by th e co m p u te r i f n o t m o d i f i e d by th e p i lo t . A n ex cep t io n i s th ew e igh t in p u t t h a t mu s t be en te r ed be fo r e each ap p ro ach . En t ry o f th e w e igh t in p u t p l acest h e c o m p u t e r i n t h e s t a n d b y m o d e .A f t e r m a k i n g th e n e c e ss a ry i n p u t s , th e pi lo t leaves th e c o m p u t e r in th e s t a n d b y m o d e u n t i lth e r u n w a y D M E sta t io n h as b e en t u n e d an d iden t i f i ed an d a f inal ap p ro ach co u r se in t e r cep tangle of 30 o r less has b e e n e s t a b l is h e d . W h e n e n e rg y m a n a g e m e n t g u i d a n c e is d e s i r e d , th ep i lo t ac t u a t e s th e C O M P U T E s w i tc h .Be f or e d i s p l a y i n g an y g u i d a n c e i n f o r m a t i o n , th e c o m p u t e r first p er fo rms a c o n f i d e n c e t e stto d e t e r m i n e w h e t h e r th e o p era t io n a l i n t e r lo cks h av e been c l ea r ed an d t h a t th e system isf u n c t i o n i n g p ro p e r ly . I f t h e co n f iden ce t e s t i s f a i l ed , t h e I N OP l igh t i s i l l u m in a ted o n th ean n u n c ia to r p a n e l , an d a s t a t u s message i s d i sp lay ed o n th e co n t ro l p an e l t o in d ica te th en a t u r e of the p ro b lem. If the co n f iden ce t e s t is p assed , th e exis t ing f lap posi t ion will bed i sp lay ed on the a n n u n c i a t o r p a n e l to i n d ica te th a t th e system is w o r k i n g . T h e aircrew thenflies th e ap p ro ach u s in g th e disp lays to d e t e r m i n e w h e n to s e t p o w e r and to e x t e n d f l apsand gear .N o r m a l l y , a slow ind icat ion wi l l be d i sp lay ed on the f a s t / s lo w in d ica to r w h en the system isfirst t u r n e d on , i n d ica t in g i t is not yet t i m e t o cu t p o w er to i d l e . As the ap p ro ach co n t in u es ,th e slow ind icat ion s lowly approaches zero , a t w h ich p o in t the E PR I D L E c o m m a n d isi l l u min a ted o n t h e an n u n c ia to r p an e l . I f the pi lo t pu l ls th e t h ro t t l e s to i d l e , th e a n n u n c i a t o rlight will go ou t and the fast /s low ind icator shou ld remain centered . If the l igh t is ignored ,th e ind ica tor wi l l cont inue to slowly move in the fast d i rec t ion . When in a c lean co n f igu r a -t i o n , a fast ind ica t ion beyond th e f i r s t index mark on the fast /s low d isp lay ind ica tes tha tairspeed will exceed the f lap placard at the IP. In this case, idle power an d speed brakessh o u ld b e u sed if it is desired to c o n t i n u e th e ap p ro ach . W h en th e ind ica tor recenters f romthe fast d i rec t ion , th e speed brakes shou ld b e r e t r ac t ed so t h a t the p o w er can be left a t id le .A s th e approach progresses , commands wi l l be gen e ra t ed on the an n u n c ia to r p an e l in thefo l lowing s e q u e n c e : E P R I D L E , F L A P S 2 , F L A P S 5 , F L A P S 15 , G E A R , F L A P S 25 ,E PR 1 .1 , F L A P S 30 , EPR A P P . T he aircrew should set the th ro t t les , f laps, and gear as soonas th e an n u n c ia to r l i gh t co mes on. The appropriate l ight is ex t in gu i sh ed w h en th e A E M S

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sensors indica te that throttles ha ve been set, flaps have star ted to move f r om the last posi-t i o n , or the g e a r is in t r a ns i t . A n e x c e p t i o n is the d ig i ta l d i sp l a y o f f lap pos i t i on whic hr e m a i n s i ll u m i n a t e d a t t he l as t c o m m a n d e d s e t t in g u n t i l |h e f inal a p p r o a c h a n d l a n d i n g f lapp o s i t i o n ( F L A P S 30) is a c h i e v e d . T h e t h r o t t l e s e t t i ng s u se d to e x t i n g u i s h t h e EPR l ight a rese lec ted to g ive t h e a p p r o x i m a t e s t e a d y s t a t e E P R i n d i c a t e d . W h e n a d v a n c i n g p o w e r , th ep i l o t s h o u l d r e a d j u s t t h e t h r o t t l e s a s r e q u i r e d a f t e r t h e E P R h a s s t a b i l iz e d .P r io r t o t h e F L A P S 2 c o m m a n d , t h e f a s t / s lo w i n d i c a t o r p r o v i d e s e n e r g y i n f o r m a t i o n b a se do n p r e d i c t e d s p e e d a t t h e I P . A f t e r th e F L A P S 2 c o m m a n d , th e fa s t / s lo w d i s p l a y i n d i c a t e sde v i a t i ons f r om a de s i r e d p r o f i l e s to r e d a f t e r the l a s t fl a p o r g e a r c om m a n d . S inc e the s t o r edprof i les beg in a t e x i s t i ng f l i gh t c o n d i t i o n s , th e f a s t/ s lo w i n d i c a t i o n will n o r m a l l y b e c e n t e r e da f t e r e a c h f l a p o r g e a r c om m a nd . I f t he a i r p l a ne e ne r g y l e ve l de v i a t e s f r om the s to r e d p r o -f i le , t he f a s t / s l ow ne e d l e w i l l i nd i c a t e t he de v i a t i on . No r m a l ly , t he p i l o t ne e d no t t a k e a nyc or r e c t i ve a c t i on other t h a n to r e c he c k t ha t EPR, f l ap s , an d g e a r a r e se t p r o p e r l y . T h e c om-m a n d l o g i c will a dva nc e o r de l a y t he ne x t c onf i g u r a t i on c ha ng e t o g e t b a c k on t he e ne r g ys c h e d u l e . A l o w e ne r g y s i t ua t i on wou ld result in de l a y ing th e n e x t f lap or g e a r c o m m a n d ,o r c ou ld b e c o r r e c te d b y a d d in g powe r i f ne c e s sa r y . I f pow e r i s no t a dd e d a nd e ne r g y g e t st o o lo w to be c o m p e n s a t e d b y d e l a y i n g th e n e x t c o m m a n d , s u c c es s iv e f l ap e x t e ns ions wil lb e c om m a nd e d a s spe e d a ppr oa c he s 1 .3 V g for the exis t ing f lap se t t in g . In th is case thea ppr oa c h wi l l be stabil ized a t a h ig he r a l t i t ude . T h e A E M S , w h e n f u l ly de ve lope d , shou ldp r o v i d e a c l e a r - c u t i nd i c a t i on o f a m i n i m u m en e r gy l i m i t , b e l o w w h i c h th e p i l o t shou ld a d dp o w e r . T h e pr e se n t 7 2 7 A E M S c o m p u t e r a lg o r it h m is d e f i c i e n t in th i s r e g a r d , b u t t h i s c ou ldb e cor rec ted in the ne x t de s ig n c yc l e .I f a n ove r spe ed s i t ua t i on de ve lops ( a f t e r t he fi r s t f l a p c om m a nd ) so t ha t t he a pp r oa c hc a n n o t b e s tab i l ized at the t a r g e t a l t i t ude u s ing th e a b o v e E P R , f l ap an d g e a r s e que nc e( e ve n b y e x t e nd ing f la ps a t t he p l a c a rd spe e ds ) , t he INO P l ig h t will b e fl a s h e d o n t h e a n n u n -ciator p a n e l . A FAST message wil l a lso be d i sp l a ye d o n th e c on t r o l pa ne l , an d th e c o m p u t e rwill a u t o m a t i c a l l y r e v e r t to the s t a n d b y m o d e . T h e pilot m a y b e ab le to c o m p l e t e a n a p -pr oa c h b y e x t e n d i n g th e gear sooner. Logic fo r c ha ng ing th e gear sequence in overspeeds i t ua t i ons c ou ld be a d d e d to the a lg or i t hm, if de s i r e d , in a s u b s e q u e n t d e v e l o p m e n tp r o g r a m .T o m a x i m i z e th e f u e l a n d noise benef i t s , it is desirable to in i t ia te th e de c e l e r a t i on f r om ac l e a n c onf ig u r a t i on . H owe ve r , if it is necessary to e x t e nd f laps d u r i n g th e in i t ia l approachpha se (e.g., A T C r e que s t s a spe e d r e duc t i on) , th e c o m p u t e r is p r o g r a m m e d to reset i tselfto genera te th e r e m a i n i n g c o n f i g u r a t i o n c o m m a n d s in s e q u e n c e . In o t h e r w o r d s , i t providesg u i d a n c e fo r op t imiz ing as m u c h of the approach as poss ib le , s ta r t ing f rom th e exis t ingc ond i t i ons .4.4.1 PILOT INPUTSThe pilot is r e qu i r e d to enter W E I G H T for every approach. The c ompu te r de t e r mine sV R E F 3 0 f r o m W E I G H T fo r display an d check by th e pilot. W h e n th e selector switch ist u r n e d to the other positions, a de f a u l t va l ue w i l l be displayed as indica ted in table 2. The

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Table 2.Pilot Inputs

Parameter Definition Default valueWeightVREF30VFINALField el

HMIN

GS angle

Airplane landing weight1 . 3 V S at f laps 30Desired final approach speedR u n w a y elevation

Desired height above the runway forstabilizing at VFINAL with flaps 30Glide slope angle

For display only1.3Vs +5knA s input from the cabin pressurecontroller500 ft-thepilot can set a higher(but not a lower) value

d e f a u l t v a l u e s will b e used by th e c o m p u t e r u n l e s s c o rr e ct e d by th e p i lo t . W h e n th e a i r p l a n epasses th e t h r e s h o l d o n a m i s s e d a p p r o a c h o r t o u c h - a n d - g o l a n d i n g , W E I G H T wil l be a u t o -mat ica l ly r e se t t o z er o a n d t h e c o m p u t e r r e t u r n e d t o t h e s t a n d b y m o d e . T h e o t h e r p a r a m -eters will b e r e t a i n e d at the las t app roach va lu es .4 .4 .2 INT E RL OCKSS ince the 727 A E M S can be u sed wi tho u t an IL S g l ide s lope , no beam in te r locks a re pro-v i d e d . T h e p i l o t a c t u a t e s t h e C O M P U T E sw i t c h m a n u a l l y w h e n o n a final approach cou r sei n t e r c e p t h e a d i n g . T h e c o m p u t e r will r e t u r n t o t h e s t a n d b y m o d e a n d will no t d i sp lay thef l ap p o s it io n w h e n C O M P U T E is a c t u a t e d u n l e s s th e f o l lo w i n g i n t e r lo c k s a re c leared : DMEs ignal rel iable Range d ecreas ing ; L e . , inbo u nd Range r a te g rea te r than 50 knThe las t i tem p rovid es a gross check for reasonable airspeed, w ind m easu rem ent , and inter-cep t head ing . F o r e x a m p l e , i f the local izer were approached on a 90 in te rcep t head ing , th er ange r a te in te rlock wou ld p rev en t AE M S engagem ent u n t i l a sha l lower in te rcep t ang le wasestablished.4.4.3 SELF-TESTT he com pu te r wi l l pe r form l im i ted se l f -t es ts befo re genera t ing energy m anag em ent in fo rm a-t ion fo r d isp lay . However , it will not be possible to cover all possible sources of error, soth e pilot will have to use h is j u d g m e n t to dec ide i f the system is giving correct info rm atio non a g iven approach .

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4.4.4 ICING C O N D I T I O N SW h e n th e en g i n e an t i - i ce s wi t ch i s t u r n e d on , t he c o m p u t e r a u t o m a t i c a l l y s e l ec t s a n al ter -n a t e s c h e d u l e u s i n g E P R 1 . 2 r a t h e r t h an i d l e for the d ece l e ra t i o n s eq uen ce . T h i s m a i n t a i n sth e e n g i n e . c o m p r e s s or s p e e d ( N j ^ 5 5 % ) r e q u i r e d f o r o p e r a t i o n o f t h e a n t i - i c e s y s t e m .W i t l i t h i s a l t e r n a t e s c h e d u l e , t h e A E M S d o e s n o t b e c o m e o p e r a b l e u n t i l F L A P S 1 5 a n dg e a r h a v e be e n e x t e n d e d . T h e r e s u l t i n g p r o c e d u r e s w o u l d b e q u i t e s i m i l a r t o t h os e c u r r e n t l yf l o w n b y A T A a i r l i n e s , a n d w e r e n o t i m p l e m e n t e d i n t h e A E M S c o m p u t e r f o r t h is f e a s i b i l i t ys t u d y .

4 .5 T Y P I C A L A P P R O A C H E ST h e n o m i n a l p r o f i l e c o m p u t e d b y t h e o n b o a r d c o m p u t e r w h e n l o c a t i n g t h e I P ( F L A P S 2c o m m a n d p o i n t ) is s h o w n in f igure 8 for a t y p i c a l l a n d i n g w e i g h t of 578 000 N (13 0 0 0 0 Ib ) .

. O p e r a t i o n a l s p e e d l i m i t a t i o n s a re s h o w n fo r r e f e r e n c e . T h e t a r g e t a l t i t u d e of 152 m (500 f t)is t h e m i n i m u m re c o m m e n d e d f o r v i s ua l f l igh t r u l e s ( V F R ) o p e r a t i o n . T h e p i l o t c o u l dselect a h i gh e r a l t i t ud e ( e . g . , fo r I F R ) a n d / o r a f a s t e r f ina l ap p ro ach s p eed (e .g . , fo r h e a d -w i n d s a n d / o r t u r b u l e n c e ) i f d e s i r e d , a n d t h e p r o f i le w o u l d b e a d j u s t e d a c c o r d i n g l y .A t y p i ca l d e l ay ed f l ap ap p ro ach p ro f i l e r e c o r d e d d u r i n g a p i l o t ed s i m u l a t o r r un i s presen tedin f i gu r e 9, w i t h th e c o m p u t e d n o m i n a l p r o f i le f r o m f i g u r e 8 o v e r l a y e d fo r co m p ar i s o n .A l t h o u g h a g l i d e s lope c a p t u r e a l t i t u d e of 915 m (3000 f t ) was u s ed fo r t h i s r u n , th e prof i l ec o m p u t a t i o n i s a u t o m a t i c a l l y a d j u s t e d to a c c o m m o d a t e a n y c a p t u r e a l t i t u d e r e q u i r e d fo re a c h i n d i v i d u a l a p p r o a c h a s p rev i o u s l y d i s cu s s ed (p a rag rap h 4.3.4).T h e s a m e d e l a y e d f lap p r o c e d u r e is c o m p a r e d in f igure 10 to one of the cu r r en t a i r l i n ep r o c e d u r e s u s e d for the f ue l / n o i s e co m p ar i so n s . T h e higher in i t i a l speed fo r th e D FA proce-d u r e p r o v i d e s ad d i t i o n a l en e rgy , r e l a t i v e to cu r r en t a i r l in e p ro ced u res , wh i ch a l lo ws p o werto be reduced to idle for several miles . The A E M S c o n c e p t uses drag m o d u l a t i o n for energyc o n t r o l . H e n c e , th e t h r u s t m o d u l a t i o n t h a t is a p p a r e n t for the cu r r en t a i r l i n e p r o c e d u r e isn o t necessary f o r t h e D F A ap p ro ach un t i l th e t a rge t a l t i t ud e i s r e a c h e d . T his t e n d s to o f f s e tth e o t h e rwi s e i n c reas ed p i l o t wo rk l o ad , a n d wo u l d e l i m i n a t e en g i n e t r an s i en t n o is e e f fec t sfo r p a r t o f t h e a p p r o a c h .

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727 Delayed flap approach Typical landing weight Still ar

m (ft)_ 900-

600-

o - 1 -

-(3000)-(2000)-(1000)

-152-m(500-ft)Target

I I

240

200

160

120

Flap placard

1 1 1 1 1 1 1 1 1 1 1 1

E P R A P R

Flaps 2Desired profile (min A0) computed on boardjllllllllll

1.3V,

trK f\rrf tTTTTTTTmTTTl OM I I

1.6 r

I1-2.8

A P R

\ rEP R 1.1 to initiate spool up

//////////V/'/V/V/V///Idle2 4 6 8 10 12 14

NMI from touchdownFigure 8.DesiredDeceleration Profile for 727 DFA

23


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Autopilotoff DFA-1 (dean, 220 knntiaapp) Typical landing weight~~ Still ar

m (ft)900-r (3000)

E 600--(2000) Raps30FChecklistcomplete

15 ^152-m \_ 2(500-ft) ^OM .Target , > ,

Flaps

-J Q

240

55% fo r en g in e in l e t an t i - i c in g . W h en th ei n l e t A N T I - IC I N G s w i tc h i s t u r n e d o n , i n te r l o c k l o g ic p r e v e n t s e n g a g in g t h e A E M S c o m p u t emo de u n t i l f l ap s 15 an d gea r h av e been ex ten d ed . I n add i t io n , a m in im u m p o w er se t t in gof EPR 1.2 is used in lieu of the IDLE, EPR 1.1 schedule. The procedures for icing condi-t i o n s w o u ld b e similar to c u r r e n t A T A air l ine procedures an d were n o t i n v es t iga ted in th iss t u d y .T h e sp eed sch edu le s are u sed by the c o m p u t e r in predic t ing decelera t ion d is tances for thedesi red f l igh t prof i le . T h e c o m m a n d s d i s p l a y e d to the pilot wil l occur at the sp eeds sh o w nif the airp lane decelera tes exact ly as p red ic t ed . The flap and gea r co mman ds are based onth e distance pred ic t ion a n d m a y b e g iv en a t higher o r lower speeds i f the ac tu a l p ro f i l estarts to dev ia te f rom th e predic t ion . T h e E P R c o m m a n d s a re de te rmin ed b y sp eed o n ly ;t h u s , f laps and gear ex tension wi l l a lways be in the same seq u en ce , b u t will n o t a lw ay so c c u r at the sch edu led sp eeds . T h e E P R co mman ds w i l l a lw ay s occur at the sch edu ledspeeds, b u t seq u en c in g w i th r e sp ect to the f l aps and g e a r c o m m a n d s will v a ry .

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Table 7.-AEMS Design Criteria

Required NAVAIDS DME collocated with path reference Path reference (VASI, ILS, orother) ILS for simulator study

Wind andweather CAT Iceiling/visibility Tailwinds to 10 kn Compatible with inlet anti-icing (stabilized approach for wing deice)

AFCS compatibility Suitable forcoupled ILS autopilotapproaches No change to autopilot/flight director Autothrottles not required

Thrust scheduling Nonicing Icing Thrust displays

Idle allowable to flaps 25; set EPR 1.1 prior tof laps 30; set final EPRprior to final speedN, >55%ALERT light remains on until throttles arereset

Landing flaps profiles based on flaps 30Configuration Scheduling

Stabilized Above 152-m (500-ft) VFR; 305-m (1000-ft) IFR Gear down Above 305 m (1000 ft)

Speed/path controlwith normal pilot skills 1-dot deviation Stay in trim. Beable to take hands off (or A/Pdisconnect) at

91 m (300 ft) and stay within 5 kn/2 dots at 61 m (200 ft)Speed/altitude constraintscurrent ATC and OPS manual, except:

Use 1.3 Vs reference for all flaps (plastic bugs set manually) Stay 10 kn below placards Stay on front side of dragcurve

Visibility and comfort 6


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Table 8.-SpeedSchedule for Winds to 10 kn

CommandgeneratedFlaps 2Flaps 5Flaps 15GearFlaps 2 5E PR 1.1Flaps 30A P R E P Ra

Landing weight calibrated airspeed, knGW = 488 000 N

(110 000 Ib)188170160151139130122120117

G W = 578 000 N(130 000 Ib)200185174165152143134131128

GW= 686 000 N(154 500 Ib)215203191181167159147144140

aFinal approach speed, (Vref + 5 kn) no command

Table 9.Speed Schedule for 30-kn Headwind

CommandgeneratedFlaps 2Flaps 5Flaps 1 5Gear downE PR 1.1Flap 25Flap 30A P P E P Ra

Landing weight calibrated airspeed, knGW = 488 000 N(110000 Ib)

188170160156155143136135132

G W = 578 000 N(130 000 Ib)200185174170169155148147143

GW = 686 000 N(154 500 Ib)215203191186185170162160155

aFinal approach speed (Vref + 20 kn) nocommand

49


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Table 10.SpeedSchedule ComputationConcept

Equations= Vfef + 5-computed from weight ( G W )

VC O M M A N D = V N O M I N A L + K G W < G W - 1300001 ,+ K V (VFINAL- VAPP)I oilotilot inputs-Command speedto be computed

Flaps 2Flaps 5Flaps 15GearFlaps 25E P R 1.1Flaps 30A P R E P R

VNOMINAL200185

1741654152143134131

KGW

0.000600.000750.000700.000700.000650.000650.000600.00055

KV

000

0.3330.21.730.9321.068

I;

T he flaps ve rsu s speed schedu l e s a re se lec t ed t o min im ize t he p i t ch a t t i t u de va r i a t ionsrequ i red to m a i n t a i n 1- g f l ight d u r i n g f lap extension on final a p p r o a c h . This is desi rablefo r glide slope tracking both by the pilot an d au top i lo t . F o r t u n a t e l y , th e m i n i m u m A 0schedu l e a l so p rov ides adequ a t e speed marg in s from safety l imi t s , is compa t ib l e wi th A T Cspeed l imi ts , and i s a good com prom ise wi th respect to fue l and noise ben ef i t s .To maximize the fue l /noise benef i t s , i t i s desi rable to de lay gear ex tension as long as pos-s ib le . The large gear drag increment d iss ipa tes energy r ap id ly , t h u s sho r t en ing t he d i s t ancethat can be f l own at idle power . In the selected procedu re , th e gear is extended in sequencefo l lowing f laps 15 . This is consis ten t w i th cu rren t Boeing p i lo t t ra in ing proced ure s fo rn o r m a l IL S app roaches and , in combinat ion wi th th e thrus t schedu le , resu l t s in gear ex ten-s ion s l igh tly above 305-m (1000-f t) a l t i t u de du ring a de layed flap approach .F or nonic ing condi t ions , th e decelerat ion phase of the approach is in i t ia ted b y re tard ingthrottles to idle. T he decelerat ion is arrested b y reapp ly ing t h ru s t in two steps, f irst toEPR 1.1 and t hen to normal approach power se t t ings . T he first step to EPR 1.1 ini t iatesengine accelerat ion to a power se t t ing near th e surge b leed va lve opera t ing p oin t from whichf u r t h e r accelerat ion can be obta ined more rap id ly when requ i red . T he increased thrus t a tE P R 1. 1 redu ces th e rate of airspeed decay which lessens th e l ikel ihood of u nde rshoo t ing

5 0


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th e f inal approach speed and ex tends the overa l l dece le ra t ion d i s tance . T he d i s tance effectis used to a d j us t the po in t a t wh ic h the gear down speed i s r eached . In l igh t win d cond i t ions ,E PR 1 .1 i s s e t j u s t p r io r to s e lec t ing l and i ng f laps. H o w e v e r , i n s t r o n g h e a d w i n d s , t h edece le ra t ion becom es com pres sed wi th r espec t to g r o u n d d i s t a n c e , so t h r u s t is a d v a n c e d toEPR 1.1 sooner fo r h e a d w i n d s .6 .2 .2 COM PUT E D FL IG HT P R O F I L E SN o m i n a l f l igh t prof i l es co r respond ing to the se lec ted speed s chedu les a re s h o w n in f igures2 6 and 27 for a r a n g e of w e i g h t an d w i n d c o n d i t i o n s . T h e p r o f i le s w e r e c o m p u t e d on thef l ight c o n t ro l s t e c h n o l o g y m i n i c o m p u t e r ( N O V A ) u s i n g t h e p a t h p r e d i c ti o n m o d e l d e f i n e dfor the a i rborne com pu te r . T hese par t i cu la r p ro f i l es were in i t i a ted f rom a f laps 2 c o n f i g u r a -t ion . If i n i t i a t e d f r o m a c l ea n c o n f i g u r a t i o n , p o w e r w o u l d n o r m a l l y be cu t a t a h i g h e rspeed , and flaps 2 w o u l d b e c o m m a n d e d a t a b o u t t h e s a m e p o i n t a s t h e p o w e r c u t p o i n t s( I D L E ) i n d i c a t e d o n cu rves ( s l igh t va r ia t ions d u e t o effect s o f f lap e x t e n s i o n r a t e s an den g in e s po o l d o w n t i m e ) .T h e prof i l es in f igure 2 6 i l l u s t r a t e t h a t w e i g h t v a r i a ti o n s h av e l i t t l e effect on the d e c e l e r a -t ion dis tance and general shape of the prof i les in s t i l l a i r condi t ion. The gear extens iona l t i t u d e increases sl ightly with we igh t . How ever , the a i r speed a lso increases so the t im eava i lab le for accom pl i sh ing check l i s t i t em s is essent ial ly the s a m e . A s i n d i c a t e d in f igure27 , the p rocedu re becom es m ore com pres sed by head win ds . Co n t r ib u t ing fac to r s a re ther e d u c e d groundspeed and the h igher a i r speeds s chedu led fo r f laps 25 and f l aps 30 . (Cu r ren tp rocedu res spec i fy increas ing the f ina l approach speed by one-ha l f the r epor ted windspeed p lu s all of the g u s t ; not to exceed a 20-kn total increase.) T he higher f ina l airspeedsrequire less speed reduct ion ( ini t ia l speeds n o t c h a n g e d ) a n d also place th e a i r p l a n e f u r t h e ron the f ron t s ide of the drag cu rve, resu l t ing in mo re rapid decelerat ion. These ef fec tsare com p ensa ted by ad van c ing the E PR 1 .1 com m a nd speed in s t rong headw inds .6.2.3 P R O F I L E A N A L Y S E SS o m e of the factors cons idered in select ing the f l ight prof i les a re discussed in the fo l lowingparagraphs .6.2.3.1 Pi t ch At t i t udeThe var iat ion of pi tch at t i t u d e with speed is shown in f igure 28 for t r imm ed 1-g f l ight ona 3 glide s lope at a typ ica l l and ing weigh t . T he speed s chedu les for f lap ex tens ion areselected to m i n i m i z e the p i tch a t t i t ude var ia t ions f rom th e f inal approach a t t i t ude asind ica ted .6.2.3.2 Speed MarginsT he re la t ionship of the f lap versus speed schedule to va r ious operat ing limits is indicatedin f igu res 29 t h r o u g h 31. Reasonable m arg ins a re provided relat ive to f lap placards and1 . 3 V S .

5 1


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3Glide Slope StillAir

V,K C A S

V,K C A S

200

180

160

140

120

220

200

180

160

140

120

W = 488 000 N(110 000 Ib)

W = 578 000 N(130000IW

Idle

Id le

Flaps 2 (188 kn )

Flaps 2 (200 kn)

V,K C A S

220200

180160

140

120

W . 686 000 N(154 000 Ib)Idle

4 6NMI from touchdown

Flaps 2 (215 kn )

10

Figure 26. E f fe ct of Weight on PredictedDeceleration Profiles

1 2

52


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V,KCAS

220

200

180

160

140

120 I-

30-kn Headwind

E PR 1.1

E P R A P P

3Glide Slope578 000-N (130 OOfrJb) GW

Id leFlaps 2 (200 kn)

V,KCAS

Flaps 2 (200 kn)Idle

V,KCAS

r-152m (500ft) attitudeT i I

4 6NMI from touchdown

Flaps 2 (200 kn)

10 12

Figure 27.-Effectof Winds on Predicted Deceleration Profiles

53


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58/103

686000-N(154500-lb)GWATC limits:

below 3048m (10000ft)240-i

2 2 0 -

C A S -kn

160-

140-

120J

r below 905m(3000ft),-Plotselect:/ Flaps2

SYM Speed for constant 0 =2.3

A, D, X Speed for selecting next flap/gear/E P R during decelerationM Minimum speeds for normalmaneuvering (OPS manual)

Flapplacards

Stabilized""IT __fft

25 30 Flap detent0 10 20 30 40 50 60 70 80

Figure30.DFA SpeedMargnsRelative to Flight LimitsatMaxmumLandingWeight90 Flap screwtravel, %

A t h i g h l a n d i n g w e i g h t s t h e r e is a s l igh t conf l i c t wi th t h e A TC g u i d e l i n e o f 2 0 0 - k n m a x i -m u m w h e n b e l o w a n a l t i t u d e o f 9 1 5 m (3000 f t ) in the t e rm ina l con t ro l zone . However ,if th i s becom es a p rob lem , f l aps 2 cou ld be u sed fo r the in i t i a l approach phase a t h ighw e i g h t cond i t ions .At low weigh t cond i t ions , the d e l a y e d flap approach speed s chedu le r equ i r es speeds s lowerthan the approach m a neu ver speeds cu r re n t ly pu b l i shed in the 727 Opera t ions M anu a l .T h is cou ld p resen t an opera t iona l a nd /o r t r a in ing p rob lem , s ince a i r c rews m em or ize thespeeds shown in the op era t ions m anu a l (based on m ax im u m land ing weigh t ) and t r ea t themas m inim u m speeds for al l land ing weights . S ince this is an op erat ional as wel l as an engineer-ing concern, resolu t ion of the ques t ion has been defe r red un t i l th e nex t phase of the A E M Sdeve lopm ent p rogram t h a t would p rov ide fo r airline pi lot eva lua t ions and fu r ther eng ineer -ing deve lopm ent of the concept.T he preferred solution f rom an engineering and safety point of view is to im plem ent anindependen t speed m oni to r based on ang le -o f -a t t ack in fo rm a t ion ob ta ined f rom the exis t ing727 s t ick shaker sys tem. Other less expens ive poss ibi l i t ies are to m a n u a l l y se t plas t ic "bugs"on the airspeed indicator a t 1.3 V s fo r each flap position as part of the A E M S s e t u p proce-d u r e , or to use the published (higher) speeds and accept th e larger pi tch excurs ions . U s e o fthe m anua l ly s e t bugs was as sum ed in def in ing the av ion ic conf igu ra t ion and f l igh t p ro f i l esfor th is feas ibi l i ty s tudy.

55


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ATC limits: 488 000-N (110 000-lb) GWaa11a n- below 3048m (10-000 f t)-

240 H

2 2 0 -

200-

180-VCAS'kn

160-

140-

120-

100-

SYM Speed for constant 6 = 2.5_ A, D, X Speed for selecting next flap/gear/E P R during deceleration

M Minimum speeds for normalmaneuvers (OPS manual)below 905 m (3000 ft) FlaPPlacards

Milot selectFlaps 2

Trr1.3V. MM

I-

**1.3V, ^15

Stabilized

25 30 Flap detent90 Flap screwtravel.%0 10 20 30 40 50 60 70 80

Figure 31. D F A SpeedMargins Relative to Flight Limits For Minimum Landing Weight6.2.3.3 Fuel TrendsF u e l t r e n d s w e r e s t u d i e d u s i ng p e r f o r m a n c e d a t a a n d u n p i l o t e d d i g i ta l c o m p u t e r r o u t i n e sto de te rmin e i f a d i f f e r e n t sp eed sch edu le w o u ld in c r ease th e fue l ben e f i t s o f th e p ro cedu re .A s sh o w n in f i gu re 3 2 , th e m in imu m A O sch edu le clo se ly ap p ro x ima tes th e sp eeds fo r ma x i -m u m n a u t i c a l m i l es p e r p o u n d o f f u e l , a s s u m i n g t h r u s t is t r i m m e d for a 3 g l ide s lope . Witht h r u s t f ixed at an arbi t rary va lue (e .g . , id le) , f u e l co n su mp t io n v a r ie s p r ima r i ly w i th e l ap sedt i m e , so high speeds a re best. I t was c o n c l u d e d t h a t fo r pract ica l D F A speed schedu les n os igni f icant i m p r o v e m e n t c o u l d be obta ined re la t ive to the m i n i m u m M sch edu le .6.2.3.4 Deceleration CapabilityThe l o n g i t u d in a l dece le ra t io n cap ab i l it y of the 727 w h e n t r i m m e d on a 3 glide slope instill air is s h o w n in f igures 33 and 34 for two power se t t ings: Id le ( f ig .33)

56


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578000-N (130000-lb) GW

240-1

2 2 0 -

200-

' C A S- 180-kn160-

140-

SY M Speed for constant 6 = 2.4

Note: Shaded area denotes range ofspeeds giving fuel mileagewithin 1% of best nmi/lb

r'i n i rrStick shakerd = 45

1 2 0J o|0 1 02

20 30 40 I505

6015170

2580

3,0 Flap detent90 Flap screwtravel, %

Figure32.Comparison of Constant 6 Speed Schedule to Best FuelMleage,MnmumDrag, and Stick-ShakerSpeeds

EPR 1.2 ( f i g . 34); t h i s is the m i n i m u m p o w e r s e t t i n g t h a t wil l e n s u r e Nj > 5 5 % ,r e qu i r e d fo r i n l e t a n t i - i c i ng o n cold d a y c o n d i t i o n s

It is a p p a r e n t t h a t th e a b i l i t y to dece le ra te o n g l ide s lope in a c l e a n c onf ig u r a t i on is m a r g i n a l ,ev en a t i d l e pow e r . W he n i n l e t a n t i -i c i ng i s r e qu i r e d , a g e a r d ow n, f laps > 1 5 c onf ig u r a t i onm u s t b e u s e d .6.2.3.5 Noise TrendsNoise t r end da ta showing the separa te effec ts of va r y ing t h r us t , spe e d , a nd c onf ig u r a t i onat constant altitude-304 m (1000ft)-were developed for reference in def ining the f l ightprof i les . Unl ike a s tab i l ized approach, the de layed f lap pr oc e du r e a l l ows pow e r s e t t ing sa nd spe e ds du r ing th e dece le ra t ion phase to be spe c i f ie d i nd e pe nd e n t ly ( w i th in b r oa dl imi ts ) of f lap position. With a range of possib le prof i les , the noise t r end da ta providedins ight i n t o th e ef fec ts o f ind iv idua l pa r a me te r va r i a t i ons o n t h e to t a l c ompu te d no i se .The noise trends concerning three aspects of the procedure were of particular interest: Power Setting-Thrust l eve ls near id le are requi red to ini t ia te the decelerat ion in a cleanc onf ig u r a t i on on a 3 glide slope. However , higher power se t t ings are preferable with

respect to eng ine response t i m e . H e nc e , th e AEMS des ign c r i te r ia ( tab le 7 ) requi re ad -

57


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oo >ou

< .' 8< u0

0.20.40.60.8

-1.01 .2-1.4-1.6-1.8-2.0-2.2-2.4

en

' ,,f. "gQ----

Airs

**.-*

*30

727-200/JT8D-9 Standard day 915m (3000 ft) altitude 578000-N (130 000-lb)GW Flaps 0

Gear upGear down

120 130 140 150 160 170 180VE, KEAS

190 200 210 220

Figure 33.Acceleration at IdleThrust on3Glide Slopev a n c i n g p o w er to E PR 1 .1 pr ior to se lec t ing th e f inal f l ap s . Ex cep t for the adv e r seef fec t o n n o i se , i t w o u l d b e desi rable to se lec t th e higher power se t t ing ear l ier in theap p ro ach ( e .g . , immed ia t e ly a f t e r gea r ex ten s io n ) . Th e n o i se t r en ds sh o w n in f igures35 and 36 i n d ica te th a t i n c r eas in g th r u s t f r o m I D L E to EPR 1 .1 increases center l inenoise a b o u t 3 E P N d B fo r u n t r ea t ed n ace l l e s at the speeds an d co n f igu r a t io n s ofi n t e r e s t . Th i s w a s considered to be a l a rge en o u gh n o i se in c r emen t to w ar ran t r e t a in -in g i d l e p o w er a s lo n g a s p r ac t ica l . A l th o u gh th r u s t r edu c t io n s a r e l ess effective at thehigher speeds du e t o t he air f rame noise contr ibu t ion , total noise decreases wi th thrustr e d u c t i o n s al l the w ay to id le power .Speeds Total a i rp lane noise is c o m p u t e d as the l o ga r i th mic sum of the a i r f r ame anden g in e co n t r ibu t io n s . For a given t h r u s t level , a i rsp eed in f l u en ce s to t a l n o i se th ro u ghth e a i r f r ame noise co n t r ibu t io n a n d t h r o u g h th e t ime du r a t io n effect in the E P N Lc a l c u l a t i o n . A n increase in airspeed tends to increase th e a i r f r ame n o ise co n t r ibu t io n ;b u t , t h r o u g h the t ime dura t ion ef fec t , a lso tends to r edu ce the E P N L . T h e overa l lef fec t of the speed increase on the E P N L d e p e n d s o n w h ich is larger, the air f ramenoise effect or the time du ra t io n e f f ec t . This resu l ts in the crossover of the constan ta i r speed l ines tha t is ap p a ren t in f igu r e s 35 and 36 . A t h igh p o w er se t t i n gs w h ere

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o2


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mo92r

90oOJI88O4-cvO

86 L

Quiet NacelleE P R 1.3

(3000)5000 10000

Fn/6 per engine, N (Ib)

(4000)15000

98r

96

m 94oa.UJ0)'6co >c~c

92

90

88

86

Untreated Nacelle

727-200/JT8D-9 3glide slopeapproach 305-m (1000-ft) altitude 578 000-N (130 000-lb)GW

E P R 1.1Trimmed

Idle (1000) (2000) (3000)5000 10000

Fn/6 perengine, N (Ib)

E P R 1.3

(4000)15000

Figure 35.Noise Variation with Thrust and Speed, Flaps 2 Gear Up

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mT30.UJ

o

92

90

~ 88c0)O

86

h0

CQoa.

oc0)c

98

96

94

92

90

88

86

Quiet Nacelle

Gear down\

uear aown160KEAS_.,- ^

(2000) (3000) (4000)5000 10000

Fn/6 per engine, N (Ib)

Untreated Nacelle

15000

E P R 1.3 727-200/JT8D-9 3glide slope approach 305-m (1000-ft) altitude 578000-N (130 000-1b) GW Trimmed7

E P R 1.2

Gear down v160KEAS \E P R 1.1

(1000) (2000) (3000) (4000)5000 10000

Fn / 6 pe r engine, N (Ib)15000

Fgure36.Noise Variation wth Thrust and Speed, Flaps 25 Gear Up

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92 ._ Untreated Nacelle

90

Center! nenoise, 88EPNdB

86

84 L

3Glide slope approach 305m (1000-ft) altitude-.-- 578 000-N (130 000-16) GW

15

9 2 r

90

Center! nenoise, 88E P N d B

86

84 L-

Quiet Nacelle

I100

Idle thrustGear downGear up

12 0 140 160 180True airspeed, kn

200 220 240

Figure37.-727-200/JT8D-9Noise Trends

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a r e b o th e x t e n de d , t he a d d i t i o na l no i se i nc r e m e n t du e t o t he g e a r i s l a rg e r a t t heh i g h e r s p e e d s a n d r e d u c e d f l ap d e f l e c t i o n s . F o r t h e d e f i n e d 7 2 7 s p e e d s c h e d u l e s( t ab l e 8 ) t h e g e a r is e x t e n d e d in s e q u e n c e fo l lo w in g f l aps 15, so the n o i s e i n c r e m e n td u e to g e a r e x t e n s i o n is l e ss than 1 E P N d B .

F r o m t h e n o i s e t r e n d d a t a i t w a s c o n c l u d e d t h a t : P o w e r s e t t in g s s h o u l d b e t h e m i n i m u m c o n si st en t w i t l i sa f e ty a n d p i lo t a c c e p t a nc e The se l e c t e d DFA spe e d sc he du l e s a ppe a r r e a sona b l e for n o i s e a b a t e m e n t Flap and gear extens ion should be de layed as long as practical , and gear extension

shou ld no t b e s c he d u l e d p r i o r t o f laps 5

6.3 C O M P U T E R A L G O R I T H MThe a lg or i t hm c onc e p t a nd ope r a t i o n a r e p r e v ious ly d i sc us se d i n s e c t i on 4 .0 . Ad d i t i o na le n g i n e e r i n g de t a i l s a nd r e su l t s o f t he a l g o r i t hm de v e lop m e nt pha se o f t he s t u dy a r e p r e-se n t e d b e low.6.3 .1 D E V E L O P M E N T S E Q U E N C EA f t e r r e v i e w i n g th e CV - 990 sys t e m, a basic a lgor i thm w a s f irs t d e v e l o p e d for the c o n f i g u r a -t io n s e q u e n c i n g p h as e of the approach ( see f ig . 5b) . T h e f l igh t c on t r o l s t e c hno log y min i -c om pu te r ( N O V A ) wa s use d t o a ll ow a lg or i t hm de v e lopm e nt t o p r oc ee d i n pa r a l l e l w i th t he7 2 7 a i r p l a n e s i m u l a t i o n d e v e l o p m e n t . F u r t h e r , t h e N O V A p r o v i d e d a c o n v e n i e n t a n de c o n o m i c a l w a y t o o b t a i n c o m p u t e d p r o f i l e s fo r p a r a m e t r i c s t u d i e s a n d s i m u l a t o r c h e c k o u t .T h e a l g o ri th m w a s t h e n a d d e d t o t h e p i lo t e d s i m u l a ti o n f o r f u r t h e r d e v e l o p m e n t a n d e v a l u a -t i on . Be c a use o f size an d c o m p u t a t io n c y c le t i m e of the 727 a i r p l a ne s imu la t i on , i t w asnecessary to program th e prof i le predic t ion p o r t i o n o f th e a lgor i thm o n a se pa r a t e min i -c o m p u t e r ( V A R I A N ) in t e rf a c ed w i t h t h e m a i n s i m u l a t i o n c o m p u t e r ( E A I - 8 4 0 0 ) , w h e r e th er e m a i n d e r of the a lgor i thm w as p r o g r a m m e d .T h e basic a lgor i thm conta ined al l o f the e lements d iscussed in section 6.3.4. H o w e v e r , th ei n i t i a l i z a t i on r ou t i ne d i d n o t or ig ina l ly conta in provis ions fo r c o m p u t i n g t h e I P , an d th epa th g e om e t r y r o u t i ne i n i t ia l l y c on t a ine d on ly th e one - se g me nt pa th p l us e ne r g y c ompe nsa -t ion scheme ( f ig . 7 ). T h i s se tup genera ted all the c o m m a n d s an d displays necessary to f ly ac omple t e de l a ye d f lap a ppr oa c h , if s ta r ted f rom a su i t a b l e c ond i t i on . A l thoug h th e basicalgori thm d i d n o t pr ov ide a fas t / s low indica t ion prior to the powe r c u t , i t was c omple t e inall other r espec t s a n d w a s use d to eva lua te f l ight prof i les and to f u r t he r de ve lop th ea lgor i thm.

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W h e n th e basic a lgor i thm w a s f u n c t i o n i n g p r o p e r ly , th e s i m u l a t i o n w a s t h e n m o d i f i e d toi nc or por a t e the IP c o n c e p t fo r d r i v i n g th e f a s t / s l o w i n d i c a t o r d u r i n g th e i n i t i a l a ppr oa c hpha se (see fig. 5a). T h e c o m p l e t e a l g o r i t h m w as u s e d in the f inal s i m u l a t o r e v a lu a t i o n ,i n c l u d i n g th e t ime / f ue l / no i se b e ne f i t s c ompa r i sons , th e N A S A p i l o t e v a l u a t i o n , a n d subse-q u e n t B o e i n g d e m o n s t r a t i o n s t o A T A a n d A L P A p i l o t s .6.3 .2 P R O G R A M L A N G U A G ET h e a lg or i t hm w as or ig ina l l y de ve lope d on the N O V A in the F O R T R A N l a n g u a g e . T h ea lg or i t hm f or t he p i l o t e d s im u la t i on wa s p r og r a m m e d in c om pu te r a s se mb ly l a ng ua g e s onth e V A R I A N a n d EAI-8400 c o m p u t e r s . R e f i n e m e n t s d e v e l o p ed o n th e s imu la to r we r e t he nincorporated in the N O V A p r o g r a m .T h e F O R T R A N l i st i n g a t t a c h e d t o t h e A E M S a v i o n i c s p e c i f ic a t i o n ( re f . 3 ) w a s o b t a i n e df ro m th e N O V A . W h i l e th e F O R T R A N l i s t i n g i s no t prec ise ly th e s a m e as the s i m u l a t o rp r o g r a m s , t h i s a p p r o a c h p r o v i d es a w o r k i n g p r o g r am i n a c o m m o n l a n g u a g e t h a t d e f i n e s t h ea lg or i t hm f u n c t i o n s w i t h o u t i n t r o d u c i n g e x t r a n e o u s i n s t r u c t i o n s p e c u l i a r t o th e s imu la t i on .6.3.3 CO M PA RIS O N W ITH CV-990 S YS TEMT h e 7 2 7 a lg or i t hm c onc e p t is ope r a t i ona l l y s imi l a r to the CV-990 f rom th e pilots' v i e w-po in t . H owe ve r , t he r e a re se ve ra l d i f f e r e nc e s in the d e t a i l e d i m p l e m e n t a t i o n . T h e d i f f e r e n c e sr e s u l t e d pr ima r i l y b e c a use o f th e m o r e n u m e r o u s c o m m a n d s t o be g e ne r a t e d fo r th e 7 2 7an d d i f f e r e n c e s in g e a r / f l a p /powe r s e que nc ing ; i.e.,

CV-990 commands 727 commandsIdle IdleGear down Flaps 2Flaps 10 Flaps 5Flaps 36 Flaps 15Approach power Gear down

Flaps 25EPR1.1Flaps 30Approach EPR

dV rT h e CV-990 use s both forward a n d b a c kwa r d i n t e g r a t i on o f - ^ t o c o m p u t e th e profi les,dV rw h e r e a s the 727 uses only forward integra t ion of ... . The CV-9900 a lgor i thm precom-d X

putes an d stores m a x i m u m a n d m i n i m u m V -X decelerat ion profi les based o n f lap extensiona t m a x i m u m a n d m i n i m u m s pe ed s fo r three prese lec ted win d cond i t ions . T h e m a x i m u m a n dm i n i m u m p r o f i l e s for the pr e va i l i ng w inds a re ob ta ine d f r om th e stored prof i les by inter-po la t i on . T h e fas t / s low indica tor is scaled relat ive to these energy l imi ts wi th th e des ired

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prof i le t a k e n as m i d w a y b e t w e e n the two ex t r emes . T h e 7 2 7 prof i le pred ic t ion takes th eprevai l ing w in d in to acco u n t d i r ec t ly an d bases th e p red ic t io n o n th e des i r ed p ro f i l e r a th e rth an on the energy l imi t p rof i les . Al though th e fast /s low ind icator does n o t p ro v ide a ni n d ica t io n o f en e rg y l imi t s , t h i s f ea t u r e co u ld be added i f r eq u i r ed ; e .g . , by a lso in t eg r a t in ga lo n g m a x i m u m an d m i n i m u m e n e r g y d i s s i p a t i o n s c h e d u l e s . Th e 7 2 7 a l g o r i t h m u s e s th es a m e e n e r g y c o r r e c t i o n ( p h u g o i d a p p r o x i m a t i o n ) as the CV-990 to c o m p e n s a t e th e p ro f i l epred ic t ions fo r dev ia t io n s f ro m th e glide slope. Ho w ev er , p r io r to g l ide slope c a p t u r e , the7 2 7 c o n c e p t e m p l o y s a n a s s u m e d p a t h i n t e r c e p t g e o m e t r y i n l ieu o f th e p h u go id ap p ro x i -m a t i o n .6.3 .4 C OM PU T A TI ON A L FLOW SEQU EN C EA m acro f lo w d iag r am o f th e a lgo r i th m i s p r e sen ted in f igu r e 3 8. A mo re de ta i l ed d i ag r am i sco n ta in ed in r e f e r en ce 3 .

A f t e r t h e n ecessa ry in p u t s h av e been mad e o n th e p i lo ts ' co n t ro l p an e l , t h e p r e l im in a ryc a l c u l a t i on r o u t i n e c o m p u t e s a n d s to r es t h e m i n i m u m o p e r a t io n a l sp e ed b o u n d a r y ( 1 . 3 V )fo r each f lap p o s i t io n . Th e ro u t in e a l so co mp u tes an d s to r e s th e co n f igu r a t io n se l ec t io nsp eeds to be u sed in p red ic t in g the desired fl ight profile for the d e l a y e d f l ap ap p ro ach . T h em i n i m u m speeds vary wi th a i rp lane weight on ly , whi le th e desired profile speeds alsod e p e n d on the final approach speed selected by the pi lo t and the s t a t u s of the an t i - i c in gswitch . This sec t ion of the algor i thm also se ts u p a l l co n s tan t s an d f lags r eq u i r ed to do thein i t ia l iza t ion for the V-X prof i le ca lcu la t ions.In the nav p arame te r u p d a t e sec t io n , th e sen so r in fo rm a t io n ca l ib r a t ed a i r sp eed , a l t i t u de ,d i s t a n c e , an d g r o u n d s p e e d are u p d a t e d , an d t rue a i r speed an d g l ide p a th dev ia t io n s areco m p u ted . Here , a lso , th e w a r n i n g flag ( I W A

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Delayed Flap Pocedure 727