## PETITIO N FO R EXEMPTIO N

Petitioner : Ti m McAdam s i ••J/\'iy '

Manager , America n Eurocopte rFligh t Simulatio n Cente r' : " ; (• FA AManagemen tRepresentativ e 270 1 Foru m Driv e ' - •' - , il : Gran d Prairie , T

X7505 2 (972 ) 641-379 6 Tim.McAdams@eurocopterusa.co m

-*^^*< ^ Cod e referenc e fo rwhic h exemptio n i s sought : 14CF R Par

t 60 , Appendi xC , Tabl e C2 AFul l Fligh t Simulato rObjectiv e Tests , requiremen t 4.b. 3 Exemptio n America n Eurocopte ri s seekin g relie ffro m th e requiremen t tha t an ygeometri cerro r betwee n th e Imag e Generato rey e poin tan d th e pilo t ey e poin tmus t b e 8 ° o rles s fo rth e EC17 5 Leve l D FF

S currentl ybein g designed . W e reques t tha ta geometri cerro ro f1 0 t o 1 2 degree s b e allowe d subjec tt o justificatio n an d agreemen t wit h Nationa l Simulato rProgra m Manager(NSPM ) i n accordanc e wit h helicopte rcharacteristic s an d trainin g needs , W e reques tthi s exemptio n base d o n th e following : I n orde rt o produc e a realisti chelicopte rtrainin g experience , th e pilo tmus t b e abl e t o accuratel yhove ri n clos e proximit yt o object s an d landin g areas. T o desig n a visua l syste m tha t realisticall yreplicate s thi s requiremen t require s tha t th e dom e b e a s clos e a s possibl e t o th e pilot . However , movin g th e dom e close rincrease s th e geometri cerror . America n Eurocopte rbelieve s tha t th e trad e of fo facceptin g a highe rgeometri cerro ri n orde rt o provid e a n enhance d hove ran d landin g experienc e greatl yimprove s th e helicopte rtrainin g experience . Ther e i s n o doub t tha tgrantin g thi s exemptio n wil l resul ti n a bette rtraine d pilot . Bette rtrainin g enhance s safet yan d safe rhelicopte roperation s ar e a substantia l benefi tt o th e publi ca

s a whole . Summaryfo rpublishin g i n th e Federa l Register : America n Eurocopte ri s seekin g a n exemptio n t o 1 4 CF R Par t 60 , Appendi xC , Tabl e C2A , 4.b.3 , specifically , allowin g a geometri cerro rgreate rtha n 8 degrees . Thi s exemptio n wil l allo wa n improve d desig n tha timprove s trainin g fo rhoverin g an d clos e proximit yt o object s operations . Improve d trainin g wil l significantl yenhanc e safety
. Atechnica l descriptio n follows :

## EC17 5 Ful l Fligh t Simulator , Level- D

EUROCOPTE R INDRASistemasS.A
. ll-April-201 1 Technica l Not e 

## Visua l Displa ySyste m Paralla xErro r& Dom e Scree n Size
.1 Introductio n

I t i s accepte d tha t wid e visua l field s o fview , bot h horizonta l an d vertical , wit h coverag e fo rperiphera l view , loo k

dow n o n side-doo rwindo wan d chi n windo wareas , greatl ycontribut e t o simulato racceptanc e b ypilot s an d trainin g effectiveness
. As fo rtoda ytechnolog ystatus , th e onl yfeasibl e solutio n fo rFo Vi n exces s o f210 ^

x60 ^ i s direc t projectio n o n a dom e screen , whic h combine d wit h adequat e scen e conten t an d textur e detail s als o provid e fo ra highl yaccurat e perceptio n o fheigh tabov e groun d an d groun d spee d magnitud e an d direction , a s require d fo rgroun d operation s an d lo wleve l hove ran d fligh ttasks. Fo rmulti-cre whelicopters , a significan t contributio n t o th e Visua l Displa ySyste m erro ri s th e s o calle d paralla xerro rt o distan t object s becaus e o fdifferen tcrewmembe ran d Imag e Generator/Projectio n Syste m ey e poin t referenc e positions . Th e Visua l Displa ySyste m typicall yinclude s a switchin g capabilit yt o se t th e I G viewpoin t t o th e pilot-flyin g ey e poin tfo rcritica l tasks s o th e parallaxerro ri s effectivel y cancelle d ou t (t o th e expens e o fa highe rparalla xerro rfo rth e pilot-not-flying)
. Fo rgenera l tasks , o rwhe n bot h pilo t an d copilo t ar e involved , a cente rvie wi s selecte d (mid-poin tbetwee n desig n ey e poin t positions ) s o th e parallaxerro rfo rbot h cre wmember s simultaneousl yi s minimized .

n Eyvfo M

M M Eyafo M Worl d Ofa(K l

Figur e 1 .-Dom e Projection , Paralla xError . A s a genera l rule , parallaxerro rfo rdistan tobject s migh tb e reduce d b yincreasin g dom e scree n radiu s bu t larg e dom e size , whil e increasin g erro rfo rclose robject s an d degradin g heigh tperceptio n o n ground , has als o sever e effect s o n othe rarea s o fth e simulato rfro m a practica l poin to fview . Astructure d decisio n proces s ha s bee n performe d fo rth e EC175 FFS- D Visua l DisplaySyste m design , leadin g t o a direc t projectio n dom e scree n becaus e o frelevanc e o fgroun d operation s an d lo wleve l hove r an d fligh t task s i n th e intende d training . Curren tpropose d desig n i s presented , togethe rwit h analysi s an d discussio n o n complianc e o fapplicabl e requirements , trainin g implication s an d impac to n genera l simulato rdesig n an d performance
.Thi s technica l not e ha s bee n compile d wit h th e objectiv e t o obtai n FA Afeedbac k

earl yi n th e simulato r desig n proces s whethe rpropose d solutio n migh tb e acceptabl e fo rEC175 FF S Leve l D qualification
.
2 Propose d EC175 VD S Desig n Rea l image , fron t projectio n spherica l dome . Interna l scree n radius : 3.25 m (10.7ft)
. Physica l scree n size : Horizonta l 240 e (+1209 ) Vertica l 90 9 (+30 2 up , -60 9 down ) Targe t imag e coverag e (cente rprojection) , optimize d fo rEC175 cockpi tFoV : Horizonta l >2109(±1059 ) Vertica l >80 9 (+25 9 up , -55 9 down ) Pilot/Copilo t Desig n Ey e Poin t position : ±580m m (22.8in ) righ tan d lef to fcenterllne .

Offse t250m m (9.8in ) af to fdom e center . I G vie wpoin t positions , selectabl e fro m Instructo rStation : Pilot , Center , Copilot
. Se e Figur e 2 fo rpropose d Fo Vcoverag e an d cockpi tstructur e maskin g fro m Cente rVie w(mid-poin t betwee n pilo t an d copilo t DE P positions ) an d Figur e 3 fro m Pilo tDEP , See Figur e 4 an d Figur e 5 fo rdom e scree n mai n dimensions .

Figur e 2. - EC17

5 Propose d VD

S Design , Fo

VCoverage , Pitot/Copilo tCente rView .Figur e 3. - EC17 5 Propose d VD S Design , Fo VCoverage , Pilo t Desig n Eye Point .

2.81 m 1.63 m <5.33ft )

(5.33ft ) Figur e 4 . - Dom e Screen , Sid e View .2 X580m m ( 2 X22.8in )

3.25 m (10.711 )

Figur e 5 . - Dom e Screen , Pla n View .

3 Curren t Requirement s an d Futur e Tren d 14CF R Par

t 60 , Appendi xC , Tabl e C2AFul l Fligh tSimulato rObjectiv e Tests , requiremen t4. b call s fo r"An y geometri cerro rbetwee n th e Imag e Generato rey e poin tan d th e pilo tey e poin tmus tb e 8 ° o rless" . Althoug h no t explicitl ystated , i t ca n b e assume d thi s geometr yerro rbein g dominate d b yth e parallax erro ri n th e dom e screen , plu s an ymisalignmen tan d distortio n i n th e I G an d projectio n system . B yth e othe rhand , th e Roya l Aeronautica l Society , Fligh tSimulatio n Grou p i s currentl ycoordinatin g a n internationa l effort , wit h contributio n fro m al l mai n participant s i n th e simulato rtrainin g industr y (regulator/qualifyin g authorities , helicopte ran d trainin g operators , aircraf tan d simulato rmanufacturers ) t o propos e a n updat e o fth e ICA O documen t9625 , Manua l o fCriteri a fo rth e Qualificatio n o fFligh t Simulatio n Trainin g Devices , a s a commo n basi s fo rconvergenc e o fnationa l standard s an d takin g int o accoun t lesson s learne d fro m th e hug e amoun to ftrainin g tim e accrue d t o date , curren ttechnolog ystatu s an d expecte d evolutio n fo rth e nea rfuture
. Draf tVolum e I fo rFixe d Win g (Aeroplanes) ha s bee n alread y publishe d fo rpubli creview , wit h Volum e ((fo rRotaryWin g (Helicopters ) followin g no wa tfina l elaboratio n stag e b yth e Internationa l Workin g Grou p fo rHelicopter s (H-IWG)
. A s a par t o fthi s effort , a serie s o fsystemati ctest s wer e conducte d t o evaluat e heigh tproximit y perceptio n an d effec t o fparalla xerro ro n approache s t o hover/landin g i n differen tdevic e type s (colllmated/dom e projection) , visua l dat a bas e are a resolutio n an d scen e conten t(lo wt o hig h resolution , hi-re s wit h plent yo ffamilia r3 D objects ) an d I G shif tinduce d visua l errors . A s fo rparalla xerror , experience d pilots/instructor s poste d n o objectio n u p t o 109 , wit h abou t12 9 bein g acceptabl e provide d arunnin g landin g wa s no t intended , whil e 15 9 an d abov e wer e consistentl yinterprete d a s som e proble m o n aircraf t handlin g o rpoo rpilo t performance
. I n accordanc e t o thes e results , initia l wordingo fth e draf tdo c9625 , Vol-ll , ask s I n th e Objectiv e tes t sectio n fo rmaximu m paralla xerro ro f109 , cente rimag e i n dom e scree n projectio n an d a limi to f20 9 fo r pilot-not-flyin g whe n pilot-flyin g viewpoin tselected .
4 Trainin g Implication s Whils t stric t complianc e wit h 14CF R Part6 0 requiremen tshoul d tak e t o dom e scree n siz e t o abou t4.25 m (14.0ft ) radius , followin g experienc e o fbot h E C a s trainin g operato ran d Indr a a s simulato rmanufacturer , full yI n agreemen t wit h H-IWG tes t results , th e propose d 3.25 m (10.7ft ) dom e scree n siz e wa s selecte d a s a compromis e valu e t o kee p parallaxerro rfo rbot h pilo tan d copilo twithi n 14CF R Par t6 0 requiremen tfo r practica l lo wleve l fligh t condition s (clos e objects , u p t o typica l collimatin g distance ) an d limite d t o H-IWG recommendation s i n genera l fligh t (distan tobjects ) whe n cente rImag e viewpoin tselected , stil l providin g adequat e margi n fo rIG/projectio n syste m misalignmen tan d distortion . Whe n pilot-flyin g viewpoin t selected , paralla xerro rfo rpilot-not-flyin g (abou tdoubl e tha n fo rcente rview ) i s kep twithi n th e H-IW G recommendations . Figur e 6 plot s th e estimate d parallaxerro ra tth e horizo n lin e a s a functio n o fobjec tdistanc e u p t o practica l infinit yfo rth e propose d 3.25 m (10.7ft ) dom e scree n size . See Figur e 7 fo rcomparison , showin g paralla xerro ri n a 4.25 m (14.0ft ) dom e scree n radiu s an d Figur e 8 fo ra collimate d system , wher e th e erro r trend s ar e Inverted : smalle rerror s fo rdistan tobjects , increasin g a s th e objec tI s gettin g closer .

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-12 0 -* 0 -« 0 -3 0 < 0 9 0 12 0 Figur e 7 . - Azimut h Paralla xError . Pilo t View , Dom e Scree n 4.25m , Cente rImage .

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a da g PjMlla^Ene(_O m da g t P m H »<_ C nD(_1 0 m . <!• < Pirall«i_Enor_2atn . 2 da g

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-12 0 -9 0 -6 0 -3 0 CO 9 0 12 0 Figur e 8. - Azimut h Paralla xError . Pilo t View , Collimate d Syste m € > 40m , Cente rImage .

Figur e 9. - Tota l Circula rErro rdu e t o Parallax , Helicopte ro n Ground , Fla t Terrain .

Pilo t View , Dom e Scree n 3.2Sm , Cente rImage .Figur e 1 0 . - Tota l Circula rErro rdu e t o Parallax , Helicopte ro n Ground , Fla tTerrain . Pilo t View , Dom e Scree n 4.25m , Cente rImage .

-12 0 -10 3 -9 0 -7 3 -6 0 Bo t -4 5 -3 0 -1 3 0 1 5 3 0 4 5 6 0 7 3 9 0 10 3 12 0 Figur e 11. - Tota l Circula rErro rdu e t o Parallax , Helicopte ro n Ground , Fla tTerrain . Pilo t View , Collimate d Syste m @ 40m , Cente rImage . Large rtha n propose d dom e siz e shoul d Increas e erro rfo rclos e object s and , mos to fall , als o degrad e th e perceptio n o fgroun d separatio n fo rfina l approac h t o hover , touchdow n an d groun d handling , whic h i s a commo n sourc e o fproblem s i n collimate d system s a s th e helicopte rI s systematicall ymiss-perceive d t o b e hig h abov e groun d level . See Figure 9 t o Figur e 1 1 fo restimate d tota l circula rerro r{roo tsu m square d Azimut h an d Elevatio n errors ) du e t o paralla xfo ra fla t terrain , bein g EC17 S cockpi tpilo tDE P heigh tabou t2 m (6.6ft ) whe n th e helicopte ro n ground . Th e propose d 3.25 m (10.7ft ) dom e scree n radiu s provide s minima l erro ran d excellen t screen-ey e distanc e matc h i n th e rang e -25 ^ t o -50 ^ fo rgroun d vie wthroug h cockpi tsid e an d chi n window s (re fFigur e 3)
. Fo rth e 4.25 m (14.0ft ) dom e thi s optima l vie wrang e i s shifte d forward , givin g somewha t degrade d heigh t perceptio n abov e terrai n immediat e aroun d th e helicopter , whil e th e collimate d system , i n accordanc e t o genera l experience , provide s quit e poo rperformanc e fo rheigh t perceptio n i n th e clos e groun d areas .5 Othe rConsideration s

5. 1 Motio n syste m Large rdom e siz e mean s increase d heigh to fDE P abov e motio n platfor m t o kee p th e sam e dow n vie w coverage , an d s o tota l dom e heigh t an d weigh to fcockpit , dom e an d uppe rprojector s suppor tstructures . Highe rcente ro fgravit yposition , increase d movin g loa d mas s an d correspondin g (quadratic ) growin g moment s o fInerti a shoul d Impos e o n th e Motio n Syste m payloa d handlin g requirement s clos e o rabov e limitin g performance s fo ravailabl e commercia l equipment . Dom e Radiu s Heigh t abov e Motio n Platfor m

DE P Tota l Dom e CoG 3.25 m 2.8 m (9.2ft ) 4.4 m (14.6ft ) >1.25 m (4.1ft ) 4.25 m

3.7 m (12.1ft ) 5.8 m (19.0ft ) >2.25 m (7.4ft ) Becaus e a coordinate d longitudinal/latera l displacemen tI s require d fo rPitch/Rol l displacemen tt o b e perceive d as a pur e rotatio n b yth e trainee , wit h n o parasiti clinea raccelerations , ther e i s a n inheren t couplin g amon g Pitch/Rol l an d X/ Yaxes . So , highe rDE P heigh tals o reduce s th e effectiv e workspac e availabl e fo rmotio n cueing . 5. 2 Building/Facilitie s Large rdom e siz e increase s th e Motio n envelope , takin g th e obstructio n fre e spac e require d t o highl yun practica l values . Highe rdrawbridg e acces s complicate s buildin g desig n an d emergenc yescap e system . Dom e Radiu s Require d Fre e Envelop e Longitudina l Latera l Vertica l Drawbridg e Acces s @ Settle d 3.25 m 13.7 m (44.9ft ) 13.2 m (43.3ft ) 11.0 m (36.1ft ) >4.0 m (13.1ft ) 4.25 m

15.7 m (51.2ft ) 15.2 m {49.9ft ) 12.5 m {41.0ft ) >5.0 m {16.5ft )
5. 3 Eye Strai n an d Ocuia rFatigu e Whe n focusin g a t a distanc e close rtha n Infinity , th e huma n ocula rsyste m react s throug h th e s o calle d accommodation-vergenc e refle xloop . I n a direc tprojectio n dom e scree n th e Imag e I s forme d a ta constan t distance , abou t th e dom e scree n radius , s o accommodatio n (chang e o fey e len s foca l length ) an d vergenc e (inwar d rotatio n o fth e eye s t o kee p th e projectio n o fth e Imag e i n th e cente ro fth e retina ) n o longe rcontribut e t o dept h perceptio n {whic h i s provide d i n th e simulato rb yothe rdifferen tmonocula r mechanisms , mostl yrelate d t o scen e conten tan d detail ) bu tpos e a ris k fo rey e strai n an d ocula rfatigu e becaus e o fth e involve d ey e muscle s bein g permanentl yunde rstress , th e close rth e objects , th e greate r th e strai n o n th e muscles .Ther e i s no t much literatur e o n dom e scree n vision , bu tther e i s extensiv e ergonomic s researc h availabl e

o n compute rworkstation s an d dat a visualizatio n displays , whic h ca n b e considere d essentiall ysimila rwit h regar d t o nea rvisio n fatigue
. I n accordanc e t o publishe d data , ey e strai n an d ocula rfatigu e develo p fo ra sustaine d visualizatio n tas k I fth e viewin g distanc e i s les s tha n th e restin g poin to faccommodatio n (RPA , defaul t accommodatio n distance , th e distanc e a twhic h th e eye s focu s i n tota l darkness , whe n ther e i s nothin g t o focu s on ) an d th e restlngpoin to fvergenc e (RPV , als o know n a s dar k vergence , th e distanc e a t whic h th e eye s ar e se t t o converg e whe n ther e i s n o objec tt o converg e on) , wit h th e stres s o n th e vergenc e syste m bein g th e dominan t facto rfo rvisio n strai n whil e shift s i n th e restin g poin to f accommodatio n ar e mor e relate d t o reductio n i n visua l acuit yo rkeennes s whe n switchin g t o vie wa distan t target . RP Aaverage s abou t 0.75 m (30in ) increasin g t o abou t1.0 m {40in ) wit h age . RP Vaverage s abou t1.15 m {45in ) fo rstraigh t view , comin g t o 0.90 m (35in) wit h a 30-degre e downwar d gaz e angle. So , dom e scree n radiuse s ar e i n bot h case s wel l beyon d th e viewin g distanc e require d no tt o develo p nea rvisio n fatigue , wit h th e large rdom e providin g n o clea radvantage . 6 Conclusion s Ther e I s n o on e singl e Visua l Displa ySyste m solutio n bein g optima l fro m al l point s o fvie wa tth e sam e time , s o i t shal l alway s b e a trade-of fcompromis e amon g regulator ycompliance , trainin g aspect s an d practica l simulato rdesig n considerations . Propose d VDS desig n provide s a n excellen tcoverag e o fEC175 cockpi tfield s o fvie wan d prett ygoo d heigh t perceptio n fo rgroun d operation s an d lo wleve l hover s an d fligh ttasks. Whil e i n stric tsense , 3.25 m (10.7ft ) dom e radiu s paralla xerro rfo rdistan tobject s I n cente rvie wi s ove rth e curren tg s requiremen tby 14CF R Par

t 60 , i t i s stil l kep t withi n practica l acceptabl e values , an d i n an ycase , vie wpoin tswitchin g allow s fo rpilot-flyin g erro rcancellatio n fo rcritica l fligh ttasks.