An investigation of separate surface stability augmentation systems for general aviation aircraft

APPENDIX A SSSA SYSTEM CHECK OUT SYSTEM FUNCTIONdL CIIECK PROCEDURES To o b t a i n m e a n i n g f u l d a t a d u r i n g f l i g h t t e s t i n g , i t i s m a n d a t o r y t h a t t h e SSSA s y s t e n i o p e r a t e i n a p r o p e r a n d c o n s i s t e n t m a n n e r . W h i l e c i r c u i t c h e c k p r o c e d u r e s o u t l i n e d i n t h e S y s t e m O p e r a t i o n 14anual ( R e f . 2 0 ) p r o v i d e a d e q u a t e c h e c k s o f c e r t a i n c o m p o n e n t s , t h i s s e c t i o n d e s c r i b e s f u n c t i o n a l c h e c k s t h a t may b e u s e d t o e x e r c i s e t h e e n t i r e SSSA s y s t e m . T h e s e c h e c k s a r e d i v i d e d i n t o t w o s u b s e c t i o n s : g r o u n d c h e c k s a n d f l i g h t c h e c k s . G r o u n d c h e c k s c o n f i r m c o r r e c t s y s t e m s e t u p a n d o p e r a t i o n o f t h e s l a v e a n d command m o d e s u s i n g t e s t s i g n a l s i n t r o d u c e d i n t o t h e s y s t e m . F l i g h t c h e c k s c o n f i r m p r o p e r o p e r a t i o n o f t h e command mode b y o b s e r v i n g a i r c r a f t r e s p o n s e t o c o n t r o l i n p u t s . T h e s e c h e c k s may b e u s e d o n a r o u t i n e b a s i s t o c o n f i r m c o n s i s t e n t s y s t e m o p e r a t i o n .

G r o u n d C h e c k s T h e s y s t e m g r o u n d c h e c k s e m p h a s i z e t h e SSSA c o n t r o l p o s i t i o n r e s u l t i n g f r o m a k n o w n i n p u t s i g n a l . T h e r e f o r e , t h e s e c h e c k s a r e s p e c i f i e d i n t e r m s o f a n g u l a r s u r f a c e p o s i t i o n , w h i c h may b e m e a s u r e d w i t h t h e a i d o f a s u r f a c e p o s i t i o n t e m p l a t e o r m o n i t o r e d e l e c t r i c a l l y f r o m t h e c a l i b r a t e d o u t p u t o f t h e c o r r e s p o n d i n g s u r f a c e p o s i t i o n p o t c n t i o r i i e t e r . I n p r e p a r a t i o n f o r g r o u n d c h e c k s , tlre SSSA c o m p u t e r c a r d s s h o u l d be a d j u s t e d f o r n o m i n a l g a i n s and f u n c t i o n a l l y t e s t e d a s d e s c r i b e d i n t h e Systern O p e r a t i o n Manual ( R e f . 2 0 ) . N e x t , t h e s y s t e m s h o u l d be a d j u s t e d f o r z e r o p o s i t i o n b o t h i n s l a v e and cor~~mand mode. T h i s i s a c c o m p l i s h e d by c e n t e r i n g t h e p i l o t c o n t r o l s ( z e r o d e f l e c t i o n p o s i t i o n ) , e n g a g i n g t h e SSSA s y s t e m , a n d c e n t e r i n g t h e SSSA c o n t r o l s u r f a c e s by a d j u s t i n g t h e " z e r o " o r " b i a s " p o t e n t i o m e t e r s on t h e a p p r o p r i a t e d r i v e c a r d . The l o c a t i o n o f t h e s e p o t e n t i o m e t e r s on t h e d r i v e c a r d s i s s p e c i f i e d i n R e f e r e n c e 2 0 . F i g u r e 9 . 1 shows t h e SSSA C o n t r o l a n d Management p a n e l and p o i n t s o u t m a j o r c o n t r o l s .

S l a v e Mode G a i n s I n a l l a x e s , t h e n o m i n a l v a l u e s of s l a v e g a i n s a r e = 1 . 0 . S l a v e g a i n s may be e a s i l y a d j u s t e d by K~~~~~ p o t e n t i o m e t e r s m o u nt e d on t h e s y s t e m o p e r a t o r ' s c o n s o l e .

S l a v e g a i n s may be c o n f i r m e d w i t h t h e f o l l o w i n g p r o c e d u r e : 1 . Engage and z e r o SSSA s y s t e m .

2 . I n t r o d u c e p i l o t c o n t r o l s u r f a c e d e f l e c t i o n o f known m a g n i t u d e .

3 . O b s e r v e c o r r e s p o n d i n g SSSA s u r f a c e p o s i t i o n ( F o r e x a m p l e : w i t h t h e e l e v a t o r s l a v e g a i n = 1 , a p i l o t e l e v a t o r d e f l e c t i o n o f +5" w i l l r e s u l t ' i n a SSSA e l e v a t o r d e f l e c t i o n o f + 5 O . ) B A D C E K & E FAULT POWER 0 ' . .

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A . S y s t e m P o w e r S w i t c h G . A c t u a t o r Mode S e l e c t B . S e r v o E r r o r I n d i c a t o r s S w i t c h C . S y s t e l n D i s e n g a g e L i g h t H . T r i m P o t e n t i o m e t e r s D . E n g a g e B u t t o n I. C i r c u i t B r e a k e r E . S u r f a c e P o s i t i o n I n d i c a t o r s J . H e a d i n g H o l d Mode F . A c t u a t o r D i s e n g a g e L i g h t S e l e c t S w i t c h F i g u r e 9 . 1 SSSA a n d i l a n g e n ~ e n t P a n e l -- -- I t s h o u l d b e c n ~ l ~ h a s i z e t l t h a t u n d c r a n o - l o a d c o n d i t i o n t h e s u r f a c e p o s i t i o n w i l l m a t c h t h e c o ~ l l n l a n d e d s u r f a c e p o s i t i o n . H o w e v e r , u n d e r l o a d ( a s i n f l i g h t ) t h e r e w i l l b e a n o f f s e t b e t w e e n t h e c o m n ~ a n d e d a n d a c t u a l s u r f a c e p o s i t i o n t h a t i s a f u n c t i o n o f t h e a c t u a t o r f e e d b a c k g a i n . T h e n a t u r e o f t h i s f u n c t i o n a l r e l a t i o n s h i p i s s h o w n i n F i g u r e 9 . 2 .

N o t i c e t h a t f o r a g i v e n l o a d i n g c o n d i t i o n t h e m a g n i t u d e o f t h e o f f s e t i s r e d u c e d b y i n c r e a s i n g t h e a c t u a t o r f e e d b a c k g a i n . H o w e v e r , i n c r e a s i n g t h i s g a i n t e n d s t o d e s t a b i l i z e t h e a c t u a t o r s e r v o l o o p . T h e r e f o r e , t h e a c t u a t o r f e e d b a c k S U R F A C E D E F L E C T I O N L I M I T ( A E R O D Y N A M I C H I N G E M O M E N T = M A X l MUM ACTUATOR MOM E N T ) NO- L O A D A C T U A L R E L A T I O N S H I P S U R F A C E A C T U A T O R FE E D B A C K G A I N COMMANDED S U R F A C E P O S l T l O N ( C O M M A N D V O L T A G E ) F i g u r e 9 . 2 E f f e c t o f -- A c t u a t o r F e e d b a c k G a i n g a i n s h o u l d be a d j u s t e d t o ' t h e h i g h e s t v a l u e t h a t d o e s n o t r e s u l t i n s u r f a c e o s c i l l a t i o n s . The s i m u l a t o r a c t u a t o r f e e d b a c k g a i n s a r e a p p r o x i m a t e l y 8 v o l t s / d c g r e e o f o f f s e t .

T h e s e v a l u e s may be r e a d j u s t e d f o r t h e f l i g h t t e s t h a r d w a r e . To o b t a i n t h e d e s i r e d s l a v e g a i n u n d e r f l i g h t l o a d s i t may be n e c e s s a r y t o i n c r e a s e t h e s l a v e g a i n s

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s l i g h t l y . F o r e x a m p l e , t o o b t a i n a s l a v e g a i n o f 1 . 0 i t may r e q u i r e s e t t i n g K S L A V E = 1 . 1 t o c o m p e n s a t e f o r o f f s e t a t t h e maximum a c h i e v a b l e v a l u e o f a c t u a t o r g a i n .

P i l o t D i s e n g a g e - The p i l o t may d i s e n g a g e t h e SSSA s y s t e m by t u r n i n g t h e s y s t e m power o f f ( c o m p u t e r a n d a l l a c t u a t o r s d i s e n g a g e ) , d e p r e s s i n g t h e c o n t r o l wheel mounted " k i l l " s w i t c h ( a c t u a t o r s d i s e n g a g e ) , o r by p l a c i n g t h e SSSA a x i s " o f f - s l a v e - c o m n l a n d " s w i t c h e s i n t h e " o f f " p o s i t i o n ( i n d i v i d u a l a c t u a t o r s d i s e n g a g e ) . T h e s e f e a t u r e s s h o u l d be c h e c k e d by e n g a g i n g t h e SSSA s y s t e m and e x e r c i s i n g e a c h d i s e n g a g e m e t h o d .

SSSA S u r f a c e L i m i t D i s c o n n e c t S w i t c h e s The SSSA c o n t r o l s y s t e m i n c l u d e s s u r f a c e p o s i t i o n l i m i t s w i t c h e s t o m i n i m i z e t h e c o n s e q u e n c e s o f h a r d - o v e r f a i l u r e s . I n t h e e v e n t a SSSA c o n t r o l s u r f a c e e x c e e d s i t s normal d e f l e c t i o n r a n g e , a s i n h a r d - o v e r f a i l u r e , t h e l i m i t s w i t c h w i l l d i s e n g a g e power fro111 t h e a f f e c t e d a c t u a t o r .

Aerodynatilic h i n g e olo~ncnts w i 11 t h e n t e n d t o r e t u r n t h e s u r f a c e t o t h e t r a i l p o s i t i o n a g a i n s t t h e f r i c t i o n o f t h e 3 3 u n p o w e r e d a c t u a t o r . P o w e r i s n o t r e a p p l i e d t o t h e a c t u a t o r u n l e s s t h e p i l o t e l e c t s t o d o s o fro111 t h e C o n t r o l a n d M a n a g e m e n t p a n e l .

P r o p e r o p e r a t i o n o f e a c h SSSA s u r f a c e l i m i t s w i t c h s h o u l d b e c h e c k e d u s i n g t h e f o l l o w i n g p r o c e d u r e : 1. E n g a g e t h e SSSA s y s t e m i n s l a v e m o d e .

2 . P o s i t i o n t h e S S S A s u r f a c e a t i t s d e f l e c t i o n l i m i t u s i n g t h e c o r r e s p o n d i n g p i l o t c o n t r o l .

3 . M a n u a l l y t r i p t h e s w i t c h o r f o r c e t h e s u r f a c e t o t r i p t h e l i m i t s w i t c h . T h e p o w e r r e l a y s h o u l d o p e n , r e m o v i n g p o w e r f r o m t h e a c t u a t o r .

4 . N o t e t h e s u r f a c e d e f l e c t i o n a t w h i c h t h e l i m i t s w i t c h a c t u a t e s . T h i s s h o u l d o c c u r a h e a d o f t h e s u r f a c e h a r d s t o p a n d s l i g h t l y b e y o n d t h e p i l o t s u r f a c e d e f l e c t i o n l i m i t .

SSSA S u r f a c e P o s i t i o n L i m i t T h e SSSA d r i v e c i r c u i t s i n c l u d e p r o v i s i o n t o l i m i t t h e m a x i m u l i ~ s u r f a c e d e f l e c t i o n command. T h i s f e a t u r e i s i n t e n d e d t o p r e v e n t t h e SSSA s u r f a c e s f r o m r e a c h i n g t h e l i m i t s w i t c h e s i n n o r m a l o p e r a t i o n a n d , t h e r e f o r e , m i n i m i z e n u i s a n c e a c t u a t o r d i s e n g a g e m e n t s . T h e p r o p e r o p e r a t i o n o f t h e p o s i t i o n l i m i t may b e o b s e r v e d b y i n j e c t i n g a n y command v o l t a g e t h a t w o u l d d r i v e t h e S S S A s u r f a c e p a s t i t s d e f l e c t i o n l i m i t . T h e f o l l o w i n g p r o c e d u r e i s b a s e d o n a s l a v e mode i n p u t : = 2 . 0 .

S e t % L A V E 2 . Engage and z e r o SSSA syste111 i n s l a v e mode.

3 . P o s i t i o n p i l o t s u r f a c e a t e a c h d e f l e c t i o n l i m i t .

4 . SSSA s u r f a c e p o s i t i o n s h o u l d a p p r o x i l n a t e l y a g r e e w i t h p i l o t s u r f a c e p o s i t i o n w i t h o u t t r i p p i n g t h e l i m i t d i s e n g a g e s w i t c h .

5 . R e t u r n K S L A V E t o n o m i n a l v a l u e .

C o n t r o l S u r f a c e P o s i t i o n I n d i c a t o r C a l i b r a t i s C o n t r o l s u r f a c e p o s i t i o n i n d i c a t o r s a r e i n s t a l l e d on t h e C o n t r o l and Management p a n e l t o a l l o w t h e p i l o t t o c o n t i n u o u s l y m o n i t o r SSSA and p i l o t c o n t r o l p o s i t i o n s .

C o r r e c t o p e r a t i o n a n d c a l i b r a t i o n of t h e s e i n d i c a t o r s may be o b s e r v e d by e n g a g i n g t h e s y s t e m i n s l a v e mode and c o m p a r i n g t h e a c t u a l s u r f a c e p o s i t i o n w i t h t h e p o s i t i o n i n d i c a t o r s t h r o u g h o u t t h e s u r f a c e d e f l e c t i o n r a n g e .

A u t o - T r i m T h r e s h o l d The a u t o - t r i m f e a t u r e o f t h e l o n g i t u d i n a l a x i s s e n s e s SSSA e l e v a t o r p o s i t i o n and d r i v e s t h e s t a b i l i z e r t h r o u g h t h e s e c o n d a r y s t a b i l i z e r m o t o r t o r e t u r n SSSA e l e v a t o r d e f l e c t i o n t o z e r o . To a v o i d a c t i v a t i n g a u t o - t r i m w i t h s h o r t t e r m SSSA e l e v a t o r d e f l e c t i o n s , a o n e s e c o n d l a g i s i n c o r p o r a t e d i n t h e s u r f a c e p o s i t i o n s e n s i n g c i r c u i t . The f o l l o w i n g p r o c e d u r e may be u s e d t o e x e r c i s e t h e a u t o - t r i m 1 . Engage t h e SSSA p i t c h a x i s i n co~ii~i~aritl 111ode wit11 t h e e l e v a t o r a c t u a t o r c i r c u i t b r e a k e r o p e n .

2 . With power a p p l i e d t o t h e s t a b i l i z e r m o t o r , m a n u a l l y d e f l e c t t h e SSSA e l e v a t o r beyond t h e 1 0 " t h r e s h o l d . A f t e r a p p r o x i l n a t e l y 1 s e c o n d , t h e s e c o n d a r y s t a b i l i z e r m o t o r s h o u l d b e g i n t o r u n i n t h e f o l l o w i n g d i r e c t i o n : SSSA E l e v a t o r D e f l e c t i o n S t a b i l i z e r Elotion T r a i l i n g e d g e u p L e a d i n g e d g e down T r a i l i n g e d g e down L e a d i n g e d g e u p 3 . R e t u r n t h e SSSA e l e v a t o r t o z e r o d e f l e c t i o n , t h a t i s , t r a i l p o s i t i o n w i t h r e s p e c t t o t h e s t a b i l i z e r The s t a b i l i z e r s h o u l d i n n i e d i a t e l y s t o p r u n n i n g .

Command Mode S t a t i c Checks The f e e d b a c k g a i n s o f t h e SSSA command mode may be c h e c k e d w i t h t h e e n t i r e s y s t e m i n s t a l l e d i n t h e a i r c r a f t .

To make t h e s t a t i c c h e c k a s i n c l u s i v e a s p o s s i b l e , t h e g a i n s a r e c h e c k e d from t h e g y r o o u t p u t t o t h e SSSA p o s i t i o n . The p i l o t c o n t r o l i n p u t i s i n t r o d u c e d by p o s i t i o n i n g t h e p i l o t s u r f a c e . Gyro i n p u t s a r e s i m u l a t e d by d i s c o n n e c t i n g t h e g y r o and i n j e c t i n g an a p p r o p r i a t e l y s c a l e d s i g n a l a t t h e g y r o m a t i n g e l e c t r i c a l c o n n e c t o r . The cornmand mode g a i n s a r e c h e c k e d u s i n g t h e f o l l o w i n g p r o c e d u r e : 1 . Engage and z e r o t h e SSSA s y s t e ~ l i i n command niode.

2 . I n t r o d u c e s c a l e d i n p u t s o n e a t a t i m e .

3 . M e a s u r e t h d r e s u l t i n g s t e a d y s t a t e SSSA s u r f a c e d e f l e c t i o n . T h e command mode g a i n i s t h e r a t i o o f s u r f a c e d e f l e c t i o n t o s c a l e d i n p u t .

T h e n o m i n a l v a l u e s o f command rnode g a i n s a r e s h o w n i n T a b l e 9 . 1 .

Command Mode D y n a m i c C h e c k s T h e p u r p o s e o f t h e d y n a m i c c h e c k s i s t o c o n f i r m t h a t t h e r e q u i r e d c o m p e n s a t i n g t r a n s f e r f u n c t i o n s a r e c o r r e c t l y m e c h a n i z e d o n t h e SSSA c o m p u t e r c a r d s . T h i s i s a c c o m p l i s h e d b y o b s e r v i n g t h e t r a n s f e r f u n c t i o n r e s p o n s e t o a s t e p i n p u t .

T h e d y n a m i c c h e c k may b e p e r f o r m e d w i t h t h e c i r c u i t c a r d s i n a t e s t b o x o r i n s t a l l e d i n t h e SSSA s y s t e m . T h e o u t p u t t o b e m o n i t o r e d i s t h e command v o l t a g e o u t p u t o f e a c h a x i s c o m p u t e r c a r d . F i g u r e s 9 . 3 , 9 . 4 , a n d 9 . 5 show t h e i n p u t s a n d i m p o r t a n t c h a r a c t e r i s t i c s o f t h e c o m p u t e r c a r d o u t p u t s .

G r o u n d T e s t E q u i p m e n t T a b l e 9 . 2 s u m m a r i z e s t e s t e q u i p m e n t t h a t w i l l b e r e q u i r e d f o r g r o u n d t e s t a n d s e t u p o f t h e SSSA s y s t e m .

T h o s e g r o u n d c h e c k s t h a t t a k e p l a c e i n t h e a i r c r a f t w i l l r e q u i r e t h e e n t i r e SSSA s y s t e m t o b e s u p p l i e d w i t h t h e n e c e s s a r y e l e c t r i c p o w e r (26VOC a n d 1 1 5 V 4 0 0 H Z A C ) . I n a d d i t i o n , p r o v i s i o n n ~ u s t b e 111adc t o s u p p l y e l e c t r i c p o w e r f o r t e s t e q u i p m e n t u s e d i n t h e a i r c r a f t o n l y d u r i n g g r o u n d t e s t s ( 1 1 5 V 6 0 t l Z A C ) . I t i s n o t a n t i c i p a t e d t h a t a n y S S S A s y s t e m d i a g n o s t i c e q u i p ~ ~ l c n t w i l l b e u s e d i n f l i g h t .

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TIME ( S E C ] Yaw T r a n s f e r F u n c t i o n S t e p R e s p o n s e F i g u r e 9 . 5

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F l i g h t C h e c k s The f l i g h t c h e c k s w e r e d e v e l o p e d t o p e r m i t r a p i d i n - f l i g h t e v a l u a t i o n o f t h e SSSA a t t i t u d e cornlnand f u n c t i o n P r o p e r s y s t e m o p e r a t i o n i s d e t e r m i n e d by o b s e r v a t i o n o f a i r c r a f t r e s p o n s e t o v a r i o u s p i l o t i n p u t s w i t h t h e SSSA s y s t e m e n g a g e d . I t s h o u l d be e m p h a s i z e d t h a t d u e t o t h e n a t u r e o f t h e i n p u t s and o b s e r v a t i o n s , t h e s e e v a l u a t i o n s a r e somewhat i m p r e c i s e and s u b j e c t i v e . The f l i g h t c h e c k s a r e b a s e d on an u n d e r s t a n d i n g o f t h e SSSA s y s t e m c a p a b i l i t i e s d e v e l o p e d d u r i n g f l i g h t s i m u l a t i o n . T h e r e f o r e , t h e s e c h e c k s s h o u l d r e p r e s e n t t h e b e s t SSSA s y s t e m o p e r a t i o n t o be e x p e c t e d d u r i n g f l i g h t t e s t . In a l l c a s e s , t h e f l i g h t T A B L E 9 . 1 COIIFIAEID I.IODE GAINS Comniand I n p u t R e s u l t i n g SSSA llode I n p u t M a g n i t u d e V o l t a g e S u r f a c e P o s i t i o n Gain R o l l A x i s : ( 2 +12 1 2 @ + l "/set 0 . 3 v P i t c h A x i s : ( 4 ) Yaw A x i s :

+5" - - + 5 O 1

& R P ( 5 + l / s e c 0 . 3 v ( 2 ) +1 0° 1 0 Y N O T E :

1 . Assuming v e r t i c a l g y r o r o l l s c a l i n g o f - + 9 0 ° = - +15v o r

0 . 1 6 7 v / d e g .

2 . Assuming r a t e g y r o s c a l i n g o f - + 5 0 ° / s e c = - +15v o r 0 . 3 v / d e a / s e c .

3 . ~ s s u m i n ~ v e r t i c a l g y r o p i t c h s c a l i n g of - +60° = - +15v o r o r 0 . 2 5 v / d e g .

4 . To o b s e r v e t h e s t e a d y s t a t e SSSA e l e v a t o r d e f l e c t i o n t h e e r r o r i n t e g r a t i o n i n t h e p i t c h a x i s colllputer c a r d 111ust be d i s a b l e d . R e f e r t o Syste111 O p e r a t i o n Manual ( R e f . 20 ) .

5 . To o b s e r v e 4 g a i n , t h e 1 . a s e c o n d washout ~ r l u s t be

d i s a b l e d . R e f e r t o System O p e r a t i o n Manual ( R e f . 2 0 ) .

TABLE 9 . 2 GROUND TEST EQUIPMENT D e s c r i p t i o n P u r p o s e o r U s e W h e r e U s e d 1 . O s c i l l o s c o p e , D u a l T r a c e F u n c t i o n a l C h e c k a n d G a i n S e t T e s t B e n c h ( H . P . 1 4 0 A o r E q u i v . ) o r SSSA C o m p u t e r C a r d s 2 . D i g i t a l M u l t i m e t e r SSSA C o m p u t e r C a r d a n d S y s t e m T e s t B e n c h a n d ( F l u k e 8OOOA o r E q u i v . ) C h e c k o u t A i r c r a f t ( G r o u n d ) I 3 . S i n e Wave S i g n a l SSSA C o m p u t e r C a r d T e s t T e s t B e n c h G e n e r a t o r I n p u t ( H . P . 209A o r E q u i v . ) C- t- 4 . D C P o w e r S u p p l i e s , - +15VDC, SSSA C o m p u t e r C a r d T e s t P o w e r T e s t B e n c h +26VDC S E P P ~ Y 5 . T e s t B o x w i t h M a t i n g S e t u p a n d C h e c k o f SSSA T e s t B e n c h C o n n e c t o r f o r SSSA C o m p u t e r C a r d s C o m p u t e r C a r d s 6 . D u p l i c a t e E l e c t r i c a l I n j e c t S i m u l a t e d G y r o S i g n a l s A i r c r a f t ( G r o u n d ) C o n n e c t o r f o r E a c h T y p e o f I n t o SSSA S y s t e m t o C h e c k a n d SSSA G y r o S e t Command Mode G a i n s 7 . DC S t e p I n p u t S o u r c e I n p u t f o r SSSA C o m p u t e r C a r d T e s t B e n c h ( P r e c i s e l y A d j u s t a b l e i n T r a n s f e r F u n c t i o n D y n a m i c C h e c k t h e R a n g e 0-1VDC) 8 . S t r i p C h a r t R e c o r d e r R e c o r d SSSA C o m p u t e r C a r d T e s t B e n c h T r a n s f e r F u n c t i o n S t e p R e s p o n s e 9. A i r c r a f t C o n t r o l S u r f a c e M e a s u r e S u r f a c e D e f l e c t i o n s D u r i n g A i r c r a f t ( G r o u n d ) ' D e f l e c t i o n I n d i c a t o r s G r o u n d C h e c k s c l l e c k s a r c b a s e d o n t h e r l o ~ ~ ~ i n a l f e e d b a c k g a i n s e s t a b l i s l ~ c d d u r i n g s t a t i c c h o c k s .

As p a r t o f t h e p r e f l i g h t c h e c k s , t h e f o l l o w i n g d i s e n g a g e m e n t c h e c k s s h o u l d b e a c c o m p l i s h e d : 1 . T u r n o n syste111 p o w e r a n d e n g a g e a l l a x e s o f t h e s y s t e m i n e i t h e r command o r s l a v e mode.

- 2 . I n s e q u e n c e , p l a c e e a c h a x i s mode s e l e c t s w i t c h i n t h e " o f f " p o s i t i o n . T h e s w i t c h e d a x i s s h o u l d d i s e n g a g e w h i l e t h e o t h e r a x e s r e m a i n e n g a g e d .

3 . W i t h a l l a x e s e n g a g e d , d e p r e s s t h e p i l o t c o n t r o l w h e e l m o u n t e d d i s e n g a g e s w i t c h . A l l a x e s s h o u l d d i s e n g a g e s i m u l t a n e o u s l y .

4 . W i t h a l l a x e s e n g a g e d , t u r n o f f s y s t e m p o w e r A l l a c t u a t o r s s h o u l d become u n p o w e r e d .

Yaw A x i s The SSSA y a w a x i s c o n s i s t s o f a d u t c h r o l l d a m p e r a n d a n o p t i o n a l h e a d i n g h o l d f e a t u r e m e c h a n i z e d t h r o u g h t h e SSSA r u d d e r . C o r r e c t o p e r a t i o n o f t h e yaw d a m p e r i s c o n f i r m e d b y e x c i t i n g t h e a i r c r a f t d u t c h r o l l a n d o b s e r v i n g t h e d a m p i n g o f t h e r e s u l t i n g o s c i l l a t i o n . Due t o t h e r e l a t i v e l y l a r g e r a t i o o f b a n k a n g l e t o s i d e s l i p , t h e SSSA r o l l a x i s i s a l s o e f f e c t i v e i n d a m p i n g d u t c h r o l l . T h e f o l l o w i n g p r o c e d u r e may b e u s e d t o c h e c k t h e yaw d a m p e r .

1 . T r i m t h e a i r c r a f t a t t h e d e s i r e d f l i g h t c o n d i t i o n .

2 . W i t h t h c SSSA s y s t c ~ ~ ~ e n g a g e d i n t l i c d e s i r e d c o n f i g u r a t i o n , d i s t u r b t h c a i r c r a f t u s i n g a p i l o t r u d d e r p u l s e o f a p p r o x i m a t e l y 5' m a g n i t u d e a n d 1 s e c o n d d u r a t i o n . D u t c h r o l l d a m p i n g w i l l b e d e g r a d e d i f t h e p i l o t r u d d e r i n p u t i s o f s u f f i c i e n t m a g n i t u d e t o r e s u l t i n SSSA r u d d e r - s a t u r a t i o n .

3 . W i t h p i l o t c o n t r o l s f i x e d , o b s e r v e t h e r e s u l t i n g a i r c r a f t o s c i l l a t i o n . The e x p e c t e d a i r c r a f t r e s p o n s e i s s u r i ~ m a r i z e d i n T a b l e 9 . 3 .

The l e v e l o f d u t c h r o l l d a m p i n g i s p r i m a r i l y a f f e c t e d b y t h e y a w r a t e f e e d b a c k g a i n K + .

The y a w a x i s h e a d i n g h o l d f e a t u r e a t t e m p t s t o m a i n t a i n t h e a i r c r a f t o n t h e commanded h e a d i n g b y d e f l e c t i n g t h e SSSA r u d d e r i n p r o p o r t i o n t o e r r o r f r o m t h e d e s i r e d h e a d i n g , a y .

E i t h e r " H e a d i n g H o l d " o r "Yaw Damper O n l y " mode o f t h e yaw a x i s i s s e l e c t e d b y a s w i t c h o n t h e C o n t r o l a n d M a n a g e m e n t p a n e l . T h i s s w i t c h i n g f u n c t i o n i s c h e c k e d b y o b s e r v i n g t h a t t h e S S S A r u d d e r a c t i v i t y c o r r e s p o n d s t o t h e s w i t c h p o s i t i o n When s e l e c t e d b y t h e c o n t r o l s w i t c h , h e a d i n g h o l d o p e r a t e s e i t h e r i n " t r a c k " o r " e n g a g e " mode a s c o n t r o l l e d b y l o g i c c i r c u i t r y . H e a d i n g h o l d r e v e r t s t o t h e t r a c k mode when t h e p i l o t w h e e l d e f l e c t i o n e x c e e d s a p r e s e t t h r e s h o l d . T h e n o n ~ i n a l t h r e s h o l d corresponds t o a p i l o t a i l e r o n d e f l e c t i o n o f - + 3 " . I l o w e v e r , t h i s t h r e s h o l d alay b c a d j u s t e d a s r e q u i r e d .

The h e a d i n g h o l d r c ~ l l a i n s i n t h e t r a c k node w h i l c t h e p i l o t 4 3 T A B L E 9.3 S S S A Y A W D A M P E R F L I G H T C H E C K A p p r o a c h F l i g h t C o n d i t i o n C r u i s e , F l i g h t C o n d i t i o n N u m b e r o f N u m b e r o f H e a d i n g D u t c h R o l l H e a d i n g S S S A R o l l D u t c h R o l l O v e r s h o o t s D a m p i n g R a t i o O v e r s h o o t s A x i s S t a t u s D a m p i n g R a t i o O f f t u r n s t h e a i r c r a f t t o a new h e a d i n g . While i n t h e t r a c k n ~ o d e , t h e SSSA r u d d e r a c t s a s a d u t c h r o l l d a ~ n p e r w i t h a 1 . D s e c o n d w a s h o u t . To e n g a g e t h e h e a d i n g h o l d , two c o n d i t i o n s m u s t be s a t i s f i e d : f i r s t , t h e p i l o t m u s t command w i n g s l e v e l f l i g h t by c e n t e r i n g h i s c o n t r o l w h e e l ; s e c o n d , t h e a i r c r a f t m u s t r e a c h l e v e l f l i g h t , d e f i n e d a s t h e c o n d i t i o n o f bank a n g r e l e s s t h a n a p r e s e t t h r e s h o l d . The nominal v a l u e o f bank a n g l e t h r e s h o l d i s 52". As soon a s b o t h e n g a g e m e n t c o n d i t i o n s a r e s a t i s f i e d , h e a d i n g hold w i l l a c c e p t t h e c u r r e n t a i r c r a f t h e a d i n g a s t h e r e f e r e n c e h e a d i n g .

The f o l l o w i n g p r o c e d u r e may be used t o c h e c k f o r c o r r e c t o p e r a t i o n of t h e h e a d i n g . hold f e a t u r e : 1 . With t h e wheel c e n t e r e d and a i r c r a f t w i n g s l e v e l on t h e d e s i r e d h e a d i n g , s e l e c t t h e yaw a x i s h e a d i n g h o l d mode.

2 . G e n e r a t e a h e a d i n g e r r o r by " s k i d d i n g " t h e a i r c r a f t w i t h t h e p i l o t r u d d e r . W i t h t h e p i l o t r u d d e r c e n t e r e d , t h e SSSA r u d d e r s h o u l d r e t u r n t h e a i r c r a f t t o w i t h i n 1 d e g r e e o f t h e p r e s e l e c t e d h e a d i n g .

3 . C r e a t e a s t e a d y s t a t e yawing niornent w i t h an a s y m m e t r i c power s e t t i n g . A t t h e nominal v a l u e o f K , , = 2 , t h e SSSA r u d d e r w i l l r e a c h j t s d e f l e c t i o n l i m i t f o r a h e a d i n g e r r o r of a p p r o x i n ~ a t e l y 7 " . L e s s t h a n 3 0 % of t h e t o t a l r u d d e r a r e a i s d e v o t e d t o t h e SSSA r u d d e r .

4 5 T h e r e f o r e , ' t h e SSSA r u d d e r a l o n e , d r i v e n by h e a d i n g h o l d , i s n o t c a p a b l e o f t r i m n ~ i n g a s e v e r e a s y m n ~ e t r i c t h r u s t c o n d i t i o n .

4 . U s i n g a c o n v e n t i o n a l banked t u r n , s e l e c t a new r e f e r e n c e h e a d i n g . P r o v i d e d t h e t u r n was i n i t i a t e d w i t h o u t a l a r g e h e a d i n g e r r o r , r e v e r s i o n t o t r a c k mode s h o u l d c r e a t e n o n o t i c e a b l e t r a n s i e n t a i r c r a f t m o t i o n s . C o n f i r m t h a t h e a d i n g h o l d h a s a c c e p t e d a new r e f e r e n c e h e a d i n g by r e p e a t i n g s t e p # 2 .

R o l l A x i s The SSSA r o l l a x i s p r o v i d e s bank a n g l e command and an o p t i o n a l r o l l a x i s h e a d i n g h o l d f u n c t i o n . A t t i t u d e command i s a c h i e v e d by d i s p l a c i n g t h e SSSA a i l e r o n s i n p r o p o r t i o n t o t h e e r r o r b e t w e e n bank a n g l e command ( p i l o t a i l e r o n p o s i t i o n ) and a i r c r a f t bank a n g l e . When a d i s t u r b a n c e r o l l i n g moment i s p r e s e n t , a s m i g h t r e s u l t f r o m a s y m m e t r i c f u e l l o a d i n g , t h e a i r c r a f t a t t a i n s a n e q u i l i b r i u m a t t i t u d e w h e r e t h e SSSA a i l e r o n moment, r e s u l t i n g f r o m t h e bank a n g l e e r r o r , b a l a n c e s t h e d i s t u r b a n c e o ~ o m e n t . The r e l a t i o n s h i p b e t w e e n t h e d i s t u r b a n c e and r e s u l t i n g bank a n g l e e r r o r i s t e r r l ~ e d t h e " s t i f f n e s s " o f t h e r o l l a x i s . The f o l l o w i n g p r o c e d u r e may be u s e d t o e v a l u a t e t h e r o l l s t i f f n e s s : 1 . T r i n ~ t h c a i r c r a f t f o r s t r a i g h t and l e v c l f l i g h t w i t h t h e r o l l a x i s conil~~arid mode engaged and t h e yaw a x i s s l a v e mode e n g a g e d .

2 . C r e a t e a s t e a d y s t a t e r o l l i n g moment t h r o u g h t h e a i r c r a f t r o l l - d u e - t o - s i d e s l i p c h a r a c t e r i s t i c by d i s p l a c i n g t h e p i l o t r u d d e r w i t h t h e p i l o t wheel - c e n t e r e d .

3 . O b s e r v e t h e r e s u l t i n g a i r c r a f t r o l l a t t i t u d e T a b l e 9 . 4 s u m m a r i z e s t h e r u d d e r i n p u t and e x p e c t e d bank a n g l e .

4 . C e n t e r t h e p i l o t r u d d e r . The a i r c r a f t s h o u l d r e t u r n t o l e v e l f l i g h t .

Bank a n g l e s t i f f n e s s i s p r i m a r i l y d e t e r m i n e d by t h e bank a n g l e f e e d b a c k g a i n , , K b .

T A B L E 9 . 4 R O L L AXIS STIFFNESS CHARACTERISTICS F l i g h t P i l o t Rudder R e s u l t i n g Bank A n g l e C o n d i t i o n D e f l e c t i o n D e v i a t i o n From Level Fl i g h t <

Approach Approx. 10" - 4 O

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C r u i s e Approx. 5 " - l o

The r a n g e o f bank a n g l e o v e r which a t t i t u d e command i s a v a i l a b l e i s d e t e r n ~ i n e d by t h e bank a n g l e a t which t h e SSSA a i l c r o n s r e a c h t h e i r d c f l c c t i o n l i m i t . A t bank a n g l e s beyond SSSA s a t u r a t i o n t h e a i r c r a f t r e s p o n d s a s a r a t e c o n t r o l r a t h e r t h a n a t t i t u d e c o n ~ ~ r ~ a ~ i d s y s t c ~ r ~ . S a t u r a t i o n a n d t h e g e a r i n g b e t w e e n b a n k a n g l e arid p i l o t a i l e r o n i n p u t i s p r i m a r i l y d e t e r m i n e d b y t h e r a t i o o f p i l o t i n p u t g a i n t o / K g . A t n o m i n a l g a i n s , e a c h b a n k a n g l e f e e d b a c k g a i n , K g A P d e g r e e o f p i l o t a i l e r o n i n p u t s h o u l d r e s u l t i n a p p r o x i m a t e l y 1 . 6 " o f b a n k a n g l e a n 2 s a t u r a t i o n s h o u l d o c c u r a t a b a n k a n g l e o f - + 3 0 ° .

The d a m p i n g o f t h e r o l l a x i s r e s p o n s e d e p e n d s , t o some e x t e n t , o n t h e m a g n i t u d e o f t h e command i n p u t . F o r s m a l l i n p u t s t h e r o l l a x i s r e m a i n s a l i n e a r s y s t e m , t h a t i s , t h e SSSA a i l e r o n s d o n o t r e a r h t h e i r d e f l e c t i o n l i r l i i t s d u r i n g t h e r e s p o n s e . T h e l i n e a r s t e p r e s p o n s e o f t h e r o l l a x i s r e s e m b l e s a f i r s t o r d e r s y s t e n ~ ( n o o v e r s h o o t ) v ~ i t h a t i m e c o n s t a n t o f a p p r o x i m a t e l y 0 . 7 s e c o n d s . F o r s t e p commands l a r g e e n o u g h t o s e n d t h e S S S A a i l e r o n s t o t h e i r d e f l e c t i o n l i m i t s b u t s m a l l e r t h a n 30°, t h e a i r c r a f t l t ~ i l l o v e r s h o o t t h e n r e t u r n t o t h e commanded b a n k a n g l e . F o r commands i n e x c e s s o f 30°, t h e a i r c r a f t r e s p o n d s a s a r a t e c o n t r o l l e d s y s t e m . D a m p i n g o f t h e r o l l a x i s i s p r i m a r i l y d e t e r n ~ i n e d b y t h e r o l l r a t e f e e d b a c k g a i n , K 4 .

T h e r o l l a x i s h e a d i n g h o l d f e a t u r e i s m e c h a n i z e d u s i n g t h e same l o g i c a n d h e a d i n g e r r o r c i r c u i t r y a s u s e d i n t h e y a w a x i s h e a d i n g h o l d . R o l l h e a d i n g h o l d e n t e r s t r a c k mode when t h e p i l o t a i l e r o n e x c c e d s a p r e s e t t h r e s h o l d a n d e n t e r s t h e e n g a g e mode when p i l o t a i l e r o n i s c e n t e r e d a n d 4 8 bank a n g l e e q u a l s z e r o . The n o ~ ~ l i n a l v a l u e s of t h r e s h o l d a r e t h e sanie a s t h e yaw a x i s v a l u e s : a i l e r o n t h r e s h o l d = 5 3 " and bank a n g l e t h r e s h o l d = - + 2 O .

N O T E : To f l y t h e r o l l a x i s h e a d i n g h o l d i t w i l l be n e c e s s a r y t o i n s u r e t h a t t h e yaw a x i s h e a d i n g h o l d h a s been d i s a b l e d .

The o p e r a t i o n o f t h e r o l l h e a d i n g h o l d i s s i m i l a r t o t h e a n a l o g o u s yaw a x i s s y s t e m . A bank a n g l e r e f e r e n c e s i g n a l p r o p o r t i o n a l t o h e a d i n g a n g l e e r r o r , A Y , d r i v e s t h e SSSA a i l e r o n s . The a i r c r a f t t h e n b a n k s t o t u r n t h e a i r c r a f t t o w a r d t h e d e s i r e d h e a d i n g . A 1 i m i t e r i s p r o v i d e d t o p r e v e n t h e a d i n g h o l d f r o m commanding a bank a n g l e i n e x c e s s of 15' r e g a r d l e s s o f t h e m a g n i t u d e of A Y . The h e a d i n g h o l d c h e c k p r o c e d u r e o u t l i n e d i n t h e yaw a x i s s e c t i o n i s r e p e a t e d i n a f o r m t h a t a p p l i e s t o t h e r o l l a x i s m e c h a n i z a t i o n : 1 . W i t h t h e wheel c e n t e r e d and a i r c r a f t w i n g s l e v e l on t h e d e s i r e d h e a d i n g , s e l e c t t h e r o l l a x i s h e a d i n g h o l d mode.

2 . G e n e r a t e a h e a d i n g e r r o r by " s k i d d i n g " t h e a i r c r a f t w i t h t h e p i l o t r u d d e r . W i t h t h e p i l o t r u d d e r c e n t e r e d , t h e SSSA a i l e r o n s s h o u l d t u r n t h e a i r c r a f t t o w i t h i n 1 d e g r e e o f t h e p r e s c l c c t e d h e a d i n g . F o r t h e n o m i n a l v a l u e of = 0 . 5 5 d e g a i l . / d e g A Y t h e a i r c r a f t s h o u l d

K Y

r e t u r n t o t h e conl~nanded h e a d i n g w i t h no rltore t h a n 1 o v e r s h o o t .

3 . C r e a t c a s t e a d y s t a t c y a w i n g n ~ o ~ ~ l e n t w i t h a n a s y m ~ ~ ~ c t r i c p o w e r s e t t i n g . T h e a i r c r a f t w i l l b a n k t o w a r d t h c d e s i r e d h e a d i n g a n d s t a b i l i z e a t a s t e a d y s t a t e b a n k a n g l e . A t n o t i m e s h o u l d t h e r o l l a x i s h e a d i n g h o l d command a b a n k a n g l e i n e x c e s s o f 1 5 " .

4 . U s i n g a c o n v e n t i o n a l b a n k e d t u r n , s e l e c t a new a i r c r a f t r e f e r e n c e h e a d i n g . T h e r e v e r s i o n t o t r a c k mode s h o u l d n o t c r e a t e a n y n o t i c e a b l e t r a n s i e n t m o t i o n . C o n f i r m t h a t h e a d i n g h o l d h a s a c c e p t e d a new r e f e r e n c e h e a d i n g b y r e p e a t i n g s t e p # 2 .

P i t c h A x i s The SSSA p i t c h a x i s p r o v i d e s a t t i t u d e command by d r i v i n g t h e SSSA e l e v a t o r t o m a i n t a i n t h e a i r c r a f t p i t c h a n g l e i n f i x e d p r o p o r t i o n t o t h e p i l o t e l e v a t o r ( c o n t r o l c o l u m n ) p o s i t i o n . An " a u t o - t r i m " o r " s t a b i l i z e r f o l l o ; ~ u p ' ' m i n i m i z e s t h e e f f e c t s o f a n SSSA e l c v a t o r d i s c o n n e c t a n d i n c r e a s e s p i t c h a u t h o r i t y b y m a i n t a i n i n g i t s d e f l e c t i o n n e a r z e r o . I n a d d i t i o n , t h e SSSA p i t c h a x i s i n c l u d e s a f o r w a r d l o o p i n t e g r a t i o n t h a t d r i v e s l o n g t e r m e r r o r s i n p i t c h a t t i t u d e t o z e r o . T h e i . l o d e l 9 9 l o n g i t u d i n a l e l e c t r i c trim h a s b e e n i n c o r p o r a t e d i n t o t h e p i t c h a t t i t u d e c o m n ~ a n d s y s t e m t o a l . l o w p i t c h a t t i t u d e command t h r o u g h t h e p i l o t c o l u n ~ n , trill1 b u t t o n , o r c o l ~ l b i n a t i o n o f t i l e t w o . T h e f o l l o w i n g p r o c e d u r e s inay b e u s e d t o e v a l u a t e e a c h f u n c t i o n o f t h e p i t c h a x i s : SSSA P I T C H A X I S 1 . W i t h t h e a i r c r a f t t r i m m e d f o r s t r a i g h t a n d l e v e l f l i g h t , e n g a g e t h e SSSA p i t c h a x i s i n command mode.

2 . Command a new p i t c h a t t i t u d e u s i n g t h e p i l o t e l e v a t o r ( c o l u m n ) . T h e r e l a t i o n s h i p b e t w e e n p i t c h a t t i t u d e c h a n g e a n d p i l o t e l e v a t o r i n p u t

s h o u l d b e 0 . 6 d e g A e / d e g 6 . T h i s g e a r i n g i s

P a f u n c t i o n o f t h e r a t i o o f p i l o t i n p u t g a i n t o 3 . I n r e s p o n s e t o a s t e p p i l o t e l e v a t o r i n p u t t h e a i r c r a f t s h o u l d s t a b i l i z e a t t h e commanded a t t i t u d e w i t h n o m o r e t h a n o n e o v e r s h o o t o f l e s s t h a n 1 0 % . T h e d a m p i n g o f t h e p i t c h r e s p o n s e i s p r i m a r i l y d e t e r m i n e d b y t h e r a t i o o f p i t c h r a t e t o p i t c h a n g l e f e e i b a c k g a i n s , K i / K e .

I n d u c e a c h a n g e i n a i r c r a f t p i t c h i n g moment b y 4 .

d e f l e c t i n g t h e f l a p s a n d m a i n t a i n c o n s t a n t a i r s p e e d w i t h p o w e r s e t t i n g . T h e f o r w a r d l o o p i n t e g r a t i o n s h o u l d r e t u r n t h e a i r c r a f t t o t h e commanded a t t i t u d e w i t h no n o t i c e a b l e o f f s e t o r e r r o r w i t h i n . 3 s e c o n d s .

5 . Command a c h a n g e i n a t t i t u d e u s i n g t h e p i l o t e l e v a t o r , a n d t h e n b y u s i n g t h e p i l o t t r i m .

F i n a l l y , e s t a b l i s h a n a t t i t u d e w i t h t h e e l e v a t o r a n d t r i m t h e s t i c k f o r c e t o z e r o u s i n g t h e p i l o t t r i m . I t s h o u l d b e p o s s i b l e t o e s t a b l i s h a d e s i r e d a t t i t u d e u s i n g a n y o f t h e s e m e t h o d s .

AUTO-TRIM 1 . W i t h p i t c h command mode e n g a g e d a n d t h e a i r c r a f t t r i m m e d f o r l e v e l f l i g h t , m a k e s p e e d c h a n g e s w i t h t h r o t t l e s e t t i n g . P i t c h a n g l e s h o u l d n e v e r v a r y f r o m commanded a t t i t u d e m o r e t h a n 2 " .

2 . As a i r s p e e d c h a n g e s , t h e S S S A e l e v a t o r s h o u l d d e f l e c t t o m a i n t a i n a t t i t u d e . When e l e v a t o r d e f l e c t i o n e x c e e d s t h e a u t o - t r i m t h r e s h o l d ( n o m i n a l v a l u e o f 1 0 ' ) t h e s t a b i l i z e r s h o u l d d r i v e i n t h e a p p r o p r i a t e d i r e c t i o n t o r e d u c e SSSA e l e v a t o r d e f l e c t i o n t o z e r o . C h e c k i n b o t h a i r c r a f t n o s e u p ( s p e e d d e c r e a s i n g ) a n d a i r c r a f t n o s e d o w n ( s p e e d i n c r e a s i n g ) d i r e c t i o n s .

3 . ,Make c o n f i g u r a t i o n c h a n g e s w i t h l a n d i n g g e a r a n d f l a p s . T h e p i t c h a x i s w i t h a u t o - t r i m s h o u l d m a i n t a i n t h e a i r c r a f t w i t h i n - + 2 " o f t h e c o ~ n n l a n d e d a t t i t u d e . S i m u l a t o r e v a l u a t i o n s i n d i c a t e t h a t t h e a u t o - t r i m r a t e may b e m a r g i n a l f o r t h e l a n d i n g w a v e - o f f c a s e .

4 . W i t h a u t o - t r i m r u n n i n g , o p p o s e w i t h t h e p i l o t trim b u t t o n . T h e p i l o t t r i m s h o u l d o v e r - r i d e t h e a u t o - t r i m i n b o t h d i r e c t i o n s .

5 . W i t h a u t o - t r i m r u n n i n g , d e p r e s s t h e p i l o t d i s e n g a g e b u t t o n . A u t o - t r i m s h o u l d s t o p r u n n i n g .

6 . When a u t o - t r i m r u n s t h e a i r c r a f t a t t i t u d e s h o u l d n o t c h a n g e u n l e s s commanded t h r o u g h t h e p i l o t t r i m o r e l e v a t o r .

T h r o u g h o u t t h e s e f l i g h t c h e c k s r e f e r e n c e h a s b e e n made t o t h e e x p e c t e d p e r f o r m a n c e o f t h e s y s t e m b a s e d o n n o m i n a l g a i n s a n d a d j u s t m e n t s . T h e s e a d j u s t m e n t s a n d g a i n s s h o u l d b e s u i t a b l e f o r f l i g h t t e s t i n g ; t h e r e f o r e , t h e r e s h o u l d b e n o n e e d o f a n e x t e n s i v e g a i n t a i l o r i n g p r o g r a m d u r i n g f l i g h t t e s t . I t w i l l b e l e f t t o t h e j u d g m e n t o f t h e f l i g h t t e s t p r o j e c t p i l o t a n d e n g i n e e r t o d e t e r m i n e i f t h e a c t u a l s y s t e m p e r f o r m a n c e i s s i g n i f i c a n t l y d e g r a d e d f r o m t h e e x p e c t e d p e r f o r m a n c e . I n t h e e v e n t t h a t i t i s n e c e s s a r y t o m o d i f y some g a i n s b a s e d o n f l i g h t t e s t e x p e r i e n c e , C h a p t e r 7 o f t h i s d o c u m e n t e x p l a i n s t h e i n t e r r e l a t i o n s h i p o f t h e g a i n s a n d s h o u l d p r o v e h e l p f u l .

APPENDIX B QUALITATIVE FLIGHT TEST PLAN This appendix r e p r e s e n t s a " f i r s t cut" a t t h e problem of d e f i n i n g t h e q u a l i t a t i v e f l i g h t t e s t p l a n . It w i l l be f u r t h e r managed and coordinated with Beech and w i t h NASA.

A d e t a i l e d q u a n t i t a t i v e f l i g h t t e s t p l a n w i l l be developed i n t h e n e a r f u t u r e . T h i s w i l l c o n t a i n d a t a processing flow c h a r t s .

SSSA QUALITATIVE FLIGHT ANALYSIS General Discussion of P r i n c i p l e s An i n t e g r a l p a r t of t h e SSSA program i s t h e a n a l y s i s of t h e f l i g h t hardware o r t h e f l i g h t e v a l u a t i o n . A t t h e p r e s e n t time t h i s program is broken down i n t o two phases, t h e 1 ) q u a n t i t a t i v e a n a l y s i s , 2 ) q u a l i - t a t i v e a n a l y s i s .

The q u a n t i t a t i v e a n a l y s i s w i l l be t h e comparison of a b s o l u t e per- formance maneuvers between t h e s t a n d a r d model 99 and t h e SSSA modified model 9 9 . The q u a l i t a t i v e a n a l y s i s , however, i s n ' t q u i t e a s d e f i n i t a - t i v e a s t h e q u a n t i t a t i v e a n a l y s i s due t o t h e f a c t t h a t t h e d a t a generated a r e p i l o t opinions. T h i s t y p e of an a n a l y s i s i s n ' t a s "cut-and-dried" a s a p l o t of s t i c k f o r c e v e r s u s speed o r s t i c k f o r c e v e r s u s g o r r o l l response, e t c . However, i t i s one of t h e most important i n g r e d i e n t s i n developing a v i a b l e system. Therefore, c o n s i d e r a b l e a t t e n t i o n must be given t o e s t a b l i s h i n g t h e e v a l u a t i o n c r i t e r i o n and r e l a t i n g t h i s c r i t e r i o n t o some known s t a n d a r d .

The s t a n d a r d used i n most i n s t a n c e s i s t h e "Cooper-Harper" s c o r e of p i l o t r a t i n g , ( s e e Fig. 1 and 2 ). T h i s s c a l e i s an attempt t o s t a n d a r d i z e t h e b a s i s upon which p i l o t s would r a t e a i r p l a n e handling q u a l i t i e s . For example, i f an a i r c r a f t was r a t e d an c v e r a l l 3 . 0 , then everyone would know, whether t h e y had flown t h e a i r c r a f t o r n o t , t h a t f o r t h e mission d e f i n e d i t had r e l a t i v e l y good handling q u a l i t i e s .

It h a s some "mildly unpleasant" c h a r a c t e r i s t i c s but i t i s s t i l l i n t h e upper p o r t i o n of t h e r a t i n g s c a l e . Thc important p o i n t t o remember i s PERFORMANCE The measure of a d d i t i o n a l p i l o t e f f o r t The p r e c i s i o n of c o n t r o l with r e s p e c t t o and a t t e n t i o n r e q u i r e d t o maintain a a i r c r a f t movement t h a t a p i l o t i s a b l e t o given l e v e l of performance i n t h e f a c e achieve i n performing a t a s k . ( P i l o t - v e h i c l e p e r f o n a n c e i s a measure of handl- of d e f i c i e n t v e h i c l e c h a r a c t e r i s t i c s .

i n g performance. P i l o t performance i s a measure of t h e manner o r e f f i c i e n c y with HANDLING QUALITIES which a p i l o t moves t h e p r i n c i p a l c o n t r o l s i n p e r f o n i n g a t a s k . ) Those q u a l i t i e s or c h a r a c t e r i s t i c s of an a i r c r a f t t h a t govern t h e e a s e and p r e c i - s i o n w i t h which a p i l o t i s a b l e t o perform ROLE

-

t h e t a s k s r e q u i r e d i n support of an a i r - The f u n c t i o n o r purpose t h a t d e f i n e s t h e c r a f t r o l e .

primary use of an a i r c r a f t .

MISSION TASK

-

The composite of p i l o t - v e h i c l e f u n c t i o n s The a c t u a l work assigned a p i l o t t o be t h a t must be performed t o f u l f i l l opera- t i o n a l requirements. May be s p e c i f i e d performed i n completion of or a s r e p r e - s e n t a t i v e of a d e s i g n a t e d f l i g h t segment.

f o r a r o l e , complete f l i g h t , f l i g h t phase, o r f l i g h t subphase.

W O R K L O A D The i n t e g r a t e d p h y s i c a l and mental e f f o r t r e q u i r e d t o perform a s p e c i f i e d p i l o t i n g t a s k .

F i g u r e 1. D e f i n i t i o n s From TN-D-5153 AIRCRAFT DalANDS ON THE PILOT PILOT JDEQUACY FOR SELECTED TASK OR CHARACTERISTICS IN SELECTED TASK OR REQUIRED OPERATION* RATING REQUIRED OPERATION* P i l o t c o m p e n s a t i o n n o t a f a c t o r E x c e l l e n t H i g h l y d e s i r a b l e f o r d e s i r e d p e r f o r m a n c e Good P i l o t c o m p e n s a t i o n n o t a f a c t o r N e g l i g i b l e f o r d e s i r e d p e r f o r m a n c e 2 d, Minimal p i l o t c o m p e n s a t i o n r e q u i r e d Fa ir--Some m i l d l y u n p l e a s a n t f o r d e s i r e d p e r f o r m a n c e D e s i r e d p e r f o r m a n c e r e q u i r e s Minor b u t a n n o y i n g s h o r t c o m i n g s m o d e r a t e p i l o t c o m p e n s a t i o n S h o r t - ? l o d e r a t e l y o b j e c t i o n a b l e Adequate p e r f o r m a n c e r e q u i r e s c o n s i d e r a b l e p i l o t c o m p e n s a t i o n s h o r t c o m i n g s Improvement Very o b j e c t i o n a b l e b u t Adequate p e r f o r m a n c e r e q u i r e s t o l e r a b l e s h o r t c o m i n g s . e x t e n s i v e p i l o t c o m p e n s a t i o n D e s i r e d V, -4 Adequate p e r f o r m a n c e n o t a t t a i n a b l e w i t h maximum t o l e r a b l e p i l o t compen- Major d e f i c i e n c i e s s a t i o n . C o n t r o l l a b i l i t y n o t i n D e f i c i e n c i e s q u e s t i o n .

C o n s i d e r a b l e p i l o t c o m p e n s a t i o n i s Major d e f i c i e n c i e s r e q u i r e d f o r c o n t r o l I n t e n s e p i l o t c o m p e n s a t i o n i s Major d e f i c i e n c i e s 9 r e q u i r e d t o r e t a i n c o n t r o l I C o n t r o l w i l l b e l o s t d u r i n g some m a n d a t o r y Major d e f i c i e n c i e s p o r t i o n o f r e q u i r e d o p e r a t i o n 1 0

*

D e f i n i t i o n o f r e q u i r e d o p e r a t i o n i n v o l v e s P i l o t d e c i s i o n s d e s i g n a t i o n o f f l i g h t p h a s e a n d / o r s u b p h a s e s w i t h accompanying c o n d i t i o n s .

F i g u r e 2 . H a n d l i n g Q u a l i t i e s R a t i n g S c a l e Based upon Cooper-llnrper Handling O u a l i t i e s R a t i n g S c a l e (Ref NASA TN-11-5153) t h a t t h i s s c a l e a t t e m p t s t o a l l e v i a t e t h e p e r s o n a l p r e f e r e n c e s of t h e p i l o t s and t h a t when a r a t i n g is generated it w i l l apply t o a g e n e r a l c r o s s s e c t i o n of p i l o t s . T h i s s t a n d a r d i z a t i o n i s accomplished by two methods, 1 ) impressing on t h e e v a l u a t i o n p i l o t t o r e p o r t e x a c t l y what he s e e s and n o t t r y t o a n a l y z e t h e s i t u a t i o n too deeply, 2 ) by having an engineer who can v e r y s y s t e m a t i c a l l y apply a l l of t h e l o g i c a l s t e p s of t h e "Cooper-Harper'' s c a l e i n g e n e r a t i n g an a b s o l u t e number f o r a p i l o t r a t i n g . T h i s w i l l r e q u i r e t h e engineer t o be lcnowledgeable of t h e f l i g h t t a s k and mission such t h a t p e r t i n e n t q u e s t i o n s can be asked t h a t w i l l s t i m u l a t e t h e p i l o t t o j u s t i f y o r defend h i s e v a l u a t i o n com- ments.

A p p l i c a t i o n of t h e s e p r i n c i p l e s t o t h e SSSA f l i g h t program should f o l l o w t h r e e l o g i c a l s t e p s : 1. Define t h e mission of t h e a i r c r a f t .

2 . Define t h e t a s k involved i n t h a t mission.

3 . Define t h e f i e l d of p i l o t s t h a t i s a p p l i c a b l e t o t h e mission.

Evaluation C r i t e r i o n 1. Define t h e mission of t h e a i r c r a f t .

The g e n e r a l mission of t h e b a s i c a i r c r a f t i s t r a n s p o r t i n g people However, t h e primary g o a l of t h i s program i s from p o i n t A t o p o i n t B.

t o determine whether o r not theAACCSsystem improves t h e handling charac- t e r i s t i c s of t h i s c l a s s of a i r p l a n e . T h e r e f o r e , i t w i l l be n e c e s s a r y t o d e f i n e t h e p i l o t r a t i n g of t h e s t a n d a r d model 99 such t h a t any improvements o r d e g r a d a t i o n s i n t h e p i l o t r a t i n g s can be d e t e c t e d on t h e modified a i r c r a f t . These d a t a w i l l be generated w i t h i n t h e c o n f i n e s of t h e g e n e r a l mission of t h e b a s i c a i r p l a n e . T h i s t y p e of a n a l y s i s w i l l a l s o e s t a b l i s h t h e f e a s i b i l i t y of t h e SSSA system when mechanized a s an a t t i t u d e command c o n t r o l system.

2. Define t h e t a s k involved i n t h a t mission.

The b a s i c t a s k involved i n t h e g e n e r a l mission i s an IFR p r o f i l e c o n s i s t i n g of a r e l a t i v e l y low a l t i t u d e c r u i s e , d e s c e n t o r p e n e t r a t i o n t o a f i n a l approach course, approach t o landing and a missed approach o r go-around. Therefore, t o e v a l u a t e a l l phases of t h i s p r o f i l e s e v e r a l maneuvers have been developed which tend t o r e p r e s e n t t h e t a s k of heading c o n t r o l , c o n s t a n t r a t e climbs and d e s c e n t s , s t e a d y r a t e t u r n s , course and g l i d e s l o p e i n t e r c e p t i o n s .

A . V e r t i c a l S Maneuver -- This maneuver i s designed t o develop

t h e p i l o t ' s instrument c r o s s check and a i r c r a f t c o n t r o l under instrument The maneuver c o n s i s t s of a c o n s t a n t r a t e climb, f l i g h t c o n d i t i o n s .

500 fpm, f o r 500 f t , while m a i n t a i n i n g a c o n s t a n t a i r s p e e d , 100 k i a s , and a standard r a t e t u r n . A t t h e end of t h e 500 f t climb t h e t u r n i s reversed and a 500 f t descent i s s t a r t e d a t a c o n s t a n t r a t e of 500 fpm and c o n s t a n t a i r s p e e d , 100 k i a s , ( s e e F i g . 3 ) . T h i s t y p e of V e r t i c a l S can be repeated f o r a s many c y c l e s a s d e s i r e d . T h i s maneuver w i l l tend t o u t i l i z e many of t h e design f e a t u r e s of t h e SSSA system; e l i m i n a t i o n of t r i m changes with power, u n d e s i r a b l e s p i r a l i n s t a b i l i t i e s and p r e c i s e climb and descent c o n t r o l .

The d a t a r e q u i r e d f o r t h i s maneuver a n d t h e e v a l u a t i o n c r i t e r i a f o r those parameters a r e a s follows: Evaluation C r i t e r i a Parameter 1. A l t i t u d e A l l of t h e s e parameters w i l l be 2. P i t c h Angle, 0 evaluated by looking a t e x c u r s i o n s from t h e defined c o n s t a n t s , R I C , A/S, t r a n s i t i o n a l t i t u d e s , e t c .

5. C o n t r o l T r a v e l s , ( P i l o t & SSSA)

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6. TIM 7 . P i l o t Comments Configuration -- g e a r dn, f l a p s approach, A / s = 100 k i a s , R/C=R/D=500 fpm, @ = Std. Rate Turn, Alt.=500 f t .

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The d a t a taken f o r comparison must be compared a t approximately t h e same l e v e l of t u r b u l e n c e . Therefore, t h e s e d a t a w i l l be r e q u i r e d f o r d e f i n i t i o n of t h e t e s t c o n d i t i o n s .

B. ILS Approach -- To emphasize t h e performance c h a r a c t e r i s t i c s

of t h e e v a l u a t i o n a i r c r a f t t h e ILS approaches w i l l not be flown a s I n s t e a d i t w i l l be flown w i t h two v a r i a - conventional I L S approaches.

t i o n s , 1) t h e modified l o c a l i z e r i n t e r c e & i o n and 2 ) t h e modified g l i d e - s l o p e i n t e r c e p t i o n .

The modified l o c a l i z e r i n t e r c e p t i o n w i l l c o n s i s t of c o n f i g u r i n g t h e a i r c r a f t , gear down, f l a p s approach, A / S = 100 kiafi a t t h e g l i d e s l o p e intercept angle, within interception altitude, with a 90' localizer the localizer needle 1 mile outbound of the outer marker. As soon as the pilot will attempt to maneuver the aircraft onto begins to move,the the localizer and glidepath localizer such that he is established on Fig. 3).

when he reaches the outer marker, (see will force the pilot to overshoot the This exaggerated intercept which will readily tax the localizer and result in rapid maneuvering capabilities of the lateral control. Therefore, any operational improvement or degradation of the flight controls should be readily observed.

the same intent as the The modified glideslope interception has modified localizer interception; exaggerating the maneuvering require- ments for the approach. However, this is aimed at the longitudinal trim characteristics of the aircraft. This maneuver is begun by estab- outbound of the outer marker at lishing the aircraft on the localizer an altitude 500 ft above the glideslope interception altitude. The will be clean, gear and flaps up, airspeed 120 kias.

aircraft configuration When the aircraft reaches the outer marker the pilot will attempt, as quickly as possible, to configure the aircraft into the approach config- descend and intercept the ILS glideslope.

uration, This maneuver will tend to exaggerate the trim requirements with gear and flap extensions and power applications. In addition it will also emphasize the importance of good descent and heading control.

This altitude may vary depending upon degree of pilot work load.

The d a t a r e q u i r e d f o r t h e 1.ocalizer and g l i d e s l o p e t a s k a r e a s follows: LOCALIZER TASK Evaluation C r i t e r i a Parameter 1. A/S 2 . ALT Looking f o r mean d e v i a t i o n s from 3 . Bank Angle, @ t h e known v a l u e s such a s g l i d e s l o p e

4 . p i t c h Angle, e

and l o c a l i z e r , Also v a r i a t i o n of 5. Heading Angle, '?

c o n t r o l f o r c e s and t r a v e l s .

6. Control Travel (SSSA & P i l o t ) 7 . L o c a l i z e r P o s i t i o n 8. Glideslope P o s i t i o n 9 . Control Forces 10. TI1.I 11. P i l o t Comments

Configuration -- gear down, f l a p s approach, A/S = 100 k i a s , A l t . = g l i d e -

s l o p e i n t e r c e p t i o n a l t i t u d e .

GLIDESLOPE TASK Evaluation C r i t e r i a Parameters 1. A/S 2 . ALT 3 . Bank Angle, $ I Looking f o r mean d e v i a t i o n s from 4 . P i t c h Angle, 0 t h e known v a l u e s such a s g l i d e s l o p e 5. Heading Angle, Y and l o c a l i z e r . Also v a r i a t i o n of 6. C o n t r o l T r a v e l s (SSSA & P i l o t ) c o n t r o l f o r c e s and t r a v e l s .

7 . L o c a l i z e r P o s i t i o n 8. G l i d e s l o p e P o s i t i o n 9. C o n t r o l F o r c e s 10. G l i d e P o s i t i o n 11. F l a p P o s i t i o n 1 2 . T h r o t t l e P o s i t i o n 1 3 . TIM 1 4 . P i l o t Comments Configuration -- p r i o r t o OM: gear up, f l a p s up, a l t i t u d e 500 f t above a s i n t e r c e p t a l t i t u d e a i r s p e e d , 120 k i a s .

inbound from OM: gear down, f l a p s approach, e s t a b l i s h e d on g l i d e s l o p e & l o c a l i z e r , a i r s p e e d = 100 k i a s .

C . Go-Around -- T h i s maneuver i s m e r e l y t o d e m o n s t r a t e t h e e f f e c t s o f t h e SSSA s y s t e m on t h e b a l k e d l a n d i n g o r go-around c o n d i t i o n s . The maneuver s h o u l d b e f l o w n from t h e ILS m i s s e d a p p r o a c h p o i n t w i t h t h e a i r c r a f t c o n f i g u r e d f o r l a n d i n g , g e a r down, f l a p s l a n d i n g , A/S = 1 0 0 k i a s .

When t h e a i r c r a f t r e a c h e s t h e m i s s e d a p p r o a c h a l t i t u d e t h e p i l o t w i l l a p p l y f u l l power, b e g i n a c l i m b and r a i s e t h e g e a r and f l a p s a s p r e s c r i b e d i n t h e f l i g h t manual.

The d a t a r e q u i r e d f o r t h i s maneuver w i l l b e a s f o l l o w s : P a r a m e t e r E v a l u a t i o n C r i t e r i a 1. AIS V a r i a t i o n 2 . A l t . V a r i a t i o n a f t e r e x e c u t i o n o f go-around 3 . Bank Angle, I $ V a r i a t i o n & max.

4. P i t c h A n g l e , 0 V a r i a t i o n & max 5 . Heading A n g l e , '? V a r i a t i o n 6 . C o n t r o l T r a v e l s F r e q u e n c y & max.

(SSSA & P i l o t ) 7 . C o n t r o l F o r c e s D i r e c t i o n & max.

8. G e a r , F l a p & T h r o t t l e P o s i t i o n P o s i t i o n Max. & mean 9. TIM 1 0 . P i l o t Comments C o n f i g u r a t i o n -- p r i o r t o m i s s e d a p p r o a c h p o i n t : g e a r down, f l a p s l a n d i n g , A/S = 1 0 0 k i a s , power a s r e q u i r e d .

-- a f t e r m i s s e d a p p r o a c h p o i n t : g e a r up, f l a p s up, A/S = b e s t r a t e of c l i m b A / s , power = max. c o n t i n u o u s .

D . P r e c i s i o n Heading Control -- T h i s t a s k d o e s n ' t tend t o exag-

g e r a t e t h e maneuvering requirements of t h e a i r c r a f t but i t should point out any s e r i o u s d e f i c i e n c i e s t h a t may e x i s t . The maneuver w i l l be accomplished by merely g i v i n g lo and 2 " heading changes t o t h e p i l o t by means of a ground c o n t r o l l e r o r by on-board commands. This maneuver could probably be coordinated w i t h t h e ILS approach t a s k .

The d a t a r e q u i r e d f o r t h i s t a s k i s a s follows: Parameter Evaluation C r i t e r i a 1. A/S Looking f o r v a r i a t i o n i n A/S, 2. A l t .

A l t , Heading Angle, Control A c t i v i t y 3 . Bank Angle, $ and Turbulence Level.

4. Heading Angle, Y 5. Control T r a v e l s (SSSA & P i l o t ) 6. TIM 7. P i l o t Comments 8. Heading Commands Configuration -- c l e a n & d i r t y , A/S = 100 k i a s - 150 k i a s , a l t . c o n s t a n t from 2,000 f t - 5,000 f t AGL, power a s r e q u i r e d .

3 . Define t h e f i e l d of p i l o t s t h a t i s a p p l i c a b l e t o t h e mission.

The f i e l d of p i l o t s t l m t could apply t o t h i s mission could become so l a r g e t h a t hundreds of hours of f l y i n g time could be expended i n g a t h e r i n g d a t a . However, t h e main concern would be t h e changes i n t h e handling q u a l i t i e s from t h e unmodified t o t h e modified model 99, and t h i s would narrow t h e f i e l d down t o a minimum number of p i l o t s . For t h i s e v a l u a t i o n t h e program p i l o t , some K.U. p i l o t s and one p r o f e s s i o n a l model 99 o p e r a t o r would probably provide enough d a t a t o g e n e r a t e a reasonable e v a l u a t i o n . However, any a d d i t i o n a l p i l o t s would tend t o add t o t h e c r e d i b i l i t y of t h e e v a l u a t i o n , Program Organization T h i s program w i l l be u s i n g t h e standard model 99 a s t h e base l i n e d a t a . Therefore, a s soon a s t h e a i r c r a f t r e t u r n s from NASA-FRC t h e unmodified model 99 w i l l be simulated by mechanically i n t e r c o n n e c t i n g t h e SSSA and p i l o t c o n t r o l s . The e v a l u a t i o n w i l l b e conducted by b u i l d i n g a f l i g h t plan u t i l i z i n g t h e t a s k o r maneuvers d e s c r i b e d above.

One such scheme could be a s f o l l o w s : 1 ) 2 t o 3 c y c l e s of t h e v e r t i c a l S maneuvers followed by a descent t o t h e ILS a l t i t u d e , 2 ) p r e c i s i o n heading v e c t o r s t o a 90' ILS i n t e r c e p t , 3) ILS flown t o a missed approach p o i n t , 4 ) go-around from l a n d i n g c o n f i g u r a t i o n , 5) p r e c i s i o n heading v e c t o r s back t o t h e ILS l o c a l i z e r a t an a l t i t u d e 500 f t above t h e l o c a l i z e r course, 6 ) modified g l i d e s l o p e i n t e r c e p t flown t o missed approach, 7 ) go-around. ( s e e Fjgure 3.)

Figure 3 . T y p i c a l F l i e h t Profile Airspeed A l t i t u d e ( F t . ) F l i g h t Task F l i g h t Configuration (Kias) o r A s Noted Number Time (Min.)

120 Clean Clean ILS i n t e r c e p t a l t i t u d e Gear dn, ILS i n t e r c e p t F l a p s a p p r . a l t i t u d e G l i d e s l o p e Gear dn , a l t i t u d e Glaps dn.

Clean, max.

ILS d e c i s i o n Best R / C h e i g h t . a i r s p e e d cont. pwr.

Clean Clean I L S i n t e r c e p t a l t . + 500 f t .

G l i d e s l o p e Gear dn, a l t i t u d e F l a p s dn.

ILS d e c i s i o n Best R / C Clean, max.

h e i g h t a i r s p e e d c o n t . p r n .

Figure 4 . Typical F l i g h t P r o f i l e C o n f i g u r a t i o n s T h i s scheme of t a s k would d e f i n e t h e o v e r a l l mission t h a t t h e p i l o t r a t i n g would d e f i n e . While each t a s k i s being accomplished and a f t e r t h e t a s k t h e p i l o t comments would need t o be recorded and analyzed.

A f t e r t h e whole mission i s accomplished then t h e "Cooper-Harper" s c a l e would be u t i l i z e d t o g e n e r a t e t h e a b s o l u t e p i l o t r a t i n g . Each of t h e designated p i l o t s would perform a s i m i l a r mission and g e n e r a t e a p i l o t r a t i n g . The q u a n t i t a t i v e d a t a , a i r s p e e d , a t t i t u d e c o n t r o l f o r c e s , e t c . , would then be c o r r e l a t e d w i t h t h e p i l o t r a t i n g and become an i n t e g r a l p a r t of t h e e v a l a u a t i o n .

A f t e r t h e SSSA system i s f u l l y developed, an analogous e v a l u a t i o n w i l l be conducted on t h a t a i r c r a f t and compared with t h e base l i n e d a t a .

T h i s d a t a w i l l d e f i n e t h e d e g r a d a t i o n s o r improvements i n t h e handling q u a l i t i e s .

F l i g h t Time Estimation The f l y i n g t i m e i s going t o be a f u n c t i o n of t h e number of evalua- t i o n p i l o t s . However, assuming t h a t f o u r p i l o t s a r e used ( p r o j e c t p i l o t , two K . U . p i l o t s and one c i v i l i a n o p e r a t o r ) a r e a s o n a b l e amount of f l y i n g would be u t i l i z e d . A t y p i c a l p r o f i l e o r mission and time e s t i m a t e i s shown i n Fig. 3 . This scheme shows a t o t a l t a s k time of approximately one hour, however, t h i s does n o t i n c l u d e t h e time f o r t a k e - o f f , l a n d i n g and maneuvering i n t o t h e t e s t a r e a . T h i s w i l l normally r e q u i r e approxi- mately 0 . 3 h r . which makes a t y p i c a l mission 1 . 3 h r s . It i s n e c e s s a r y t o f l y o n l y one e v a l u a t i o n p i l o t on each p r o f i l e so t h a t t h e second p i l o t doesn't become f a t i g u e d and i n f l u e n c e d by t h e f i r s t p i l o t .

Therefore, f o u r p i l o t s have a t o t a l time o f 5 . 3 hours. I f t h e same time i s u t i l i z e d f o r t h e e v a l u a t i o n of t h e modified a i r c r a f t then t h e time would be 1 0 . 6 hours. T h i s e s t i m a t e i s probably a c c u r a t e w i t h i n +loo%.

Such f a c t o r s a s p i l o t performance, a i r c r a f t sequencing, p i l o t d e b r i e f i n g , e t c . can very l i k e l y i n c r e a s e t h e time s u b s t a n t i a l l y .

APPENDIX C ENVIROWIENTAL TEST PLAN 1 . 0 PURPOSE To provide an environmental t e s t s p e c i f i c a t i o n f o r t h e e l e c t r o n i c components of t h e SSSA system. The equipment t o be t e s t e d w i l l i n c l u d e t h e computer c a r d s , d r i v e c a r d s , card mounting r a c k and any a s s o c i a t e d wiring and switches w i t h i n t h e r a c k .

2.0 TEST REQUIREIIENTS 2.1 ALTITUDE A l t i t u d e t e s t i n g w i l l n o t be r e q u i r e d . The a i r c r a f t t h i s equipment w i l l be used i n i s u n p r e s s u r i z e d and normally w i l l n o t be flown above 10,000 f e e t .

The c r u i s e a l t i t u d e f o r f l i g h t t e s t i n g of t h e SSSA system i s 5,000 f e e t and i s considered by engineering t o be low enough n o t t o warrant a l t i t u d e t e s t i n g .

2.2 TMPERATURE Subject t e s t u n i t t o a c o l d soak temperature of 0°F and a h o t soak of 16OoF. The t e s t u n i t w i l l be f u n c t i o n a l l y checked f o r opera- t i o n b e f o r e beginning temperature t e s t . The temperature w i l l be lowered t o t h e cold soak temperature and h e l d w i t h i n 10°F f o r t h r e e hours. A t t h e end of t h e soak p e r i o d t h e t e s t u n i t w i l l be f u n c t i o n a l l y checked and t h e n allowed t o r e t u r n t o ambient temperature.

When t h e t e s t u n i t tempcrature h a s r e t u r n e d t o ambient an a d d i t i o n a l f u n c t i o n a l t e s t w i l l be r e q u i r e d . Cycle w i l l be repeated f o r t h e hot soak w i t h t h e same t y p e of checking procedures.

2.3 VIURATION The v i b r a t i o n s h a l l be a p p l i e d i n s e p a r a t e t e s t s t o each of t h r e e mutually perpendicular a x e s of t h e t e s t u n i t .

V i b r a t i o n a p p l i e d s h a l l be s i n u s o i d a l and t h e frequency s h a l l be cycled a t a l o g a r i t h m i c r a t e between t h e frequency l i m i t s , and a t t h e a c c e l e r a t i o n l e v e l s p r e s c r i b e d by Figure 1. One complete sweep up and down between t h e p r e s c r i b e d frequency l i m i t s s h a l l be made f o r each a x i s and s h a l l span approximately 1 5 minutes (7 112 minutes up and 7 112 minutes down). Test i n t e r r u p t i o n s a r e p e r m i t t e d , but t h e c l o c k s h a l l be stopped d u r i n g any such i n t e r r u p t i o n s . During t h e frequency sweep any r e s o n a n t f r e q u e n c i e s s h a l l b e recorded. A resonance dwell t e s t s h a l l then be made a t each of t h e recorded resonance f r e - quencies, t h e dwell t i m e being a maximum of two minutes a t each f r e - quency.

The t e s t u n i t w i l l be given o p e r a t i o n a l f u n c t i o n a l checks b e f o r e and a f t e r v i b r a t i o n i n any a x i s .

3 . 0 GENERAL NOTES 3.1 Adequate r e c o r d s of a l l t e s t s performed s h a l l be maintained.

3.2 A t t h e completion of any p o r t i o n of t h i s t e s t i n g (i.e. a t t h e f u n c t i o n a l t e s t ) a "covers o f f " i n s p e c t i o n s h a l l be performed and noted b e f o r e t h e next phase of t h e t e s t i s s t a r t e d . Any d i s c r e p a n c i e s discovered s h a l l be remedied and t h e a p p r o p r i a t e p o r t i o n of t h e environ- mental t e s t ( a s determined by t h e P r o j e c t Manager) w i l l be r e p e a t e d .

FREQUENCY - CPS I I . T E S T S C I ~ I E D U L E 7 4 4.0 REFERENCES 1. Anon., "Flight Assurance Testing (Environmental) Electronic and Electromechanical Equipment," Process Specification No. 21-2, NASA Flight Research Center, March 5, 1969.

CRlNC LABORATORIES Chemical Engineering Low Temperature Laboratory Remote Sensing Laboratory Flight Research Laboratory Chemical Engineering Heat Transfer Laboratory Nuclear Engineering Laboratory Environmental Health Engineering Laboratory Information Processing Laboratory Water Resources Institute Technology Transfer Laboratory