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A i r c r a f t C o n t r o l U s i n g E n g i n e T h r u s t
A H i s t o r y o f L e a r n i n g T O C R e a l - T i m e
Jennifer H. Cole NASA Dryden Flight Research Center
L e a r n i n g f r o m H i s t o r y …
• Loss-of-control events • Causes include – F l i g h t c o n t r o l s y s t e m f a i l u r e s – M e c h a n i c a l c a b l e b i n d i n g , h y d r a u l i c l e a k – I n - f l i g h t s t r u c t u r a l f a i l u r e s – H o s t i l e i n t e n t • Significant loss-of-control events – C o m m e r c i a l : 7 4 7 , 7 3 7 , D C - 1 0 , L - 1 0 1 1 , A - 3 0 0 – M i l i t a r y : A - 1 0 , B - 5 2 , F / A - 1 8 , C - 5 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
A i r c r a f t C o n t r o l U s i n g E n g i n e T h r u s t
• TOC - Throttles Only Control • TOC is – P i l o t i n g t e c h n i q u e – N o s o f t w a r e o r h a r d w a r e – H i s t o r i c a l l y s u c c e s s f u l i n s a v i n g l i v e s
TOC history i n loss-of-control events …
J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
P a s t T O C A c c i d e n t s / In c i d e n t s
created from FWB 01-16g Aileron/ Flaps Rudder Elevator Stabilizer Engines Cause Accidents Spoiler UAL DC-10 no no no no no center out fan disk/hyd JAL B747 no yes no no no all OK aft bulk/hyd USAF C-5A yes yes no no no all OK cargo ramp/hyd USAF B-52H yes yes no no yes all OK hyd leak/tail Turkish DC-10 yes ? no no no all OK door/cables/hyd USN F/A-18 no no no no no all OK hyd act leak Incidents USAF A-10 yes yes no no no all Ok AAA/cables USAF B-52G yes yes no no yes all OK hyd leak/tail Delta L-1011 yes yes yes yes one side all OK jammed stab hardover DHL A300 no no no no no all OK SAM/hyd J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
1 9 7 2 : D C - 1 0 A m e r i c a n A i r l i n e s
• Flight 96 was climbing through 11,750 feet at 260 KIAS • Flight crew felt a ‘ t hud ’ and degraded controls • The crew managed to regain control of the plane and safely land – S l u g g i s h e l e v a t o r r e s p o n s e , n o r u d d e r c o n t r o l w a s a v a i l a b l e – T O C u s i n g r e v e r s e t h r u s t k e p t t h e a i r c r a f t o n t h e r u n w a y • Separation of cargo door = rapid decompression = failure of the cabin floor over the bulk cargo compartment.
– R u d d e r a n d 5 0 % o f t h e e l e v a t o r , s t a b i l i z e r c o n t r o l w e r e l o s t – M i n o r f u s e l a g e d a m a g e – S u b s t a n t i a l d a m a g e t o t h e l e a d i n g e d g e a n d u p p e r s u r f a c e o f t h e l e f t h o r i z o n t a l s t a b i l i z e r .
J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
M a y 1 9 7 4 : U S A F B - 5 2 H
• W r i g h t P a t t e r s o n A i r F o r c e B a s e , O H • D e v e l o p e d h y d r a u l i c l e a k - n o t a i l c o n t r o l s – S t a b t r i m f o r s p e e d c o n t r o l , s p o i l e r s f o r r o l l c o n t r o l • C r e w q u i c k l y l e a r n e d h o w t o u s e t h r o t t l e s a n d a i r b r a k e s t o c o n t r o l p i t c h • C r e w f l e w f o r 3 0 m i n u t e s , d e c i d e d t o a t t e m p t l a n d i n g – L o w e r e d g e a r , p h u g o i d c a u s e d a i r c r a f t t o l o s e 8 0 0 0 f e e t • C r e w a g a i n a t t e m p t e d a l a n d i n g , b u t h i t h a r d – A l l 8 c r e w m e m b e r s w a l k e d a w a y – A i r c r a f t w a s d e s t r o y e d b y f i r e • A s a d i r e c t r e s u l t , T O C p r o c e d u r e s w e r e d e v e l o p e d f o r t h i s e x a c t s c e n a r i o a n d a r e p r a c t i c e d b y B - 5 2 c r e w s t o t h i s d a y J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
A p r i l 1 9 7 5 : U S A F C - 5 A
• I n i t i a l m i s s i o n o f O p e r a t i o n B a b y l i f t • D e p a r t e d S a i g o n , S o u t h V i e t n a m • 3 2 8 t o t a l o n b o a r d , i n c l u d i n g 2 4 3 o r p h a n s • 2 3 0 0 0 f e e t : S t r u c t u r a l f a i l u r e a t r e a r r a m p – S u d d e n d e c o m p r e s s i o n = s e v e r e d r u d d e r , e l e v a t o r c a b l e s a n d l o s s o f 2 h y d r a u l i c s y s t e m s – C r e w h a d n o t a i l c o n t r o l • F u n c t i o n a l c o n t r o l s – O n e a i l e r o n , s p o i l e r s – E n g i n e s f o r p i t c h c o n t r o l J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
A p r i l 1 9 7 5 : U S A F C - 5 A
• Pilots wrestled with the controls using TOC • Crew made a practice landing at 10000 ft – E n g i n e s f o r p i t c h c o n t r o l – W i n g s p o i l e r s a n d 1 r e m a i n i n g a i l e r o n f o r r o l l c o n t r o l • Crew descended to 4000 feet to prepare for landing – A g a i n , g e a r d r o p i n i t i a t e d a p h u g o i d • Rate of descent increased rapidly during approach • Aircraft slammed d own in a rice paddy 3 miles short of runway • Overall, 175 of the 328 aboard survived • Worst single non-combat U.S. military aviation disaster J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
1 9 8 1 : U S A F B - 5 2 G
• Warner Robins AFB, Georgia • Developed hydraulic leak – S u b s e q u e n t l y l o s t a l l t a i l c o n t r o l s • Crew followed established hydraulics-off procedure – U s e d e n g i n e s a n d s p o i l e r s f o r c o n t r o l • The aircraft hit hard and broke fuselage, but was later repaired • All onboard survived with no injuries J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6
A u g u s t 1 9 8 5 : J A L 1 2 3 B - 7 4 7
• Tokyo with 509 onboard • 24000 ft: aft bulkhead failed – S e v e r e d 4 s e t s o f h y d r a u l i c c o n t r o l l i n e s ( n o c o n v e n t i o n a l c o n t r o l ) • Crew flew for 30 minutes using TOC • Eventually c rashed into a mountain • 505 passengers perished, 4 survived J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 0
J A L 1 2 3 S u r v i v o r S t o r y
Survivors included a flight attendant: • “ T here was a sudden loud noise, somewhere to the rear and overhead. It hurt my ears and the cabin filled with white mist … There was no sound of any explosion, but ceiling panels fell off, and oxygen masks fell down. ” Then she felt the aircraft going into a falling leaf mode.
Some victims survived impact, but succumbed to e xposure during the night J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 1
J A L 1 2 3 In v e s t i g a t i o n F i n d i n g s
• Further investigation revealed: – T a i l s t r i k e 7 y e a r s e a r l i e r h a d d a m a g e d r e a r p r e s s u r e b u l k h e a d , w h i c h w a s t h e n i m p r o p e r l y r e p a i r e d • Accident prompted Boeing to re-inspect aft bulkhead repairs.
• Ironically, UAL pilot Denny Fitch heard of the JAL 123 incident and spent some time l earning TOC on his aircraft, the DC-10. It would later come in handy … J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 2
J u l y 1 9 8 9 : U A L 2 3 2 D C - 1 0
• 37000 feet and 296 onboard: uncontained No.2 ( tail) engine failure – S h r a p n e l f r o m f a n b l a d e s e v e r e d li n e s t o a l l 3 h y d r a u l i c s y s t e m s • Crew d iscovers all conventional control is gone – O n l y t h e t w o w i n g e n g i n e s a r e o p e r a t i o n a l - T O C i s o n l y o p t i o n • Crew decided to attempt landing i n Sioux City, Iowa J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 3
U A L 2 3 2 D C - 1 0
S i o u x C i t y , Io w a
Note - right-hand turns
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U A L 2 3 2 D C - 1 0
• Crew learned TOC real-time with the help of Denny Fitch • Remarkable teamwork and crew resource management, exceptional experience level, uncanny timing and placement, and extraordinary luck contributed to a survivable crash-landing • Al Haynes, Captain of UAL 232, still travels the country to tell the story • Miraculously, 185 survived J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 5
U A L 2 3 2 D C - 1 0
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E a s t w i n d 5 1 7 B - 7 3 7
• 4000 feet and 53 onboard: U ncommanded r oll to the right – P i l o t i n i t i a l l y f e l t a r u d d e r ‘ b u m p ’ t o t h e r i g h t , t h e n t h e a i r c r a f t s u d d e n l y r o l l e d t o t h e r i g h t • Pilot applied opposite rudder, but it felt stiff – T h e n h e u s e d o p p o s i t e a i l e r o n a n d a s y m m e t r i c p o w e r t o m a i n t a i n c o n t r o l • Emergency d eclared and checklist p erformed – P a r t o f c h e c k l i s t i n c l u d e d t u r n i n g o f f y a w d a m p e r – A i r c r a f t b e c a m e c o n t r o l l a b l e a g a i n • Safe landing performed • Further investigation uncovered previous problems with u ncommanded rudder deflections – R u d d e r ‘ b u m p s ’ d u r i n g d e p a r t u r e a n d d i f f i c u l t y t r i m m i n g a i r c r a f t • FDR was removed for data analysis J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 7
N o v e m b e r 2 0 0 3 : D H L A - 3 0 0
• Departing Baghdad, Iraq with cargo, 3 crew onboard • At 8000 feet a surface-to-air missile (SAM) hit the aircraft • Missile did serious damage to left wing – L o s t a l l h y d r a u l i c c o n t r o l – N o . 2 e n g i n e o n f i r e • Crew u s ed T OC to control the aircraft for 16 minutes before landing • All 3 crewmembers walked away J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 8 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 1 9
H i s t o r i c a l l y , T O C h a s s a v e d l i v e s
• Military showed initiative • Commercial world has yet to initiate TOC procedures – J A L 1 2 3 a n d U A L 2 3 2 a c c i d e n t s • M o r e d e t a i l e d i n s p e c t i o n s • I m p r o v e d r e p a i r p r o c e d u r e s • M o r e r e d u n d a n c y b u i l t i n t o a i r c r a f t – B u t n o i n i t i a t i v e t o r e c o g n i z e T O C a s p a r t o f a n e m e r g e n c y p r o c e d u r e • Relative success of UAL 232 crew to control their aircraft with throttles inspired a NASA Dryden engineer to explore propulsive thrust as a means for automated control J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 0
A u t o m a t e d T h r o t t l e s - O n l y C o n t r o l
• 1990s - Digitally controlled engines • Possible to create s o ftware to talk to the engines and control the aircraft using only propulsive thrust • Propulsion-controlled aircraft (PCA) project was born EC94 42805-1 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 1
P C A P r o j e c t
• PCA became a full-fledged Ames-Dryden initiative – F - 1 5 a n d t h e M D - 1 1 • TOC was extensively demonstrated – P i l o t e d s i m u l a t i o n s i n c l u d e d • T r a n s p o r t ( B - 7 2 0 , B - 7 2 7 , B - 7 5 7 , M D - 9 0 , M D - 1 1 , B - 7 4 7 , C - 1 7 ) • F i g h t e r s ( F - 1 5 , F / A - 1 8 ) a n d t h e S R - 7 1 – P i l o t e d f l i g h t s i n c l u d e d • T r a n s p o r t ( M D - 1 1 , B - 7 4 7 , C - 1 7 ) • F i g h t e r s ( F - 1 5 , F / A - 1 8 ) • T r a i n e r s ( T - 3 8 , T - 3 9 ) EC97-43933-4 • L e a r 2 4 b i z j e t a n d P A - 3 0 S82-28715 EC97-44272-6 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 2 ECN 2845 ECN-4242
P r o p u l s i o n - C o n t r o l l e d A i r c r a f t
J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 3 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 4
P C A P r o j e c t
• PCA was demonstrated with the landing of an MD-11 u sing only engine thrust for control!
– G o r d o n F u l l e r t o n o n A u g u s t 2 9 , 1 9 9 5 • Program c ontinued to demonstrate ILS-coupled landings, e nvelope expansion to 30000 ’ , 360 KIAS and even t urning off hydraulics EC95 43247-3 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 5 EC95 43355-1 EC95 43247-1 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 6 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 7 , d e l p u o C e - h S t L g I t n i o s N u t o l n i i p s b w e o n N k e t c o n l i e l p u o b t r u u a t e t a r e d o M J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 8 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 2 9 N A S A F W B 0 1 - 1 9 a T h r o t t l e s - O n l y P i t c h a n d R o l l C o n t r o l P o w e r M a x i m u m c a p a b i l i t y ( w i t h o u t a f t e r b u r n i n g ) 2 0 0 k t s , l o w a l t i t u d e 1 . 5 A - 3 0 0 B e s t a r e a l l B - 7 6 7 B - 7 5 7 t w i n j e t s !
D C - 1 0 A - 3 2 0 M D - 1 1 B - 7 7 7 B - 7 4 7 A - 3 3 0 B - 7 3 7 - 3 0 0 L - 1 0 1 1 A - 3 4 0 0 . 5 B - 7 2 0 B - 7 3 7 - 2 0 0 C - 1 7 B - 7 2 7 P i t c h C - 1 4 1 T - 3 8 F - 1 5 p a r a m e t e r , M D - 9 0 F / A - 1 8 ( M a x t h r u s t - t r i m t h r u s t ) x m o m e n t a r m B A C 1 - 1 1 L e n g t h x w e i g h t - 0 . 5 T a i l - m o u n t e d e n g i n e s d o n ’ t d o w e l l w i t h T O C - 1 L e a r G u l f s t r e a m I V - 1 . 5 0 2 4 6 8 1 0 R o l l p a r a m e t e r , D i f f e r e n t i a l t h r u s t x m o m e n t a r m x s w e e p f a c t o r J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 l e n g t h x s p a n x w e i g h t 3 0 S i m u l a t i o n F l i g h t MD-11 F-15 B-747 T h i s c h a r t d e p i c t s t h e B-720 r e l a t i v e a m o u n t o f T O C r e s e a r c h t h a t B-757 h a s b e e n p e r f o r m e d o n j e t - p o w e r e d F-18 c o n f i g u r a t i o n s … Learjet C-17 T-38 B-727 B o r r o w e d f r o m F W B 2 / 0 6
P C A i n C o m m e r c i a l F l e e t … ?
In 1996, PCA was beneficial for many reasons • Enabled an aircraft with damaged flight controls to safely land • No additional weight (just software was loaded on the aircraft) • Repeatable, survivable results over a wide variety of conditions • Demonstrated to 21 airline, D oD , FAA, Boeing and Airbus pilots • Useful in a variety of situations – S t r u c t u r a l o r c o n t r o l s y s t e m f a i l u r e , l o s s o f h y d r a u l i c f l u i d , d a m a g e , e t c .
So why didn ’ t PCA ever make it on a ny aircraft ?
• Potential cost of certification • Industry climate at the time disliked any r etrofit systems • Potential liability issues with airframe manufacturers J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 3 2
F a l l 2 0 0 5 : P C A R P r o j e c t
In the post-9/11 world, DHS has sponsored an effort to bring both PCA and TOC to the commercial fleet • PCAR = Propulsion-Controlled Aircraft Recovery • PCA – T r a n s f e r p r e v i o u s P C A e x p e r i e n c e t o 7 4 7 - 4 0 0 – W o r k i n g w i t h i n d u s t r y e x p e r t s t o i n t e g r a t e P C A i n t o c u r r e n t f l e e t – E f f o r t i s o n - g o i n g • TOC – A i r c r a f t c o n t r o l l a b i l i t y a n d r e c o v e r y – I n i t i a l l o o k a t B - 7 5 7 J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 3 3
P C A R B a c k g r o u n d - T O C
• Joint DHS/UAL/NASA effort • Provide pilots with another tool in their ‘ t oolbag ’ – W i n d s h e a r , e v a s i v e m a n e u v e r s , s i m i l a r t o e x i s t i n g e m e r g e n c y p r o c e d u r e s • Developing Throttles-Only Control t echniques for commercial fleet – C u r r e n t f o c u s o n t h e 7 5 7 - 2 0 0 • Research group comprised of pilots and engineers from NASA and UAL • Deliverable: Generate TOC product for the 757-200 aircraft – T e s t a n d l i n e p i l o t e v a l u a t e d , i n b o t h s i m u l a t i o n a n d f l i g h t J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 3 4
P C A R B a c k g r o u n d - T O C
• Evaluate effectiveness of T OC on the 757 – 6 4 h o u r s i n s i m , 4 h o u r s i n f l i g h t s o f a r • Results so far indicate that TOC on 757-200 is very favorable • Initial Findings For 757 – A i r c r a f t i s v e r y r e s p o n s i v e t o t h r u s t c o n t r o l • A d d t h r u s t = s l o w d o w n , b u t c l i m b • R e d u c e t h r u s t = s p e e d u p , b u t d e s c e n d – D u r i n g t h e l a n d i n g f l a r e - a d d t h r u s t • New pilots conducted survivable landings on their first try – L a n d i n g s a r e o f t e n 2 0 0 + K I A S – J u s t l i k e i n r e a l - l i f e T O C e v e n t s - p r a c t i c e , p r a c t i c e , p r a c t i c e • VSI is valuable tool for establishing t rim speed and general TOC maneuvering J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 3 5
P C A R B a c k g r o u n d - T O C
• Finish Phase I by end of FY06 – 3 0 h o u r s o f s i m u l a t i o n s , 5 m o r e h o u r s o f f l i g h t – T O C c h e c k l i s t e v a l u a t e d b y U A L 7 5 7 t e s t a n d l i n e p i l o t s • Enter Phase II – E x t e n d T O C i n v e s t i g a t i o n o n 7 7 7 , 7 6 7 , A 3 2 0 p l a t f o r m s – D e t e r m i n e c a n d i d a t e p l a t f o r m f o r f u r t h e r T O C d e v e l o p m e n t – S p e n d 5 0 h o u r s s i m u l a t i o n , 2 f l i g h t s t o g e n e r a t e T O C c h e c k l i s t J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 3 6
P C A R S u m m a r y
• Working to get p roven technology into the commercial fleet • Controlling an aircraft using propulsive thrust is beneficial – I s i n d e p e n d e n t o f f a i l u r e ( s t r u c t u r a l , c o n t r o l s y s t e m , d a m a g e , e t c ) • TOC applies to older, less digital aircraft • PCA would be a relatively easy a dd-on for newer aircraft • Pilots and aviation advocacy groups support the technology • J A L 1 2 3 , U A L 2 3 2 a n d C - 5 A c r a s h e s a l o n e c l a i m e d o v e r 1 1 0 0 l i v e s – H o w m a n y m o r e c o u l d h a v e b e e n s a v e d w i t h P C A / T O C t e c h n o l o g y ?
J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 3 7
Any Questions?
J u l y 2 6 2 0 0 6 A i r V e n t u r e , O s h k o s h 2 0 0 6 3 8