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17. SUMMARY OF THE GENERAL AVIATION MANUFACTURERS' POSITION ON AIRCRAFT PISTON ENGINE EMISSIONS J, Lynn H e l m s P i p e r A i r c r a f t Corporation Lock Haven, Pennsylvania The members of t h e General Aviation Manufacturers Association are pleased t o p a r t i c i p a t e i n t h i s symposium and wish t o express t h e i r appreciation t o NASA, p a r t i c u l a r l y t h e L e w i s Research Center, f o r host- i n g t h e meeting. A t e c h n i c a l meeting, with r e p r e s e n t a t i o n from a l l groups a s s o c i a t e d with a i r c r a f t p i s t o n engine emissions, i s p a r t i c u l a r l y a p p r o p r i a t e a t t h i s t i m e . A considerable amount o f t e c h n i c a l r e s u l t s from t h e laboratory, test s t a n d s , and f l i g h t tests i s now a v a i l a b l e , This meeting f i l l s a need f o r an update t o a l l concerned on what is known and not known about a i r c r a f t p i s t o n engine emissions and t h e re- s u l t a n t i n s t a l l a t i o n and o p e r a t i o n a l unknowns.
The standards governing t h e emissions of a i r c r a f t p i s t o n engines w e r e e s t a b l i s h e d n e a r l y 3 years ago. Those standards w e r e e s t a b l i s h e d without a v a l i d t e c h n i c a l b a s i s a p p l i c a b l e t o a i r c r a f t engines.
I n t h e public hearings h e l d a t t h a t t i m e , t h e General Aviation Manufacturers Association pointed o u t t h e extremely small c o n t r i b u t i o n t o atmospheric p o l l u t i o n made by p i s t o n engine a i r c r a f t .
It w a s pointed out t h a t t h e gains i n environmental q u a l i t y would be extremely small (completely un- measurable) and t h e c o s t s extremely high i n proportion t o any b e n e f i t s .
On t h e b a s i s of Ehe tests completed s i n c e then, and t h e considerably g r e a t e r (but still incomplete) knowledge t h a t w e have today, t h e conclu- s i o n s w e expressed i n t h e 1973 p u b l i c hearings have been reinforced.
W e s t r o n g l y recommend t h a t t h e EPA r e s c i n d t h e a i r c r a f t p i s t o n engine emissions r e g u l a t i o n s c u r r e n t l y on t h e books. This should be done because of t h e very small emission reduction p o t e n t i a l and t h e very poor benefit-cost r a t i o involved in t h i s form o f emission reduction. The l i m i t e d resources of t h i s i n d u s t r y can f a r b e t t e r be devoted t o items of much g r e a t e r b e n e f i t t o the c i t i z e n s of t h i s country - reducing n o i s e , w i l l i n c i d e n t l y reduce exhaust emis- improving f u e l e f f i c i e n c y (which s i o n s ) , and improving t h e s a f e t y , o p e r a t i o n a l , and economic a s p e c t s o f our a i r c r a f t , a l l f a r g r e a t e r c o n t r i b u t i o n s t o our t o t a l n a t i o n a l t r a n s - p o r t a t i o n system.
I have summarized the p o s i t i o n of t h e General Aviation Manufacturers Association. W e b e l i e v e i t is based on t h e f a c t s , and it is t h e same However, w e recognize t h a t , r e g a r d l e s s of our p o s i t i o n w e held i n 1973.
p o s i t i o n and r e g a r d l e s s of t h e f a c t s as w e see them, t h e r e g u l a t i o n s re- garding a i r c r a f t p i s t o n engine emissions are on t h e books. W e have been working hard t o respond t o t h e s e r e g u l a t i o n s t o determine i f it is pos- s i b l e t o meet t h e r e g u l a t i o n s o r t o determine what level can b e ap- proached and t o d e f i n e an o r d e r l y program f o r compliance.
Up t o now t h e research e f f o r t on reducing a i r c r a f t p i s t o n engine emissions has p r i m a r i l y been concentrated on o p e r a t i n g with l e a n e r fuel- air mixtures t o reduce hydrocarbons and carbon monoxide. Other ap- proaches, such as modifications t o spark timing, which could possibly be implemented w i t h i n t h e next several y e a r s , have not shown promise.
f l i g h t , t h e c u r r e n t mixture leaning p r a c t i c e s For t h e en r o u t e phase of provide near-optimum f u e l - a i r r a t i o s from both standpoints of fIlel economy and exhaust emissions. Development e f f o r t s on reducing engine emissions have properly been concentrated on operations i n the v i c i n i t y t h e a i r p o r t where most r i c h e r than optimum mixture operations occur.
of The research results show t h a t although some fuel-injected engines might operate s a t i s f a c t o r i l y with l e a n e r than c u r r e n t f u e l scheduling i n t h e i n i t i a l climb and approach modes they s t i l l would not m e e t EPA standards.
Also, t h e r e appears t o be a p o s s i b i l i t y t h a t with t h e a d d i t i o n of complex and c o s t l y automatic mixture c o n t r o l devices some f u r t h e r reduction i n emission levels might be obtained. Fully e f f e c t i v e devices are many years away. It is n o t p o s s i b l e t o p r e d i c t , with confidence, how c l o s e these changes could b r i n g t h e body of a i r c r a f t p i s t o n engines toward meeting the e x i s t i n g standards. There is considerable v a r i a t i o n from a given class, and t h e e f f e c t s of produe- one engine model t o another of t i o n t o l e r a n c e s , test conditions, engine hour accumulation, and a i r c r a f t : i n s t a l l a t i o n c o n s t i t u t e a d d i t i o n a l unknowns.
L e t me emphasize t h a t &he p r a c t i c a l i t y of t h e emission reduction approaches which have been t e n t a t i v e l y i d e n t i f i e d have y e t t o be proven.
In the case of some of t h e automatic mixture c o n t r o l devices, t h e imple- Illenting hardware technology has y e t t o be developed and t e s t e d . Current a i r c r a f t f u e l c o n t r o l systems have evolved over many years of development and refinement based on f i e l d experience. Certainly much can be done on the test stand and on i n - f l i g h t tests. However, before w e d e l i v e r an a i r c r a f t with a new f u e l scheduling system t o a customer it must be t e s t e d over t h e f u l l spectrum of conditions expected i n operation includ- i n g t i m e . W e must have a f i r m handle on a l l of t h e o p e r a t i o n a l , environ- mental, and manufacturing v a r i a b l e s involved and t h e i r e f f e c t s on s a f e t y and operation of t h e a i r c r a f t . I n the case of modified f u e l scheduling, t h i s r e q u i r e s a c o s t l y and t i m e consuming process using c u r r e n t types o f i n j e c t o r systems. In t h e case of automatic mixture c o n t r o l devices, it would r e q u i r e a much longer and more c o s t l y development program and t h i s would r e s u l t i n a major i n c r e a s e i n production c o s t s f o r very l i t t l e b e n e f i t .
Based on c u r r e n t information, a p r o j e c t i o n has been made of t h e emission reductions p o s s i b l e , and rough estimates of t h e c o s t s involved have been e s t a b l i s h e d . Currently, a i r c r a f t p i s t o n engines make up approximately 0.1 percent of the t o t a l atmospheric hydrocarbon, carbon monoxide, and NOx pollution. Based on an estimated p o t e n t i a l of a 30 percent reduction in emissions during t h e landing-takeoff cycle, where 5 t o 10 percent of a v i a t i o n f u e l is burned, a reduction o f approxi- mately 2 percent i n t o t a l emissions is p r o j e c t e d f o r a t y p i c a l p i s t o n engine a i r c r a f t with a modified f u e l system. B y t h e y e a r 2000 roughly one-half of t h e f l e e t would b e made up of a i r c r a f t powered by modified On t h i s b a s i s , a reduction i n t o t a l atmospheric p o l l u t i o n o f engines.
the order of 0.001 p e r c e n t is p r o j e c t e d f o r t h e y e a r 2000. These numbers f i v e , o r even g r e a t e r i n e i t h e r could e a s i l y b e o f f by a f a c t o r of two, d i r e c t i o n . However, t h e p o i n t remains - t h e c o n t r i b u t i o n of any p o s s i b l e a i r c r a f t p i s t o n engine emission reduct'ion t o t h e t o t a l atmospheric pollu- t i o n reduction is dramatically miniscule and unmeasurable.
I f w e look a t t h e economics, i t is estimated t h a t a 5 t o 15 percent i n c r e a s e in product c o s t t o the consumer would probably be necessary f o r t h e engine and a i r c r a f t modifications required t o provide t h e emissions reductions assumed previously. With a $1 b i l l i o n average annual sales rate f o r p i s t o n engine a i r c r a f t , t h e c o s t is estimated t o be $50 t o $150 m i l l i o n p e r year, o r a t least $1 t o $2 b i l l i o n i n t h i s t i m e period. Thus, the b e n e f i t t o c o s t r a t i o works out t o be approximately 0.000001 percent p e r m i l l i o n d o l l a r s spent. Surely o t h e r f a r more important needs e x i s t f o r t h e s e resources.
It is c l e a r on the b a s i s of what w e know today (disregarding t h e cost-benefit aspect) t h a t it w i l l be impossible t o meet t h e e x i s t i n g standards by December 31, 1979, e i t h e r as t o l e v e l s o r t i m e . I f it is not p o s s i b l e t o r e s c i n d o r i n d e f i n i t e l y postpone t h e a p p l i c a b i l i t y of t h e standards, then i t i s clear t h a t both t h e i n d u s t r y and t h e government agencies represented at t h i s meeting need t o aggressively continue re- search and development e f f o r t s t o provide t h e information upon which realistic standards, and a practical schedule f o r t h e i r implementation, can be based. As a p a r t of t h i s e f f o r t , w e f e e l t h a t it i s important t h a t good, d e f i n i t i v e information regarding implementation c o s t s and schedules be developed s o t h a t a p r a c t i c a l program r e f l e c t i n g cost- b e n e f i t t r a d e s can be devised.
As t h e i n d u s t r y began preparing f o r t h i s symposium several months ago, it w a s hoped t h a t s u f f i c i e n t information would be a v a i l a b l e t o enable us t o make a concrete proposal t o modify t h e standards and t h e implementation schedule. Unfortunately, as w e have seen during t h e p a s t two days of discussion, s u f f i c i e n t knowledge is not a v a i l a b l e t o allow the d e f i n i t i o n of realistic standards. W e plan t o continue our e f f o r t s toward t h e goal of e s t a b l i s h i n g r e a l i s t i c standards and a workable imple- mentation program. Even i f the standards are rescinded, our i n d u s t r y w i l l continue with a meaningful program. It is necessary t h a t t h i s e f f o r t be continued and t h a t new standards and schedules be e s t a b l i s h e d i n t h e near f u t u r e i n o r d e r t o avoid s e r i o u s d i s l o c a t i o n w i t h i n t h e i n d u s t r y because of t h e long l e a d t i m e commitments necessary on many purchased items, such as engines, and t h e long flow t i m e i n t h e a i r c r a f t manufacturing process.
W e f e e l t h a t t h e symposium has been extremely worthwhile i n provid- i n g a f r e e exchange of information on what is known and n o t known on air- c r a f t p i s t o n engine emissions. The hidden s p e c t r e throughout is t h e p o t e n t i a l impact on f l i g h t s a f e t y : It seems very l i k e l y w e w i l l reverse 60 years i f w e continue on t h i s p r e s e n t path; that t h e p o s i t i v e t r e n d of is, w e w i l l have less f l i g h t s a f e t y .
Based on a l l t h e information a v a i l a b l e t o us today w e can draw t h e following conclusions : (1) S u f f i c i e n t t e s t i n g has now been accomplished t o confirm t r e n d s of expected r e s u l t s .
( 2 ) The technology does not e x i s t t o m e e t t h e present EPA standards o r schedule.
(3) W e do not y e t know what l i m i t s can be m e t .
( 4 ) System technology t o achieve automatic mixture c o n t r o l is p r e s e n t l y unknown.
(5) The impact of emission reduction e f f o r t s on t i m e between over- h a u l and engine r e l i a b i l i t y are completely unknown.
(6) F l i g h t s a f e t y requirements prevent t h e adoption of any system r e q u i r i n g manual l e a n i n g during t h e t a x i phase.
(7) Wide and unpredictable excursions e x i s t i n production t o l e r - ances.
(8) Each a i r c r a f t i n s t a l l a t i o n is d i f f e r e n t and not completely pre- d i c t a b l e .
(9) N o t e c h n i c a l option e x i s t s t h a t i s compatible with production and t o o l i n g l e a d times.
(10) Achieving t h e EPA emissions standards would only reduce atmos- p h e r i c p o l l u t i o n by approximately 0.001 percent.
t o hundreds of m i l l i o n s of d o l l a r s per year w i l l (11) Costs of t e n s r e s u l t f o r t h e extremely small reductions obtained.
(12) There w i l l be an adverse impact on f l i g h t s a f e t y , though w e do not know how t o quantify.
Differences with t h e s e conclusions can exist only i n degree, not s u b j e c t matter.
W e l i v e i n complex t i m e s with i d e a s and opinions s u b j e c t t o extreme criticism o r a p p r a i s a l by e i t h e r genuine e v a l u a t o r s o r purposeless d i s s i - dents. These c u l t u r a l environmental c h a r a c t e r i s t i c s are exacerbated by t h e p o l i t i c a l events of t h e day and s i n g l e - i n t e r e s t groups, e i t h e r pro o r con t o an idea.
None of t h e s e , however, r e l i e v e our j o i n t r e s p o n s i b i l i t y f o r f u l - f i l l i n g t h e e s t a b l i s h e d requirements of our r e s p e c t i v e o f f i c e s . J u s t as industry has a f i r m r e s p o n s i b i l i t y t o t a k e a l e a d i n g r o l e i n a n a t i o n a l environment improvement e f f o r t so a l s o does t h e f e d e r a l government and its included agencies and bureaus have an equal r e s p o n s i b i l i t y t o s t a n d up and b e counted when i t is t i m e t o acknowledge t h e need f o r change, Government need n o t do so with any f e e l i n g of v a l i d condemnation from i n d u s t r y o r outspoken critics. Equally, our congressional committee sys- t e m c l e a r l y e s t a b l i s h e s a recognition by t h e Congress f o r t h e need t o continually review and revise l a w s and t h e i r a p p l i c a b i l i t y .
It i s now c l e a r l y evident t h a t when these standards were e s t a b l i s h e d i n 1973 t h e n a t i o n a l mood of cleaning up t h e environment overwhelmed our knowledge of what could b e done and t h e s a f e t y aspects a f f e c t e d by estab- l i s h i n g a i r c r a f t p i s t o n engine emission standards. W e now have a j o i n t r e s p o n s i b i l i t y t o r e d i r e c t t h e two most vital resources w e have - t a l e n t
and t i m e - toward s o l v i n g problems with a much higher p o t e n t i a l pay o u t
t o our n a t i o n ' s c i t i z e n r y . Cost is merely our way of accounting f o r use of t h e s e two more v i t a l resources.
It is t i m e w e c l e a r l y state t h a t t h e p o t e n t i a l b e n e f i t of even massive e f f o r t s t o reduce a i r c r a f t p i s t o n engine emissions i s unmeasur- able at b e s t and an extremely poor use of our n a t i o n a l resources. Aside from t h e economic i m p a c t of l a r g e scale unemployment and p l a n t reduc- t i o n s , it is a case whereby s i m p l e l o g i c confirms t h a t what w e g e t i s n o t worth t h e e f f o r t . It w a s not t h e i n t e n t of Congress when it enacted t h e Clean Air Amendment of 1970 t o a r b i t r a r i l y e s t a b l i s h a b a s i s t o waste t e n s of m i l l i o n s of d o l l a r s f o r a b e n e f i t s o s m a l l t h a t even t h i s n a t i o n ' s advanced technology cannot measure. Congress f u l l y expects t h e respon- s i b l e government organization t o b r i n g such s i t u a t i o n s t o t h e i r a t t e n t i o n .
W e thereby recommend t h a t -
(1) The emissions requirements s p e c i f i e d f o r a i r c r a f t p i s t o n engines be rescinded, and (2) A j o i n t industry-government t a s k f o r c e compile a r e p o r t contain- a l l of t h e d a t a obtained (which s u b s t a n t i a t e s t h e recommen- i n g dation f o r r e c i s i o n ) w i t h t h a t r e p o r t made a v a i l a b l e t o a l l i n t e r e s t e d p a r t i e s , whether d i s s i d e n t s o r s u p p o r t e r s , r a t h e r than engage i n continuing r h e t o r i c a l debate, o r (3) I f t h e previous two recommendations cannot be accepted, then the emissions levels and schedule f o r a i r c r a f t p i s t o n engines must be i n d e f i n i t e l y postponed u n t i l such t e s t i n g has been completed as t o allow t h e establishment of meaningful values and dates.
DISCUSSION COMMENT - J. Barriage: Speaking f o r t h e FAA, Z a p p r e c i a t e t h e p r o v i s i o n s and t h e excellence of t h e discussions and p r e s e n t a t i o n s which w e have ex- perienced t h e s e p a s t 2 days. Each of u s recognizes that t h e r e is a g r e a t d e a l more t o be done. T t h i n k each of u s a l s o recognizes t h a t we need t o continue d e f i n i n g t h e work t h a t needs t o be done and t o d e f i n e t h e manner i n which w e are a b l e t o arrive a t a s o l u t i o n .
Obviously, as has been brought o u t , t h e r e are d i f f e r e n c e s of views, but P t t s healthy t o bring them o u t and d i s c u s s them. W e a p p r e c i a t e NASA-Lewis having t h i s symposium and handling i t so b e a u t i f u l l y .
COMMENT - G. Kittredge: W e , too, a p p r e c i a t e t h e opportunity t o have
been able t o t a k e part i n t h i s symposium- I n my own case, it's t h e first chance I've had to get t o g e t h e r with such a complete spectrum of t a l e n t from t h e aerospace i n d u s t r y and a s s o c i a t e d government agen- c i e s . W e look forward t o t h e p u b l i c a t i o n of t h e proceedings. We'll study t h e s e very c a r e f u l l y and w i t h thoroughness. W e want t o respond t o your comments, M r . H e l m s . To do them j u s t i c e , w e would l i k e t b study them more thoroughly on a n agency b a s i s before we comment. I have a few impromptu comments which are my own only. I do want t o restate, with regard t o our a i r q u a l i t y arguments, t h a t c e r t a i n l y what you say i s cor- r e c t i n so f a r as nationwide impact is concerned. With r e s p e c t t o gen- eral a v i a t i o n ogerations, w e ' r e r e a l l y mostly concerned with t h e l o c a l impact, l a r g e l y t h a t of carbon monoxide i n reasonably c l o s e proximity t o heavily used g e n e r a l a v i a t i o n a i r p o r t s . With regard t o t h e very v a l i d p o i n t s brought up by M r . H e l m s and discussed more completely yesterday on t e s t i n g and measurement problems, w e accept t h a t t h e s e have delayed work on a c t u a l reduction of engine emissions. Since t h e s e s s i o n yester- W e w i l l make an e f f o r t day, t h e FAA and myself have t a l k e d t h i s over- t o g e t a meaningful industry/government group t o work on t h i s within t h e n e x t several weeks. The SAE committee I referred to yesterday is scheduled t o meet w i t h i n 2 weeks. Our proposal I s to set up a subgroup t h a t would include t h e people who've spoken on t h i s subject h e r e dur- i n g t h e p a s t 2 days and t o work t o fill i n some of t h e gaps i n t h e pre- W e don't see t h i s as a formidable s e n t emissions measurement procedures.
problem, because of t h e e x c e l l e n t base t h a t now exists as a r e s u l t of your 3 years of experience. One comment on engine c o s t . This morning's session w a s t h e f i r s t exposure I ' d had t o a c t u a l c o s t estimates as t o t h i s program f o r t h e very wide a r r a y of engine models implementation of T do f e e l , i n a somewhat and a i r c r a f t types t h a t you have t o d e a l with.
t h a t s i n c e t h e approaches t h a t have been t a l k e d about most defensive way, s e r i o u s l y f o r use i n meeting t h e standards do r e s u l t i n f u e l economy b e n e f i t s as w e l l , t h a t t h e c o s t s of t h e t o t a l program can be spread over t h e presumed f u e l economy advantages t o your customers as w e l l as t o a i r q u a l i t y c o n t r o l . You s a i d it t h e o t h e r way around i n your pre- It's e q u a l l y v a l i d e i t h e r way. One o t h e r comment t h a t r e a l l y s e n t a t i o n .
wasn't brought o u t by M r . H e l m s , but did come o u t t h i s morning, has t o do w i t h Q l d engines and o l d a i r c r a f t . I should have s a i d t h i s morning that: w e have t h i s comment i n hand from t h e t u r b i n e engine manufacturing segment of t h e industry. It w a s presented a t our public hearings on t h i s subject in February 1976. We have to respond to I t . But engines that to are likely to be made in relatively lhited quantities in the future serve for replacement purposes in existing old design aircraft will have, presumably, minimum impact on air quality and justify some sort of exemp- tion or delay or something of that nature. 1 can assure you that this is being worked on.
This concludes the formal presentation of OUT COMMENT - G. Banerian: program. As all of you know, the purpose of the meeting wasn't to de- bate the merits of the regulations, but to provide data for future regu- 1 want latory action and petitioning for change if deemed necessary, to thank all of you for participating as you did and presenting your I, also, thank the Lewis Research material in a most professional way.
Center for a good job in arranging this meeting. A s you know, the action items for regulatory action are with FAA and EPA and not with NASA. We'll do what we can to assist them, but the initiative is with them.