Aviation Safety: FAA Near Midair Collision Reports

This report discusses the minimum separation distance in a near midair collision report which the event must meet in order to be classified a "near miss." If a pilot of flight crew member subjectively believes that the near miss occurred, the report of that event is accepted by the Federal Aviation Administration (FAA) and counts as a near miss in the FAA data base regardless of the actual separation distance. While no proximity limits are placed on near midair collision reports, the agency does attempt to categorize each reported encounter by degree of hazard represented from an aviation safety perspective.

CRS REPORT FOR CONGRESS AVIATION SAFETY: FAA NEAR MIDAIR COLLISION REPORTS J . Glen Moore S p e c i a l i s t i n S c i e n c e and T e c h n o l o g y Science Policy Research Division August 13, 1987 T h e Congressional Research Service works exclusivelv for the Congress. conducting research, analyzing legislation, a n d providing information at the request of committees, >fernhers. and their staffs. T h e Service makes such research available, without partisan bias, in tnanv forms including studies, reports, compilations, digests. and background briefings. L'pon request. CRS assists committees in analyzing legislati\.e proposals a n d issues, and in assessing the possible effects of these proposals and their alternati\-es. T h e Service's senior specialists a n d subject analysts are also available for personal consultations in their respective fields of expertise. .................................................................. 1985 CHANGE I N F A A ' s R E P O R T I N G PROCEDURE .................................. COMPARING PRE- AND P O S T - 1 9 8 5 DATA ........................................ NEAR M I D A I R C O L L I S I O N REPORT S T A T I S T I C S ................................... NEAR M I D A I R C O L L I S I O N R E P O R T S AND SYSTEM S A F E T Y ........................... ABSTRACT iii 1 3 4 6 AVIATION SAFETY: FAA NEAR MIDAIR COLLISION REPORTS A n e a r m i d a i r c o l l i s i o n r e p o r t i s a r e p o r t f i l e d by a p i l o t o r f l i g h t c r e w member o f a convnercial ( a i r c a r r i e r , a i r t a x i , o r commuter), m i l i t a r y o r general aviation a i r c r a f t , s t a t i n g t h a t a near midair c o l l i s i o n has occurred. T h e r e i s no minimum s e p a r a t i o n d i s t a n c e which t h e e v e n t must meet i n o r d e r t o by c l a s s i f i e d a s a " n e a r miss." I f a p i l o t of f l i g h t crew member s u b j e c t i v e l y b e l i e v e s t h a t a n e a r m i s s o c c u r r e d , t h e r e p o r t o f t h a t e v e n t i s a c c e p t e d by t h e F e d e r a l A v i a t i o n A d m i n s t r a t i o n (FAA) and c o u n t e d a s a n e a r miss i n t h e FAA d a t a b a s e r e g a r d l e s s of t h e a c t u a l s e p a r a t i o n d i s t a n c e . While n o p r o x i m i t y l i m i t s a r e p l a c e d on n e a r m i d a i r c o l l i s i o n r e p o r t s , t h e a g e n c y d o e s a t t e m p t t o c a t e g o r i z e e a c h r e p o r t e d e n c o u n t e r by d e g r e e of h a z a r d r e p r e s e n t e d from a n a v i a t i o n s a f e t y p e r s p e c t i v e . A " c r i t i c a l " n e a r miss i s one i n which t h e r e i s l e s s t h a n 100 f e e t o f s e p a r a t i o n between two a r c r a f t . II A p o t e n t i a l " n e a r miss i s one i n which a c o l l i s i o n would p r o b a b l y h a v e r e s u l t e d i f n o a c t i o n had been t a k e n by e i t h e r p i l o t . T h i s would u s u a l l y i n v o l v e a s e p a r a t i o n o f no l e s s t h a n 500 f e e t between a i r c r a f t . Reports a r e c l a s s i f i e d a s "no h a z a r d " when d i r e c t i o n and a l t i t u d e would h a v e made a m i d a i r c o l l i s i o n i m p r o b a b l e r e g a r d l e s s of e v a s i v e a c t i o n t a k e by a p i l o t . 1985 CHANGE IN FAA'S REPORTING PROCEDURE The s u b j e c t i v e n a t u r e o f n e a r m i d a i r c o l l i s i o n r e p o r t s makes t h e i r v a l u e a s a m e a s u r e o f s y s t e m s a f e t y somewhat s u s p e c t . s t r i k e and s u b s e q u e n t f i r i n g o f t h r e e - f o u r t h s Nevertheless, following t h e of t h e a i r t r a f f i c c o n t r o l l e r work f o r c e i n 1981, t h e FAA f r e q u e n t l y c i t e d a d e c l i n i n g number of n e a r m i d a i r c o l l i s i o n r e p o r t s a s a n i n d i c a t i o n t h a t t h e a i r t r a n s p o r t a t i o n s y s t e m was a s s a f e o r s a f e r than before the s t r i k e . S k e p t i c a l of t h e agency's c l a i m s , t h e A v i a t i o n Consumer A c t i o n P r o j e c t o b t a i n e d raw f i e l d r e p o r t s of n e a r m i d a i r c o l l i s i o n s u n d e r t h e Freedom o f I n f o r m a t i o n Act. I n a s a m p l i n g of j u s t t h r e e of FAA's n i n e r e g i o n s , i t found a s i g n i f i c a n t number o f n e a r c o l l i s i o n s t h a t were s i m p l y n o t put i n t o t h e d a t a b a s e . l The P r o j e c t p r o v e d , and FAA l a t e r acknowledged, t h a t t h e number of n e a r m i s s e s , r a t h e r t h a n d e c l i n i n g , had been rising steadily since the controllers' strike. P r i o r t o 1985, t h e FAA n e a r m i d a i r c o l l i s i o n d a t a b a s e c o n t a i n e d o n l y d a t a on n e a r m i d a i r c o l l i s i o n r e p o r t s t h a t had been i n v e s t i g a t e d by t h e a g e n c y ' s f l i g h t standards inspectors. P r e l i m i n a r y f i e l d r e p o r t s had t o b e f o r w a r d e d t o FAA h e a d q u a r t e r s i n Washington, b u t were n o t l o g g e d i n t o t h e n e a r c o l l i s i o n d a t a b a s e u n t i l a f t e r t h e y had been i n v e s t i g a t e d . built-in C o n s e q u e n t l y , t h e r e was a l a g time f o r each i n c i d e n t e n t e r e d i n t o t h e d a t a base. Following t h e A v i a t i o n Consumer A c t i o n P r o j e c t d i s c l o s u r e , t h e FAA c o n d u c t e d i t s own i n v e s t i g a t i o n and d i s c o v e r e d t h a t n o t o n l y were some p r e l i m i n a r y r e p o r t s n o t being investigated--and t h e r e f o r e n o t g e t t i n g i n t o t h e d a t a base--but t h a t some p r e l i m i n a r y r e p o r t s were n o t g e t t i n g t o FAA h e a d q u a r t e r s . R e c o g n i z i n g t h e i m p o r t a n c e of a c o m p l e t e d a t a b a s e , FAA a d m i n i s t r a t o r Donald Engen i n i t i a t e d a new p r o c e d u r e i n J a n u a r y 1985, r e q u i r i n g a l l p r e l i m i n a r y r e p o r t s of n e a r m i d a i r c o l l i s i o n s be f o r w a r d e d a s soon a s p o s s i b l e t o Washington t o a c e n t r a l p o i n t and logged i n t o t h e d a t a s y s t e m upon r e c e i p t . Each r e p o r t i s t h e n r e q u i r e d t o be i n v e s t i g a t e d w i t h i n 90 d a y s o f r e c e i p t . The new p r o c e d u r e s a l l o w FAA t o a c c e s s r e a l t i m e d a t a on p r e l i m i n a r y and c o m p l e t e d near midair c o l l i s i o n investigation reports as i t continues t o investigate each 1 Consumer Group F a u l t s Near-miss F i g u r e s . T e c h n o l o g y , Feb. 1 1 , 1985. A v i a t i o n Week and S p a c e reported n e a r miss. The p r i m a r y b e n e f i t s of t h e c h a n g e i n p r o c e d u r e a r e t h a t c u r r e n t numbers of n e a r m i d a i r c o l l i s i o n r e p o r t s a r e r e a d i l y a v a i l a b l e and t h a t a l l p r e l i m i n a r y r e p o r t s a r e c o n t a i n e d i n one d a t a b a s e , making i t l e s s l i k e l y Eor d a t a d i s c r e p a n c i e s t o o c c u r i n t h e f u t u r e . 2 COMPARING PRE- AND POST-1985 DATA B e g i n n i n g w i t h 1985 d a t a , t h e FAA n e a r m i d a i r c o l l i s i o n s t a t i s t i c s may i n c l u d e r e p o r t s of a i r t r a f f i c c o n t r o l o p e r a t i o n a l e r r o r s and p i l o t d e v i a t i o n s from a i r t r a f f i c c o n t r o l i n s t r u c t i o n s , when t h e y r e s u l t i n s e p a r a t i o n s o f l e s s t h a n 500 f e e t . I n 1985 t h e r e were a t o t a l o f 777 r e p o r t e d n e a r c o l l i s i o n s , o f which 758 a r e from p i l o t o r crew member r e p o r t s , 12 a r e from a i r t r a f f i c c o n t r o l o p e r a t i o n a l e r r o r r e p o r t s , and 7 a r e from p i l o t d e v i a t i o n r e p o r t s . The number o f n e a r m i s s e s r e s u l t i n g from o p e r a t i o n a l e r r o r s and p i l o t d e v i a t i o n s i n 1986 i s 12 and 1 5 , r e s p e c t i v e l y ; p r e l i m i n a r y c o u n t i s 12 and 4 , r e s p e c t i v e l y . t h r o u g h J u n e 3 0 , 1 9 8 7 , FAA's T a b l e s 1 and 2 o n page 5 o f t h i s r e p o r t show p i l o t - r e p o r t e d n e a r m i d a i r c o l l i s i o n s . Near m i s s e s r e s u l t i n g f r o m o p e r a t i o n a l e r r o r s o r p i l o t d e v i a t i o n s a r e n o t i n c l u d e d b e c a u s e t h e FAA d o e s n o t c a t e g o r i z e them. A l s o , s i n c e t h e FAA changed p r o c e d u r e s and g a v e new e m p h a s i s t o r e p o r t i n g n e a r m i d a i r c o l l i s i o n s i n 1985, i t i n s i s t s t h a t p r e - and post-1985 d a t a a r e n o t comparable. D e l e t i n g o p e r a t i o n a l e r r o r s and p i l o t d e v i a t i o n s from t h e 1985-1987 s t a t i s t i c s improves t h e i r c o m p a r a b i l i t y w i t h p r i o r years. U.S. C o n g r e s s . House. Committee on P u b l i c Works and T r a n s p o r t a t i o n . Subcommittee on I n v e s t i g a t i o n s and O v e r s i g h t . Near M i d a i r C o l l i s i o n s . H e a r i n g s , 9 9 t h Cong., 1 s t S e s s . J u n e 26, 1985. S t a t e m e n t o f Donald D. Engen, A d m i n i s t r a t o r , FAA. NEAR M I D A I R COLLISION REPORT STATISTICS F o l l o w i n g t h e a d o p t i o n of new r e p o r t i n g p r o c e d u r e s i n J a n u a r y 1 9 8 5 , t h e a g e n c y d e c i d e d t h a t i t had s u b s t a n t i a l l y u n d e r r e p o r t e d t h e number of n e a r misses i n i t i a l l y r e p o r t e d f o r 1983 and 1984. The agency s u b s e q u e n t l y r e v i s e d t h e 1983 f i g u r e s upward t o 475 from t h e 286 e a r l i e r r e p o r t e d , and t h e number o f r e p o r t e d n e a r m i s s e s i n 1984 was r a i s e d t o 589 from 299. A s t a b l e 1 shows, t h e number o f n e a r m i d a i r c o l l i s i o n r e p o r t s h a s i n c r e a s e d a n n u a l l y i n e v e r y y e a r s i n c e 1982. The t a b l e a l s o shows a r i s i n g t r e n d between 1982 and 1987 i n t h e number o f n e a r m i d a i r c o l l i s i o n r e p o r t s i n v o l v i n g c o m e r c i a l a i r c r a f t . The N a t i o n a l T r a n s p o r t a t i o n S a f e t y Board i s d i s t u r b e d by a r i s i n g t r e n d i n c r i t i c a l n e a r m i d a i r c o l l i s i o n s involving comnercial a i r c r a f t ( t a b l e 21, c a l l i n g t h e 33 p e r c e n t i n c r e a s e i n 1986 ( 4 8 ) o v e r 1985 ( 3 6 ) "most . s i g n i f i c a n t "3 U n l i k e many r e p o r t e d e n c o u n t e r s , presumably t h e s e a i r c r a f t w e r e under t h e d i r e c t c o n t r o l o f t h e a i r t r a f f i c c o n t r o l s y s t e m which i s s u p p o s e d t o p r o t e c t them from such e n c o u n t e r s . C o n s e q u e n t l y , an i n c r e a s e i n t h e s e e n c o u n t e r s c o u l d be a n i n d i c a t i o n of a d e t e r i o r a t i n g a b i l i t y i n t h e a i r t r a f f i c c o n t r o l system t o provide e f f e c t i v e s e p a r a t i o n . The r i s e i n c r i t i c a l n e a r m i s s e s i n v o l v i n g commercial a i r c r a f t was o n e o f s e v e r a l f a c t o r s c o n s i d e r e d i n t h e ~ o a r d ' sMay 1 3 , 1987, r e c o r n e n d a t i o n t o t h e FAA t o r e d u c e t r a f f i c i n t h e a i r s p a c e system t h i s ~ u m n e r . ~ S a f e t y Recommendation A-87-52 S a f e t y Board, May 1 3 , 1987. Ibid. Through -55. National Transportation TABLE 1. P i l ~ t - R e p o r t e d Near M i d a i r C o l l i s i o n R e p o r t s Year NOTE: Tot a 1 Number Critical Percent Critical A i r l i n e r d e n o t e s a l l commercial c a t e g o r i e s ( a i r l i n e r , a i r t a x i and commuter). P i l o t d e v i a t i o n and c o n t r o l l e r o p e r a t i o n a l e r r o r r e p o r t s h a v e been dropped from 1985-1987 s t a t i s t i c s f o r t h e p u r p o s e o f comparability with prior-year s t a t i s t i c s . SOURCE: TABLE. 2. r r a f f i c : t h e P a i n of ~ e g r o w t h , " 1973-1982 FAA from a n a r t i c l e , " ~ i T by Douglas B. F e a v e r . The Washington P o s t , May 29, 1983. 1983-1987 FAA, A v i a t i o n S a f e t y D i v i s i o n . Pilot-Reported Year SOURCE: Airliner Involved Near M i d a i r C o l l i s i o n R e p o r t s I n v o l v i n g A i r l i n e r s A i r 1iner Involved FAA, A v i a t i o n S a f e t y D i v i s i o n . Number Critical Percent Critical NEAR M I D A I R COLLISION REPORTS AND SYSTEM SAFETY The s t e a d y r i s e i n n e a r m i d a i r c o l l i s i o n r e p o r t s h a s r e c e i v e d h e i g h t e n e d media a t t e n t i o n i n r e c e n t months a s an i n d i c a t i o n t h a t s a f e t y i n t h e U.S. t r a n s p o r t a t i o n s y s t e m i s on t h e d e c l i n e . air However, s a f e t y s p e c i a l i s t s g e n e r a l l y a g r e e t h a t n e a r miss s t a t i s t i c s a r e n o t a p a r t i c u l a r l y good measure of a i r s a f e t y o r r i s k b e c a u s e o f t h e i r s u b j e c t i v e n a t u r e and b e c a u s e t h e y u s u a l l y f a i l t o d i s t i n g u i s h between n e a r - c a t a s t r o p h i c a c t u a l danger. i n c i d e n t s and t h o s e which posed l i t t l e I n a d d i t i o n , t h e r i s e i n n e a r m i s s r e p o r t s may n o t b e a d i r e c t i n d i c a t i o n o f t h e p e r f o r m a n c e of t h e a i r t r a f f i c c o n t r o l s y s t e m s i n c e many e n c o u n t e r s i n v o l v e v i s u a l f l i g h t r u l e s (VFR) t r a f f i c n o t u n d e r t h e c o n t r o l o f an a i r t r a f f i c c o n t r o l l e r . The FAA n o t e s t h a t t h e r e i s no s t a t i s t i c a l c o r r e l a t i o n between n e a r m i d a i r c o l l i s i o n r e p o r t s and a c t u a l c o l l i s i o n s . For i n s t a n c e , t h e 24 m i d a i r c o l l i s i o n s i n 1985, none o f which i n v o l v e d a i r c a r r i e r a i r c r a f t , was t h e s e c o n d l o w e s t t o t a l i n 20 y e a r s . N e v e r t h e l e s s , t h e r e d o e s seem t o be a c o r r e l a t i o n between t h e r i s e i n a i r t r a f f i c and t h e r i s e i n n e a r m i s s r e p o r t s . With commercial a i r t r a f f i c e x p e c t e d t o grow a t a r a t e of a b o u t f i v e p e r c e n t p e r y e a r f o r t h e r e m a i n d e r o f t h e 2 0 t h c e n t u r y , t h e number of n e a r m i s s r e p o r t s could r i s e accordingly i f t h i s c o r r e l a t i o n holds.