Midair collision, Hughes Air West DC

Midair collision, Hughes Air West DC-9, N9345, and U. S. Marine Corps F4B, 151458 Near Duarte, California, June 6, 1971
Micro-summary: A midair collision between a DC-9 and F-4 results in the
destruction of both airplanes.
Event Date: 1971-06-06 at 1811 PDT
Investigative Body: National Transportation Safety Board (NTSB), USA
Investigative Body's Web Site: http://www.ntsb.gov/
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www.fss.aero
SA-426
File No. 1-0005
AIRCRAFT ACCIDENT REPORT
HUGHES AIR WEST DC-9, N9345
AND U.S. MARINE CORPS F-4B, 151458
NEAR DUARTE, CALIFORNIA
JUNE 6, 1971
ADOPTED: AUGUST 30, 1972
>Â¥
NATIONAL TRANSPORTATION SAFETY BOARD
Washington, D. C. 20591
REPORT NUMBER: NTSB-AAR-72-26
TABLE OF CONTENTS
Synopsis
,
. . .. .. . . .. . -. .. . .- .a
-. . . .. .. .. . .
. . .. .. .. .. .. . .....,
. .. .- ......
. - -. .. .. -. . .. ... ... ..
Investigation
a
History of t h e Flight
Injuries to Persons
*
Damaqe -to A i r c r a f t
- - - - - .
Other Damage
Crew Information
Aircraft Information a
Meteorological ~nformation
Aids to Navigation
~ommunications
Aerodrome and Ground F a c i l i t i e s
Flight Recorders
Wreckage
Fire
Survival Aspects
*
T e s t s and Research
a
a
-
e
. .. . . . .. . .
...........
.
. .. . . .. . .. -. .. ..
.
. . .- ..
. . . . .. -. ..-. .. .
. . . . . . . . ...
.
.
Other
A n a l y s i s and Conclusions
Analysis
.
a
.
m
Conclusions
.
(a) Findings
a
(b) Probable Cause
Recommendations
Footnotes
.
.
.
a
.
Appendices
Appendix A
Appendix 3
Appendix C
Attachments
Attachment 1
Attachment 2
Attachment 3
Attachment 4
.
.
*
*
a
.
- Collision Area
- and Closure
Ranges,
Computed
- Visibility
- Visibility
1
3
3
6
6
6
6
6
6
7
8
8
8
9
10
10
11
14
14
14
25
25
27
27
32
34
35
37
Bearings
Bates
Chart DC-9
Chart F-4B
F i l e No.
1-0005
NATIONAL TRANSPORTATION SAFETY BOARE
WASHINGTON, D. C. 20591
AIRCRAFT ACCIDENT EEFORT
September 22, 1 9 7 2
---------------------------------------------------------------------------------------------------------------------------
Adopted:
HUGHES A I R WEST DC-9, N9345, AND
S. MARINE CCRPS F-4E, 151458
NEAR DUARTE, CALIFCRNIA
J U N E 6, 1971
U.
SYNOPSIS
A Huqhes A i r Hest DC-9, N9345, and a U. S. Marine Corps
I-4B,
Bureau No.
151458, c o l l i d e d i n f l i g h t n e a r Duarte,
C a l i f o r n i a , a t approximately 1811 P.d.t..
J u n e 6, 1971.
All
4 9 o c c u p a n t s , 44 p a s s e n g e r s and f i v e crewmembers, aboard t h e
CC-9, and t h e p i l o t of t h e F-4B were f a t a l l y i n j u r e d .
The
r a d a r i n t e r c e p t o f f i c e r , t h e o n l y o t h e r occupant i n t h e F4 B , e j e c t e d from t h e a i r c r a f t a f t e r t h e c o l l i s i o n and
H e was n o t i n j u r e d .
Both
parachuted t o t h e ground.
a i r c r a f t were d e s t r o y e d by t h e c o l l i s i o n , ground impact, and
fire.
The Huqhes A i r west DC-9 w a s under r a d a r c o n t r o l of t h e
Los Angeles A i r Route T r a f f i c C o n t r o l C e n t e r , c l i m b i n g t o
F l i q h t Level 330.
The F-4B was b e i n g flown a t a p p r o x i m a t e l y
en
15,500 f e e t , i n accordance w i t h V i s u a l F l i g h t Rules,
r o u t e t o t h e Marine Corps A i r S t a t i o n , E l Toro, C a l i f o r n i a .
The c o l l i s i o n o c c u r r e d a t a n a l t i t u d e of a p p r o x i m a t e l y
15,150 f e e t .
The v i s i b i l i t y i n t h e area, a t t h e t i m e o f t h e a c c i d e n t ,
qood and t h e r e were no c l o u d s between t h e t w o a i r c r a f t
d u r i n g t h e f i n a l minutes o f f l i q h t .
was
The National T r a n s p o r t a t i o n S a f e t y Board determines t h a t
the probable cause of this a c c i d e n t was t h e f a i l u r e of both
crews t o see and avoid each o t h e r b u t recognizes t h a t t h e y
had only marginal c a p a b i l i t y t o d e t e c t , a s s e s s , and avoid
t h e collision.
Other c a u s a l f a c t o r s i n c l u d e a very high
c l o s u r e r a t e , comingling of IFR and VFR t r a f f i c i n an a r e a
where t h e l i m i t a t i o n of t h e ATC system precludes e f f e c t i v e
s e p a r a t i o n of such t r a f f i c , and f a i l u r e of t h e crew of
BuNo458 t o r e q u e s t r a d a r a d v i s o r y s e r v i c e , p a r t i c u l a r l y
considering t h e f a c t
that
they
had
an
inoperable
transponder.
A s a result of t h i s a c c i d e n t t h e S a f e t y ~ o a r drecommends
t h a t t h e F e d e r a l Aviation Administration:
(1) i n s t a l l video
t a p e on a l l r a d a r d i s p l a y s and "area" microphones i n a i r
t r a f f i c control f a c i l i t i e s ;
(2) provide p o s i t i v e c o n t r o l
a i r s p a c e from t a k e o f f t o l a n d i n g f o r a l l IFR t r a f f i c ; and
(3) i n s u r e t h a t a l l r a d a r f a c i l i t i e s are capable
of
r e c e i v i n g Code 7700, and e s t a b l i s h d e f i n i t i v e procedures f o r
t h e handling of such t r a f f i c .
The S a f e t y Board a l s o recommended t h a t t h e Federal
Aviation Administration and t h e Department of
Defense
c o o p e r a t i v e l y develop a program t o inform a l l a i r s p a c e u s e r s
of
t h e heaviest t r a f f i c areas.
I n a d d i t i o n , it was
recommended t h a t t h e Department of Defense:
(1) restrict
hiqh-speed,
low-level o p e r a t i o n s t o designated a r e a s and
(2) d e l i n e a t e e x p l i c i t circumstances where t h e
routes:
10,000 f e e t / 2 5 0 k n o t s l i m i t a t i o n may be exceeded;
(3)
c o n s i d e r usinq a i r i n t e r c e p t r a d a r f o r c o l l i s i o n avoidance
purposes:
and (4) p u b l i c i z e the a v a i l a b i l i t y of the FAA
Radar Advisory S e r v i c e and c o n s i d e r making t h e use of t h i s
s e r v i c e mandatory.
1
1.1
INVESTIGATION
H i s t o r v of t h e F l i u h t
Hughes A i r West F l i g h t 706 (RW706) was a r e g u l a r l y
s c h e d u l e d f l i g h t from L o s Angeles, C a l i f o r n i a ,
t o Seattle,
Washinqton, w i t h i n t e r m e d i a t e s t o p s a t S a l t Lake C i t y , Utah,
E o i s e and Lewiston, Idaho, and Pasco and Yakima, Washington.
The f l i g h t d e p a r t e d Los Angeles I n t e r n a t i o n a l A i r p o r t a t
1802 A/
and,
f o l l o w i n g r a d a r v e c t o r s from Los Angeles
D e p a r t u r e C o n t r o l , c o n t a c t e d t h e Los Angeles A i r Route
I n accordance w i t h
T r a f f i c C o n t r o l C e n t e r (ARTCC) a t 1806.
a r e q u e s t , t h e f l i g h t r e p o r t e d l e a v i n g 12,000 f e e t a t 1809,
and t h e c o n t r o l l e r a d v i s e d , " A i r West s e v e n z e r o s i x red,
t u r n l e f t heading z e r o f o u r z e r o u n t i l r e c e i v i n g Daggett
proceed d i r e c t . "
RW706 acknowledged, "OK,
zero four zero
d i r e c t , t o Daqqett.@g T h i s was t h e l a s t r e c o r d e d t r a n s m i s s i o n
from t h e f l i g h t .
The U. S. Marine Corps F-4B, Bureau No. 151458 (BuNo458)
d e p a r t e d t h e Marine Corps A i r S t a t i o n (MCAS) E l Toro,
C a l i f o r n i a , on J u n e 4, 1971, as p a r t of a f l i g h t o f t w o
aircraft.
The f l i g h t w a s s c h e d u l e d f o r a n o v e r n i g h t crossc o u n t r y t o McChord A i r Force B a s e (AFB),
Washington,
and
return.
McClellan AFB, C a l i f o r n i a , was t o b e used f o r
r e f u e l i n q northbound, and Mountain Home AFE, Idaho, w a s t o
be used southbound.
Although t h e t r a n s p o n d e r s on b o t h
a i r c r a f t a p p a r e n t l y f a i l e d s h o r t l y a f t e r d e p a r t u r e from MCAS
E l Toro, t h e f l i q h t of two w a s p e r m i t t e d t o proceed t o
McChord AFE under c o n t r o l o f the ATC System ky r a d a r .
On
J u n e 5, t h e f l i q h t c o n t i n u e d t o Mountain H o m e AFB, b u t t h e
r a d i o i n BuNo458 f a i l e d d u r i n g t h e l a n d i n g approach.
After
l a n d i n g , t h e crews d i s c u s s e d t h e o p e r a t i o n a l s t a t u s of t h e
two a i r c r a f t , and t h e f l i g h t l e a d e r d e c i d e d t h a t h e would
The winqman and h i s Radar
proceed t o MCAS E l Toro.
I n t e r c e p t O f f i c e r (RIO) were i n s t r u c t e d t o a w a i t r e p a i r s t o
EuNo458 and t h e n r e t u r n t o MCAS E l Toro.
The mechanical
d i f f i c u l t i e s w i t h t h e a i r c r a f t a t t h i s time included:
1.
Inoperative transponder
2.
Inoperative radio
3.
Oxygen system l e a k
4.
Degraded r a d a r system
Maintenance personnel a t Mountain Home AFB replaced a f u s e
t o f i x t h e r a d i o , b u t t h e y d i d n o t have t h e personnel t o
check t h e transponder. They confirmed t h e oxygen leak, but
could n o t r e p a i r it. No a t t e m p t was made t o r e s t o r e t h e
r a d a r t o peak performance a t t h a t time.
The crew of BuNo458 f i l e d a Visual F l i g h t Rules (VFR)
f l i g h t plan t o Naval A u x i l i a r y A i r S t a t i o n (NAAS) Fallon,
Nevada, below t h e A r e a P o s i t i v e Control (APC), 2/ because of
t h e i n o p e r a t i v e transponder and f u e l requirements. On t h i s
l e g o f t h e f l i g h t t h e oxygen l e a k increased, and t h e oxygen
was t u r n e d o f f s h o r t l y a f t e r t a k e o f f from Mountain Home AFB.
The maintenance personnel on d u t y a t NAAS F a l l o n were unable
t o provide t h e a p p r o p r i a t e r e p a i r s , s o t h e p i l o t contacted
h i s squadron d u t y o f f i c e r f o r i n s t r u c t i o n s .
H e was advised
t o proceed t o MCAS E l Tor0 a t low a l t i t u d e .
A f t e r r e f u e l i n g , t h e crew a g a i n f i l e d a VFE f l i g h t plan
The t a k e o f f was delayed from 1400 t o 1716
below APC.
because MCAS E l Toro was c l o s e d f o r an airshow between 1400
and 1630. The intended r o u t e of f l i g h t was d i r e c t Fresno,
J-65 B a k e r s f i e l d , J-5 10s Angeles, d i r e c t MCAS E l Toro. The
f l i g h t departed a t 1716, climbed i n i t i a l l y t c 7,500 f e e t ,
and t h e n climbed to 15,500 f e e t t o c l e a r mountains and some
c l o u d s approximately 50 miles from NAAS Fallon. A f t e r
c r o s s i n g t h e mountains, t h e y descended t o 5,500 f e e t and
remained a t t h a t a l t i t u d e u n t i l they reached Bakersfield.
Approximately 15 miles n o r t h of t h e B a k e r s f i e l d F l i g h t
S e r v i c e S t a t i o n a p o s i t i o n r e p o r t was made, and t h e MCAS E l
Toro weather was checked. The crew a l s o decided t o d e v i a t e
from t h e o r i g i n a l p l a n a t t h i s point.
They flew e a s t of t h e
planned course, over Palmdale, t o avoid t h e a n t i c i p a t e d
heavy t r a f f i c over L o s Angeles.
The f l i g h t continued i n a low p r o f i l e , minimum a l t i t u d e
1,000 f e e t above t h e ground, u n t i l approximately 15 miles
northwest of Palmdale.
Due t o d e t e r i o r a t i n g v i s i b i l i t y ,
t h e y again climbed t o 15,500 f e e t .
The R I O s t a t e d t h a t t h e
climfc was made, using maximum enqine
power,
without
a f t e r b u r n e r , and t o o k less t h a n 2 minutes.
Shortly a f t e r
l e v e l - o f f . t h e Distance Measurina Eauicment fEMEt f e a t u r e of
t h e VORTAC 3/ i n d i c a t e d 50 miles t o MCAS E l
The p i l o t
executed a 3600 a i l e r o n r o l l a t t h i s time, which took
approximately 3 seconds t o complete. The R I O e s t i m a t e d t h a t
t h e t r u e a i r s p e e d i n t h e climb and a f t e r l e v e l - o f f was 420
knots, and t h a t t h e c o l l i s i o n occurred approximately 1
minute and 20 seconds a f t e r t h e r o l l .
During most o f t h i s
ore.
p e r i o d , he was o p e r a t i n g t h e r a d a r i n t h e mapping mode, b u t ,
due t o t h e
extremely
degraded
air-to-air
detection
c a p a b i l i t y , no a i r b o r n e t a r g e t s were seen.
Since t h e
r a d a r s c o p e was i n t h e stowed p o s i t i o n , t h e R I O w a s l e a n i n g
forward, and h i s l i n e o f s i g h t w a s d i r e c t e d downward a t
a p p r o x i m a t e l y a 450 a n g l e w h i l e u s i n g t h e r a d a r s c o p e .
Approximately 3 t o 10 seconds p r i o r t o c o l l i s i o n , t h e R I O
r a i s e d h i s head, observed t h e DC-9 i n h i s p e r i p h e r a l v i s i o n
approximately 500 t o t h e r i g h t and s l i g h t l y b e n e a t h h i s
a i r c r a f t . H e s h o u t e d t o t h e p i l o t , b u t t h e p i l o t had
i n i t i a t e d an e v a s i v e r o l l b e f o r e t h e R I O f i n i s h e d t h e
H e d i d n o t see RW706 t a k e any e v a s i v e a c t i o n .
warning.
A f t e r t a k e o f f from Los Angeles, RW706 was q i v e n two
r a d a r t r a f f i c a d v i s o r i e s by d e p a r t u r e c o n t r o l , and c o n t r o l
was s u b s e q u e n t l y t r a n s f e r r e d t o t h e R-18 s e c t o r o f Los
Anqeles ARTCC.
The d a t a and r a d a r p o s i t i o n s o f t h i s s e c t o r
were manned by developmental c o n t r o l l e r s 4/, e a c h of whom
was
beinq
supervised
by
a
journeyman
controller.
Consequently, f o u r i n d i v i d u a l s were o b s e r v i n g t h e r a d a r s c o p e
a t t h e R-18 p o s i t i o n p r i o r t o t h e c o l l i s i o n .
They a l l
a g r e e d t h a t no primary t a r g e t s were observed i n p r o x i m i t y t o
RW706 a t any time. F i v e t r a f f i c a d v i s o r i e s were g i v e n t o
o t h e r a i r c r a f t i n t h e R-18 sector i n t h e 6-minute timespan
prior t o the collision.
A f t e r t h e c o l l i s i o n , BuNo458 began t o tumble v i o l e n t l y
a b o u t t h e l a t e r a l a x i s . The R I O w a i t e d a b o u t 5 seconds,
and, a f t e r s e e i n g numerous warning l i q h t s i n t h e c o c k p i t , he
e j e c t e d from t h e a i r c r a f t .
The e j e c t i o n was s u c c e s s f u l , and
he p a r a c h u t e d t o t h e ground w i t h o u t i n j u r y .
W i t n e s s e s i n t h e a r e a of t h e a c c i d e n t gave w i d e l y
varying accounts of t h e c o l l i s i o n .
Thirty-four witnesses
saw o r h e a r d jet a i r c r a f t p r i o r t o t h e c o l l i s i o n , and 24
p e r s o n s observed t h e two a i r c r a f t on c o n v e r g i n g c o u r s e s .
F i f t e e n p e r s o n s saw a f i g h t e r a i r c r a f t i n a r o l l i n g o r
e v a s i v e maneuver p r i o r t o c o l l i s i o n . T h r e e p e r s o n s on t h e
ground and two p i l o t s , a t v a r y i n g d i s t a n c e s from t h e
immediate c o l l i s i o n area, o b s e r v e d a f i g h t e r
aircraft
p r o c e e d i n g a l o n g t h e r o u t e o f f l i g h t d e s c r i b e d by t h e R I O .
(See Attachment 1.)
Several witnesses i n t h e area of the
c o l l i s i o n r e p o r t e d s e e i n g a f i g h t e r a i r c r a f t d o i n g r o l l s and
c i r c l i n g i n t h e area.
1.2
Injuries to Persons
w-
Iniuries
Others
5
F a t a l EC-9
-4B
N o n f a t a l DC-9
F-4B
None DC-9
F- 4B
1.3
Fassenaer s
1
0
0
0
1
Damaae t o a i r c r a f t
Both a i r c r a f t were d e s t r o y e d by t h e c o l l i s i o n , ground
impact, and s u b s e q u e n t f i r e .
1.4
O t h e r Damaae
Both a i r c r a f t c r a s h e d i n a remote mountainous area, and
a l l ground damage w a s r e s t r i c t e d t o underbrush which w a s
burned i n t h e ground f i r e .
1.5
Crew Information
The crews of
respective flights.
1.6
b o t h a i r c r a f t were q u a l i f i e d f o r t h e
(See A p ~ e n d i xE f o r d e t a i l s . )
A i r c r a f t Information
The DC-9 was p r o p e r l y c e r t i f i c a t e d and b o t h a i r c r a f t
had been m a i n t a i n e d i n accordance w i t h e x i s t i n g r e g u l a t i o n s .
The weight a n d c e n t e r o f g r a v i t y of e a c h were w i t h i n
The DC-9 was s e r v i c e d w i t h Jet A f u e l
prescribed l i m i t s .
and t h e E-4B w i t h JP-5 f u e l .
(See Appendix C f o r d e t a i l s . )
The weather i n t h e v i c i n i t y of t h e a c c i d e n t s i t e w a s
c h a r a c t e r i z e d by low-level haze and smoke, s c a t t e r e d low
c l o u d s and h i g h , t h i n , broken o r s c a t t e r e d clouds.
There
w a s no f r o n t a l weather i n t h e area.
The p e r t i n e n t p o r t i o n o f t h e a v i a t i o n area f o r e c a s t
i s s u e d by t h e N a t i o n a l Weather S e r v i c e a t Los Anqeles was i n
p a r t , as follows:
S c a t t e r e d , v a r i a b l e t o broken c l o u d s a t 23,000 f e e t ,
Coastal
v i s i b i l i t y 3 t o 6 miles, h a z e and smoke.
s t r a t u s i n c r e a s i n g and moving o n t o immediate coast 1900
t o 2100 t h e n s p r e a d i n g i n l a n d a b o u t 20 miles by
midnight w i t h h i g h e r c o a s t a l t e r r a i n
occasionally
obscured.
The Vandenberg AFB 1700 r a d i o s o n d e a s c e n t showed a
s h a l l o w l a y e r o f r e l a t i v e l y moist u n s t a b l e a i r n e a r t h e
s u r f a c e t o t h e b a s e o f a n 80 C., i n v e r s i o n n e a r 1,000 f e e t
w i t h t h e t o p n e a r 4,000 f e e t . The a s s o c i a t e d winds a l o f t
o b s e r v a t i o n was, i n p a r t , a s follows:
H e i a h t ( f e e t m.s.1.1
Direction P t r u e )
V e l o c i t y (knots)
Surface
1# 000
3,000
6,000
9,000
12,000
15.000
O f f i c i a l s u n s e t a t Los Angeles was a t 2002.
1.8
Aids . t o Naviqation
The L o s Angeles ARTCC u s e s t h r e e ARSR-1E r a d a r s y s t e m s
f o r t h e c o n t r o l of t r a f f i c .
Each o f t h e s e s y s t e m s h a s a
r a n q e o f a p p r o x i m a t e l y 150 m i l e s , and i s d i s p l a y e d a t t h e
c o n t r o l p o s i t i o n s on a n RBDE-5 h o r i z o n t a l s c a n c o n v e r t e r
w i t h a 21-inch c a t h o d e r a y tube.
The a n t e n n a e f o r t h e ABSR1E s y s t e m s r o t a t e a t 5 r.p.m.
A d d i t i o n a l l y , each s e c t o r h a s
a v e r t i c a l d i s p l a y which i s u s e d as a backup system, and a n
a i d i n r e c e i v i n g r a d a r handoffs.
The v e r t i c a l d i s p l a y i s
a l s o a n RBDE-5 s c a n c o n v e r t e r .
The R-18 sector c o n t r o l l e r a t t h e time of the a c c i d e n t
m o n i t o r i n g t h e San Pedro ARSR-1E
system
on
the
horizontal display.
T h i s i s a j o i n t - u s e system w i t h t h e
near
Long
Beach,
military.
The a n t e n n a is l o c a t e d
California.
The c o n t r o l s were a d j u s t e d t o t h e 55-mile
range, w i t h 5-mile r a n g e marks.
The d i s p l a y was o f f c e n t e r e d a p p r o x i m a t e l y 40 miles t o t h e southwest.
The
moving t a r g e t i n d i c a t o r (MTI) 51 w a s set a t l e v e l 4 , and t h e
s t a q q e r e d p u l s e r e p e t i t i o n f r e q u e n c y (PRF) c i r c u i t w a s
o p e r a t i n g .A/
was
The R-18 c o n t r o l l e r had t h e ASR-4 system s e l e c t e d on
t h e RBDE-5 Sector v e r t i c a l d i s p l a y . The ASR-4 antenna is
l o c a t e d a t Los Anqeles I n t e r n a t i o n a l A i r p o r t . and h a s a
r a n g e o f approximately 50 miles.
The r a t e o f a n t e n n a
r o t a t i o n is 12.75 r.p.m.
The R-36
sector c o n t r o l l e r was m o n i t o r i n g t h e Boron
AKSR-1E r a d a r system on t h e h o r i z o n t a l s c a n c o n v e r t e r a t t h e
time of t h e a c c i d e n t . The Boron a n t e n n a i s l o c a t e d i n t h e
v i c i n i t y o f Edwards AFB, C a l i f o r n i a .
The c o n t r c l l e r had t h e
He
San Pedro r a d a r system on the sector v e r t i c a l d i s p l a y .
had r a d a r - i d e n t i f i e d RW706 and w a s w a i t i n g f o r them t o c a l l
p r i o r t o assuming c o n t r o l r e s p o n s i b i l i t y .
E e observed a
t r a n s p o n d e r Code 7700 I / a p p e a r on h i s h o r i z o n t a l d i s p l a y
He
a p p r o x i m a t e l y 5 miles n o r t h w e s t of t h e marker f o r RW706.
a l s o h e a r d a n emergency beacon s i g n a l on t h e VHF Guard
H e d i d n o t see t h e Code
Channel 8/ which he was monitoring.
7700 on t h e v e r t i c a l d i s p l a y .
The Code 7700 t a r g e t appeared
a b o u t two sweeps b e f o r e t h e t a r g e t of RW706 disappeared.
The Code 7700 t h e n moved in a wide, c o u n t e r c l o c k w i s e ,
c i r c u l a r p a t h , f i r s t toward t h e s o u t h - s o u t h e a s t and t h e n
toward t h e n o r t h e a s t .
It d i s a p p e a r e d in t h e v i c i n i t y o f
Norton AFB, approximately 10 minutes a f t e r i t was f i r s t
observed.
S t a t e m e n t s from o t h e r c o n t r o l l e r s i n the c e n t e r
confirmed t h a t t h e code 7700 was r e c e i v e d on t h e Boron and
Mt.
Laquna r a d a r systems, b u t n o t on t h e San Fedro system.
The S a f e t y Board a t t e m p t e d t o i d e n t i f y the source of t h e
No e x p l a n a t i o n h a s been
Code 7700 b u t w a s u n s u c c e s s f u l .
found f o r t h e f a i l u r e of t h e San Pedro system t c r e c e i v e t h e
Code 7700.
1.9
Communications
There were no r e p o r t e d d i f f i c u l t i e s w i t h ccmrnunications
between e i t h e r RW706 o r BuNo458 and t h e r e s p e c t i v e ground
f a c i l i t i e s c o n t a c t e d by each.
1.10
Aerodrome and Ground F a c i l i t i e s
Not a p p l i c a b l e .
1.11
F l i g h t Recorders
RW706 w a s equipped w i t h a S u n d s t r a n d E a t a C o n t r o l
f l i q h t d a t a r e c o r d e r , Model FA-542, S e r i a l No.
1810.
The
o u t e r case s u s t a i n e d extreme e x t e r n a l h e a t and f i r e damage,
b u t o n l y minor mechanical damaqe.
The m e t a l f o i l w a s
i n t a c t , b u t d e p o s i t s of soot, molten m e t a l , and o t h e r
r e s i d u e r e q u i r e d e x t e n s i v e c l e a n i n g t o expose t h e r e c o r d e d
parameters.
A l l p a r a m e t e r s were f u n c t i o n i n g ; however, t h e
t r a c e s were f a i n t and d i f f i c u l t t o i d e n t i f y i n c e r t a i n a r e a s
a f t e r t h e c l e a n i n g process.
The t o t a l e l a p s e d t i m e of
r e c o r d i n g was 8 minutes 55 seconds.
Based on a l t i t u d e
i n f o r m a t i o n p r i o r t o d e p a r t u r e from Los Angeles,
the
r e c o r d e r was r e c o r d i n g a l t i t u d e 51 f e e t low. The r e c o r d e d
v a l u e s a t time 8 minutes 54.6 seconds were + 0.749,
0410,
327 knots, and 15,125 f e e t . During t h e f o l l o w i n g 0.6-second
t i m e p e r i o d , t h e v e r t i c a l a c c e l e r a t i o n t r a c e moved t o + 5 - 0 9
a t 8 minutes 55.2 seconds and i n s t a n t a n e o u s l y t o -1.89.
The
l a s t r e c o r d e d parameter v a l u e s p r i o r t o e l e c t r i c a l power
l o s s a t 8 minutes 55.2 seconds were -1.89,
041° 327 k n o t s ,
and 15,150 f e e t .
Rw706
a l s o was equipped w i t h a United Control c o c k p i t
serial number unknown.
The
v o i c e r e c o r d e r , Model V-557,
f i r e damaqe consumed t h e d u s t c o v e r , and a l l t h e r m a l p r o t e c t i v e w a t e r and g l y c o l had been expended. There was no
deformation of t h e s t a i n l e s s s t e e l magazine, h u t o n l y i r o n
o x i d e d u s t w a s found i n t h e t a p e s t o r a g e compartment.
As a
r e s u l t , no d a t a were a v a i l a b l e .
BuNo458 w a s n o t equipped w i t h any f l i g h t r e c o r d e r s and
none were r e q u i r e d .
1.12
Wreckaqe
The main wreckage of t h e two a i r c r a f t was s c a t t e r e d
o v e r a p p r o x i m a t e l y 2 s q u a r e miles. The EC-9 c r a s h e d i n a
canyon w i t h approximately 600 s l o p e s .
Structure
from
F u s e l a g e S t a t i o n (FS) 427 a f t , i n c l u d i n g wings and empennage
was l o c a t e d i n t h i s a r e a .
One p i e c e of F-4E a f t f u s e l a g e
s t r u c t u r e was a l s o found a t the DC-9 c r a s h s i t e . T h i s p i e c e
of t h e F-4E had become e n t a n q l e d i n e l e c t r i c a l w i r i n g which
was i n s t a l l e d between FS318 and FS1099 of t h e DC-9.
The F-4B main wreckage s i t e was l o c a t e d i n a n o t h e r
canyon approximately t h r e e q u a r t e r s of a mile s o u t h e a s t of
t h e DC-9.
The o n l y major s t r u c t u r e n o t i d e n t i f i e d a t t h i s
s i t e i n c l u d e d most o f t h e r i g h t o u t e r wing, t h e c e n t e r l i n e ,
t o p , a f t , f u s e l a g e s t r u c t u r e and t h e empennage.
Wreckage p o r t i o n s of t h e DC-9 forward f u s e l a g e were
removed, and a f u l l - s c a l e three-dimensional mockup of t h i s
s e c t i o n was made.
A s i l h o u e t t e of t h e F-4B w a s t h e n
c o n s t r u c t e d with lumber.
This s i l h o u e t t e was placed i n
v a r i o u s p o s i t i o n s and a t t i t u d e s t o a t t e m p t t o match t h e t w o
d i s t i n c t damage p a t h s through t h e DC-9.
One p a t h was long
and narrow, o r i e n t e d a t an a n g l e o f 300 t o the EC-9 f u s e l a g e
r e f e r e n c e plane, and passed through t h e f u s e l a g e i n t h e a r e a
below t h e main passenger loading door and f i r s t 10 windows.
The o t h e r path was r e c t a n g u l a r and passed through t h e
forward, lower, c o c k p i t area.
When t h e F-4B v e r t i c a l
s t a b i l i z e r was p o s i t i o n e d a t approximately FS110
(the
f u s e l a g e a r e a beneath the windscreen) on t h e l e f t s i d e o f
t h e DC-9 t h e r i g h t wing was i n t h e damage area under the
cabin door and windows.
Both damage p a t h s were on a
descending a n g l e o f approximately 200 through t h e DC-9.
However, both damage swaths were l a r g e r than t h e F-4B
s t r u c t u r e , and t h i s a n g l e could v a r y as much as 100 i n
either d i r e c t i o n .
It is n o t known whether t h e downward
t r a j e c t o r y of t h e two swaths r e s u l t e d p r i m a r i l y from the
r e l a t i v e f l i g h t p a t h s o f the t w o a i r c r a f t or t h e p r o g r e s s i v e
d i s i n t e g r a t i o n o f t h e F-4B s t r u c t u r e a s it passed through
t h e EC-9.
No evidence of i n - f l i g h t f i r e was found on t h e DC-9;
however, t h e F-4B caught f i r e f o l l o w i n g t h e c o l l i s i o n .
There was a s e v e r e around f i r e a t each of t h e main c r a s h
A t o t a l of seven f i r e t r u c k s , two h e l i c o p t e r s ,
one
sites.
a i r t r a f f i c c o n t r o l u n i t , and approximately 72 o f f i c e r s and
men responded t o t h e f i r e alarm.
1.14
Survival ASDeCtS
T h i s was a nonsurvivable a c c i d e n t f o r t h e occupants of
t h e EC-9.
The midair c o l l i s i o n was s u r v i v a b l e f o r t h e occupants
of the F-4B.
The R I O s u c c e s s f u l l y e j e c t e d and he w a s
subsequently rescued uninjured. The p i l o t w a s n o t a b l e t o
eject and the F-4B c o l l i s i o n w i t h t h e ground w a s nonsurvivable.
BuNo458 w a s equipped w i t h a Martin-Baker H 7 r o c k e t
e j e c t i o n s e a t i n each cockpit.
T h i s s e a t was n o t designed
t o be f i r e d through the canopy, and i n c o r p o r a t e d a canopy
i n t e r r u p t e r block
an occurrence.
i n t h e a c t u a t i o n l i n k a g e t o p r e v e n t such
The f r o n t s e a t f a c e c u r t a i n , t h e primary means o f f i r i n g
t h e s e a t , was n o t recovered.
The a l t e r n a t e f i r i n g h a n d l e
had been a c t u a t e d .
D i s t o r t i o n of t h e a c t u a t i o n l i n k a g e
i n d i c a t e d t h a t t h e canopy i n t e r r u p t e r b l o c k
prevented
f u r t h e r movement o f t h e mechanism and s u b s e q u e n t e j e c t i o n of
the pilot.
I n a d d i t i o n t o the canopy u n l o c k system provided i n t h e
systems
are
e j e c t i o n sequence, t w o manually o p e r a t e d
provided.
However, r e g a r d l e s s o f which method i s used t o
unlock t h e canopy, cases have been r e p o r t e d wherein t h e
f r o n t canopy f a i l e d t o j e t t i s o n when t h e a f t canopy was
jettisoned f i r s t .
A s a r e s u l t o f t h e s e o c c u r r e n c e s a change i n t h e canopy
j e t t i s o n mechanism was i n s t i t u t e d t o i n c o r p o r a t e b a l l i s t i c
canopy t h r u s t e r s t o a s s u r e t h a t t h e canopy would s e p a r a t e
from t h e a i r c r a f t .
T h i s m o d i f i c a t i o n had n o t been i n s t a l l e d
i n EuNo458. T h i s change was b e i n g i n c o r p o r a t e d in a l l F-4B
a i r c r a f t on a f l e e t w i d e basis, and m o d i f i c a t i o n of a i r c r a f t
a t MCAS E l Toro was s c h e d u l e d t o b e g i n i n J u l y 1971.
1.15
T e s t s and Research
A r a d a r f l i g h t check o f
t h e San Pedro r a d a r was
conducted on J u n e 8, 1971, u s i n g a n F-4B.
Routine scheduled
maintenance had been performed on t h e system between t h e
t i m e o f t h e a c c i d e n t and t h e f l i g h t check. The R I O had n o t
been f o r m a l l y i n t e r v i e w e d by S a f e t y Board i n v e s t i g a t o r s a t
t h a t time.
Consequently, t h e f l i g h t t r a c k w a s o n l y an
approximation o f t h e presumed t r a c k . The San Fedro system
was c a p a b l e of t r a c k i n g t h e primary t a r g e t of t h e F-4B above
7,500
feet.
S e v e r a l c o n t r o l l e r s commented t h a t t h e y had
never s e e n t h e r a d a r perform so w e l l .
The S a f e t y Board c o o r d i n a t e d w i t h t h e F e d e r a l A v i a t i o n
A d m i n i s t r a t i o n (FAA) and t h e U. S. Marine Corps t o c o n d u c t
a n o t h e r f l i q h t check o f the San Pedro radar on J u n e 16,
1971. The t r a c k of BuNo458 d e s c r i b e d by t h e R I O was
d u p l i c a t e d a s c l o s e l y a s p o s s i b l e on t h r e e r u n s , w i t h some
v a r i a t i o n s i n t h e a l t i t u d e on one run.
Three a d d i t i o n a l
runs
were
conducted i n t h e g e n e r a l area t h e f l i g h t
t r a v e r s e d , b u t w i t h f l i g h t t r a c k and a l t i t u d e v a r i a t i o n s a s
s u q q e s t e d by t h e w i t n e s s group.
The r a d a r s c o p e , channel,
and c o n t r o l s e t t i n g s were t h e same a s a t t h e time of t h e
accident, except t h a t the secondary t a r g e t was o f f s e t s o
t h a t it would n o t i n t e r f e r e with t r a c k i n g t h e F-4B primary
target.
Tracking c o n t i n u i t y was poor and t h e primary t a r g e t
The secondary
was v i s i b l e less t h a n 50 p e r c e n t o f t h e time.
t a r g e t d i d provide a s s i s t a n c e i n following t h e a i r c r a f t
movement d u r i n g v o i d s i n t h e primary t a r g e t coverage.
Photographs o f t h e t e s t runs, a s displayed on a maintenance
monitor, were t a k e n on v i r t u a l l y every sweep of t h e antenna.
These photographs w e r e s t u d i e d by t h e a i r t r a f f i c c o n t r o l
group.
The examination corroborated t h e i n i t i a l r e a c t i o n t o
t h e t r a c k i n g q u a l i t y of the F-4B t a r g e t , b u t it a l s o
demonstrated t h a t t h e primary t a r g e t a l o n e was n o t of
s u f f i c i e n t s t r e n g t h t o a s s u r e n o t i c e by a c o n t r o l l e r who was
unaware of t h e a i r c r a f t presence.
The F-4B i n each test was n o t configured t h e same a s
BuNo458 a t t h e t i m e of t h e accident.
The f i r s t t e s t F-4B
was i n a c l e a n c o n f i g u r a t i o n , and t h e second F-4B t e s t
a i r c r a f t was equipped w i t h two l a r g e wing tanks. A baggage
t a n k was i n s t a l l e d on the f u s e l a g e c e n t e r l i n e of BuNo458.
Consequently, BuNo458 r e p r e s e n t e d a l a r g e r r e f l e c t i v e crosss e c t i o n f o r r a d a r d e t e c t i o n than t h e f i r s t test a i r c r a f t ,
and less r e f l e c t i v e s u r f a c e than t h e second a i r c r a f t . The
v a l i d i t y o f t h e f l i g h t checks a l s o was compromised by such
v a r i a b l e s as meteorological phenomena and d e t e r i o r a t i o n i n
o p e r a t i n g p a r t s of t h e r a d a r o r improved performance due t o
replacement of f a i l e d p a r t s .
A v i s i b i l i t y s t u d y w a s conducted t o determine t h e
p h y s i c a l l i m i t a t i o n s t o v i s i o n from t h e c o c k p i t of each
a i r c r a f t . A f l i g h t ~ a t hf o r each a i r c r a f t was reconstructed.
(See Attachment 1.)
The c o l l i s i o n geometry and c l o s u r e
r a t e s f o r t h e l a s t 40 seconds also was reconstructed.
(See
Attachment 2.)
The f l i g h t p a t h of RW706 w a s based on t h e
f l i g h t r e c o r d e r d a t a , and t h e F-4B f l i g h t p a t h was p r e d i c a t e d
on t h e s t a t e m e n t of t h e RIO. A d u a l l e n s camera was used t o
record a panoramic view from t h e design eye-reference p o i n t
a t each crewmemberas s t a t i o n .
(See Attachments 3 and 4.)
These b i n o c u l a r photographs show t h e p o s i t i o n o f each a i r c r a f t i n t h e f i e l d of v i s i o n o f each crewmemfcer, based on
h i s fixed-eye-reference point.
Naturally, any movement from
t h i s p o s i t i o n would a f f e c t t h e l o c a t i o n of t h e o t h e r
a i r c r a f t i n h i s f i e l d of vision.
I n t h e c o u r s e of t h i s i n v e s t i g a t i o n , t h e McDonnellDouglas C o r p o r a t i o n provided i n f o r m a t i o n c o n c e r n i n g r o l l and
p i t c h r a t e s f o r t h e F-4B a i r c r a f t .
The f o l l o w i n g h a s been
e x t r a c t e d from t h e s u p p l i e d data:
Subject
Full Stick
Throw
What would be t h e maximum r a t e of s t e a d y nosedown p i t c h ?
-10 deg./sec.
Concernina t h e nosedown p i t c h rate, what
would b e t h e time
i n t e r v a l r e q u i r e d from
the f i r s t control input
112
S t i c k Throw
1/4
S t i c k Throw
-4 deg./sec.
-2.5
deg./sec.
to;
(a)
(b)
Achieve i n i t i a l a i r c r a f t movement?
0.10 sec.
Achieve t h e maximum
s t e a d y nosedown
pitch r a t e
7.0 sec.
How many d e g r e e s nosedown would have been
achieved a t t h e p o i n t
t h a t t h e maximum p i t c h
r a t e had been a t t a i n e d
15.0 deg.
0.10 sec.
6.5 sec.
sec.
6.0
sec.
deg.
5.0 deg.
270 f t .
4 26
590 f t .
436
alt. loss
180 f t .
385 f t .
K'IAS 424 430
620 f t .
437
A l t i t u d e l o s t and a i r speed a t 200 nosedown
pitch:
a ) a l t . l o s s 16 f t .
b) KTAS 420
9.0
0.10
A l t i t u d e loss and a i r s p e e d 9 200
nosedown f l i q h t p a t h angle:
a)
b)
I n a d d i t i o n t a the above, t h e d a t a i n d i c a t e d t h a t a
bank of 300 c o u l d b e a c h i e v e d i n a s l i t t l e time a s 0.75
second.
I f r o l l - a n d - p i t c h c o n t r o l i n p u t s are coupled d u r i n g
t h e maneuver, t h e t i m e t o a c h i e v e a g i v e n b a n k / p i t c h
a t t i t u d e is less t h a n t h e t i n e r e q u i r e d i f t h e a t t i t u d e is
achieved as t h e r e s u l t of two s e p a r a t e maneuvers.
In this
i n s t a n c e , t h e d a t a i n d i c a t e t h a t a 200 nosedown,
300 l e f t
bank a t t i t u d e c o u l d be achieved i n less t h a n 3 seconds.
1.16
Other
The S t a f f V i c e P r e s i d e n t , F l i g h t O p e r a t i o n s f o r A i r
s t a t e d t h a t a t t e m p t s were made t o f o s t e r
crew
v i g i l a n c e and scanning by minimizing crew d u t i e s i n t h e
c o c k p i t , u s e of c h e c k l i s t procedures, encouraging u s e o f t h e
a u t o p i l o t a s much as p o s s i b l e , and through emphasis i n t h e i r
t r a i n i n g program.
However, the v a r i o u s manuals and t r a i n i n g
programs d i d n o t s p e c i f i c a l l y c o n t a i n any statement r e l a t i n g
t o l o o k o u t d o c t r i n e or scanning t e c h n i q u e s , nor d i d t h e
company have any p l a n t o implement such a program.
West,
The p i l o t of BuNo458 r e c e i v e d t r a i n i n g i n l o o k o u t
d o c t r i n e and scanning t e c h n i q u e s i n f l i g h t school.
After
assignment t o t h e squadron, t h e p i l o t and R I O r e c e i v e d
a d d i t i o n a l t r a i n i n g on scan t e c h n i q u e s w i t h emphasis on
t a c t i c a l i n t e r c e p t and p u r s u i t . Each p i l o t and R I O r e c e i v e s
formal upqradinq and r e f r e s h e r v i s i o n t r a i n i n g a t l e a s t once
A d d i t i o n a l l y , t h e crews r o u t i n e l y i n c l u d e
e v e r y 3 years.
reminders in lookout d o c t r i n e d u r i n g b r i e f i n g f o r each
multiple a i r c r a f t f l i g h t .
2.
ANALYSIS AND CONCLUSIONS
2.1
Analvsis
(a)
ATC and Radar F a c t o r s
The primary f u n c t i o n of r a d a r i s t o p r o v i d e t h e
controller with a v i s u a l p r e s e n t a t i o n which w i l l assist him
in the c o n t r o l and s e p a r a t i o n o f known t r a f f i c . It also
-
provides t h e c o n t r o l l e r with another l i m i t e d c a p a b i l i t y
t h a t of p r o v i d i n g s e p a r a t i o n o f i d e n t i f i e d from u n i d e n t i f i e d
t r a f f i c t h r o u g h t h e medium o f t h e t r a f f i c a d v i s o r y when
workload permits.
I n some cases, due t o t h e t e c h n i c a l
l i m i t a t i o n s of t h e r a d a r equipment, adequate s e p a r a t i o n h a s
n o t been achieved.
Because of t h e mix of known and unknown
t r a f f i c it i s n o t o n l y incumbent upon aircrews t o m a i n t a i n a
h i g h d e g r e e of v i g i l a n c e t o "see and avoid", h u t a l s o upon
t h e c o n t r o l l e r s i n monitoring t h e r a d a r d i s p l a y .
In t h i s
a c c i d e n t three independent r a d a r systems f a i l e d t o d e t e c t
t h e primary t a r g e t of BuNo458 and as a r e s u l t n o warning w a s
g i v e n t o t h e crew of Kt4706 r e g a r d i n g t h e d i r e c t i o n and
d i s t a n c e o f t h e hazard.
I f t h e crew of RK706 had been
provided w i t h t h i s i n f o r m a t i o n t h e i r c h a n c e s of s e e i n g and
a v o i d i n q t h e o t h e r a i r c r a f t would have been enhanced.
One
s o l u t i o n t o t h e l i m i t a t i o n s of r a d a r
would
be
the
establishment
of
some minimum s t a n d a r d o f r e f l e c t i v e
c a p a b i l i t y f o r a l l a i r c r a f t and t h e i n c o r p o r a t i o n of some
form o f s i g n a l enhancement equipment a b o a r d a l l a i r c r a f t , as
n e c e s s a r y t o meet t h e s t a n d a r d , a s p r e v i o u s l y recommended by
(See Report Number: NTSE-AAS-70-2,
pages 119t h e Board.
128.)
The r a d a r c o v e r a g e c h a r t ( c l a s s i f i e d f o r m i l i t a r y
s e c u r i t y ) f o r t h e San Pedro system i n d i c a t e s t h a t t h e
c o l l i s i o n o c c u r r e d a t an a l t i t u d e which i s w i t h i n t h e b a s i c
r a d a r l i n e o f s i g h t coverage.
The l i m i t a t i o n s t o r a d a r
a d v i s o r y s e r v i c e w i t h i n t h a t c o v e r a g e area i n c l u d e more t h a n
t h e c o n t r o l l e r workload. O t h e r f a c t o r s a f f e c t i n g d e t e c t i o n
of primary t a r g e t s i n c l u d e :
(1)
(2)
(3)
(4)
Radar c r o s s - s e c t i o n p r e s e n t e d by t h e d e s i g n
and c o n f i g u r a t i o n o f t h e a i r c r a f t
Weather c o n d i t i o n s s u c h a s p r e c i p i t a t i o n
and t e m p e r a t u r e i n v e r s i o n s
Ground c l u t t e r
Blind s p o t s
I n t h i s i n s t a n c e , d e t e c t i o n of EuN0458 was hampered by
t h e a i r c r a f t radar
cross-section
and
a
temperature
inversion.
Althouqh s i m u l a t i o n s of t h e f l i g h t c a t h i n d i c a t e
t h a t t h e primary t a r g e t was i n t e r m i t t e n t l y d e t e c t a b l e , t h e
low p r o b a b i l i t y of s u c h d e t e c t i o n i s d r a m a t i z e d i n t h e
f o l l o w i n g computation:
The t o t a l e l a p s e d time a t a r g e t would have been
d e t e c t a b l e was 120 seconds, e q u a l t o 10 sweeps o f t h e
antenna.
A t a p p r o x i m a t e l y 420 k n o t s
( 7 miles p e r
minute!.. - t h e a i r c r a f t would t r a v e l 1.4 miles d u r i n q
e a c h sweep. The t a r g e t would a c t u a l l y move a t o t a l of
2.5 i n c h e s , or 0.25-inch/sweep,
a c r o s s t h e 21-inch
display.
The s m a l l t i m e e l e m e n t i n v o l v e d and s h o r t
d i s t a n c e moved, i n combination w i t h t h e p r o b a b i l i t y o f
less t h a n 50
percent
primary
target
tracking
c o n t i n u i t y , i n d i c a t e t h a t it would have been e x t r e m e l y
d i f f i c u l t f o r t h e c o n t r o l l e r s t o d i f f e r e n t i a t e between
normal c l u t t e r and a n a i r c r a f t r e t u r n , i f any t a r g e t
was d i s p l a y e d a t a l l .
The volume of t r a f f i c and c o n t r o l l e r workload a s s o c i a t e d
w i t h t h e R-18 sector were s u f f i c i e n t l y l i g h t t o permit r a d a r
t r a f f i c a d v i s o r i e s i f requested.
Advisories on p o s s i b l e
c o n f l i c t i n g t r a f f i c were being given t o o t h e r c o n t r o l l e d
a i r c r a f t during t h e time period surrounding the c o l l i s i o n .
A l l f o u r c o n t r o l l e r s a s s o c i a t e d with t h e a c t i v i t y a t the
p o s i t i o n s t a t e d t h a t no primary t a r g e t s were observed i n t h e
v i c i n i t y of RW706.
Consequently, t h e Board concludes t h a t
no r e a d i l y d i s c e r n i b l e t a r g e t from BuNo458 was displayed.
If a request f o r radar advisories
had
alerted
the
c o n t r o l l e r s t o t h e presence of an a i r c r a f t i n t h a t a r e a , any
i n t e r m i t t e n t o r q u e s t i o n a b l e t a r g e t s i g h t e d could have been
t e n t a t i v e l y i d e n t i f i e d a s EuNo458.
The R-18 c o n t r o l l e r
could have advised RW706 of t h e c o n f l i c t i n g t r a f f i c under
t h e s e circumstances.
(b)
ReDOrtS
of A i r c r a f t Acrobatics
During t h e i n v e s t i g a t i o n c o n s i d e r a b l e p u b l i c a t t e n t i o n
focused on w i t n e s s r e p o r t s of a n a i r c r a f t performing
The R I O
a c r o b a t i c s in t h e v i c i n i t y of t h e c o l l i s i o n .
t e s t i f i e d t h a t o n l y one a i l e r o n r o l l was performed by t h e
p i l o t of BuNo458, as he l e v e l e d o f f a t 15,500 f e e t .
An
a n a l y s i s o f the f l i g h t from NAAS F a l l o n i n d i c a t e s t h a t t h e r e
was i n s u f f i c i e n t t i m e a v a i l a b l e f o r any repeated maneuvers
t o have been performed.
T h e w i t n e s s e s might have been
observing a n o t h e r a i r c r a f t , o r t h e y were a c t u a l l y viewing
t h e q y r a t i o n s of BuNoU58 follOwinq t h e c o l l i s i c n .
Whereas
no s p e c i f i c F e d e r a l Aviation Regulation p r o h i b i t e d t h e
a i l e r o n r o l l , t h e a b i l i t y o f t h e crew t o s e e o t h e r a i r c r a f t
during t h e maneuver w a s unquestionably minimal due t o the
r a p i d l y changing a t t i t u d e and t h e a c c e l e r a t i o n
forces
imposed.
The Board concludes t h a t the a i l e r o n r o l l had no
o t h e r s i g n i f i c a n c e t o the a c c i d e n t , s i n c e t h e t w o a i r c r a f t
were s e p a r a t e d by approximately 13 miles a t t h e t i m e .
However, it w a s imprudent o f t h e p i l o t t o perform such a
maneuver i n o t h e r t h a n an a c r o b a t i c area.
was
(c) g ~ e r a t i o n a lF a c t o r s
This a c c i d e n t i s a n o t h e r example of a heterogeneous mix
of VFR and I F R t r a f f i c , with each a i r c r a f t complying with
applicable regulations, r e s u l t i n g i n a midair c o l l i s i o n .
S e v e r a l f a c t o r s i n t h e o p e r a t i o n o f t h e two a i r c r a f t
combined t o provide t h e c o n d i t i o n s s u i t a b l e f o r a midair
collision.
1.
O p e r a t i o n of BuNo458
Mechanical d i f f i c u l t i e s w i t h BuNo458, and t h e r e s u l t i n g
o p e r a t i o n a l d e c i s i o n s , placed t h e a i r c r a f t a t low a l t i t u d e
and h i q h a i r s p e e d , i n s t e a d of i n t h e APC, a s would normally
be e x p e c t e d on c r o s s - c o u n t r y f l i g h t s .
The t r a n s p o n d e r had
f a i l e d on t h e p r e v i o u s day, making e n t r y i n t o t h e p o s i t i v e
c o n t r o l a i r s p a c e dependent on t h e d i s c r e t i o n of t h e a i r
t r a f f i c control facility.
When t h e oxygen system a l s o
became d e f e c t i v e , w i t h no o p p o r t u n i t y t o r e p a i r e i t h e r
system,
t h e d e c i s i o n t o proceed t o MCAS E l Toro a t
r e l a t i v e l y low a l t i t u d e was t h e o b v i o u s s o l u t i o n t o b o t h
problems.
The t r a n s p o n d e r was n o t r e q u i r e d , and c o c k p i t
p r e s s u r i z a t i o n n e q a t e d t h e p h y s i c a l need f o r s u p p l e m e n t a l
oxygen,
even i f t h e l e a k d e p l e t e d t h e e n t i r e supply.
The
oxyqen l e a k d i d i n c r e a s e , and most of t h e f l i q h t t o MAAS
F a l l o n w a s flown w i t h o u t s u p p l e m e n t a l oxygen.
A t this
p o i n t , t h e p i l o t was i n s t r u c t e d by h i g h e r a u t h o r i t y t o
complete
the
f l i g h t w i t h t h e d e f e c t i v e systems.
An
a d d i t i o n a l s i g n i f i c a n t f a c t o r i n t h e o p e r a t i o n of BuNo458
was t h e h i g h - c r u i s i n g a i r s p e e d , which i s t y p i c a l o f modern
j e t a i r c r a f t . The h i g h a i r s p e e d w a s used t o a v o i d h i q h
s p e c i f i c f u e l consumption and t h e less s t a b l e f l i g h t regime
encountered a t s l o w e r a i r s p e e d s . Consequently, t h e probab i l i t y of v i s u a l d e t e c t i o n w a s minimized by t h e speed, s i z e ,
and unexpected p r e s e n c e of BuNo458.
I n a d d i t i o n t o t h e s e o p e r a t i o n a l c o n s t r a i n t s imposed on
t h e p i l o t of BuNo458, c o n s i d e r a t i o n of t r a f f i c and weather
c o n d i t i o n s was a l s o evidenced i n t h e p l a n n i n g and conduct of
the fliqht.
The p i l o t of BuNo458 was s u f f i c i e n t l y aware of t h e heavy
volume of t r a f f i c i n t h e Los Angeles area t o a l t e r h i s
He
f l i q h t t o t h e e a s t i n o r d e r t o a v o i d any c o n f l i c t .
f u r t h e r demonstrated concern f o r a d e q u a t e v i q i l a n c e by
c l i m b i n g t o 15,500 f e e t because of t h e
deteriorating
visibility.
However, t h e a d v a n t a g e which would have a c c r u e d
from t h e d e v i a t i o n around Los Angeles was l a r g e l y o f f s e t by
t h e s u b s e q u e n t climb t o h i g h e r a l t i t u d e .
This placed
EuNo458 i n t h e a i r s p a c e segment n o r m a l l y used by eastbound
t r a f f i c climbinq t o t h e h i g h - a l t i t u d e r o u t e s t r u c t u r e .
Two o t h e r d e c i s i o n s by t h e p i l o t of BuNo458 a l s o had a
s i g n i f i c a n t e f f e c t on t h e c o l l i s i o n .
F i r s t he d i d n o t
attempt t o request radar t r a f f i c advisories.
T h i s would
have
alerted
the
appropriate
controller
that
a
nontransponder t a r g e t was i n t h e a r e a and undoubtedly would
to
establish
radar
have
resulted
in
an
attempt
identification.
Even i f r a d a r contact had
not
been
accomplished a t t h a t time, t h e g e n e r a l l o c a t i o n would have
been e s t a b l i s h e d , and t r a f f i c a d v i s o r i e s could have been
i s s u e d accordingly.
I n s p i t e o f t h e f a c t t h a t crews
sometimes do n o t s i g h t t h e t r a f f i c even
thouqh
the
a d v i s o r i e s a r e i s s u e d i n s p e c i f i c terms (clock code and
d i s t a n c e ) t h e i s s u a n c e of a g e n e r a l warning (geographic
l o c a t i o n and d i r e c t i o n o f f l i g h t ) would have served t o
narrow t h e f i e l d of search,
thereby
increasing
the
p r o b a b i l i t y of d e t e c t i o n .
Secondly, he requested t h e R I O t o conduct a r a d a r
mapping e x e r c i s e a t a time when he was t r a v e r s i n g an a r e a of
dense t r a f f i c .
Although it may be arqued t h a t o u t s i d e
v i s i b i l i t y from t h e rear c o c k p i t is r e l a t i v e l y poor, a l l
p o s s i b l e a s s i s t a n c e i n maintaining a lookout should have
been used.
I f any r a d a r e x e r c i s e were t o have been
conducted, it should have been i n t h e s e a r c h mode.
Even i n
t h e degraded c o n d i t i o n of the radax, t h i s would have been
preferable.
2.
Ooeration of RW706
An a n a l y s i s of t h e f i n a l 0.6 second of
f l i g h t recorder
o p e r a t i o n shows t h a t a t 8 minutes 54.6 seconds, t h e v e r t i c a l
a c c e l e r a t i o n t r a n s d u c e r sensed a p o s i t i v e g f o r c e , movinq
from +0.74g and culminating i n a +5.08g r e a d i n g a t 8 minutes
55.2 seconds.
A t t h e i n s t a n t t h e s t y l u s recorded t h i s ,
it
moved i n s t a n t a n e o u s l y t o a -1.8q reading.
The r e t u r n to,
and o v e r t r a v e l beyond, a + l g (normal) p o s i t i o n (-1.8q), w i t h
no measurable e l a p s e d time,
strongly
suggested
rapid
response o r normalizing o f t h e s p r i n g - r e s t r a i n e d seismic
mass i n t h e electromechanical
transducer
after
high
e x c i t a t i o n i n the p o s i t i v e d i r e c t i o n . These g r e c o r d i n g s
were made p o s s i b l e by t h e r e c o r d i n g r a t e o f 10 p e r second
f o r t h i s parameter, whereas t h e o t h e r t h r e e parameter r a t e s
a r e one p e r second.
The S a f e t y Board b e l i e v e s t h a t t h e s e e x c u r s i o n s on t h e
a c c e l e r a t i o n t r a c e r e s u l t e d from shock l o a d i n g a t impact and
n o t from any attempted e v a s i v e maneuver by RW706.
S i n c e t h e crew of RW706 t o o k n o e v a s i v e a c t i o n p r i o r t o
t h e c o l l i s i o n , t h i s i n d i c a t e s t h a t e i t h e r t h e y d i d n o t see
BuNo458 o r saw i t too l a t e t o t a k e a p p r o p r i a t e a c t i o n .
There a r e s e v e r a l f a c t o r s which i n d i v i d u a l l y o r c o l l e c t i v e l y
c o u l d have reduced t h e a b i l i t y o f t h e DC-9 crew t o see and
avoid t h e I?-4B.
The crew probably engaged t h e a u t o p i l o t t o
m a i n t a i n c l i m b s c h e d u l e and, under r a d a r c o n t r o l ,
probably
expected t r a f f i c a d v i s o r i e s of converqing t a r g e t s from t h e
controller.
F u r t h e r r e d u c t i o n i n o u t s i d e v i g i l a n c e miqht
have
resulted
from such normal c o c k p i t f u n c t i o n s as
d e t e r m i n i n g or changing v a r i o u s r a d i o f r e q u e n c i e s , a d j u s t i n g
s e t t i n g s o r c o n t r o l s of t h e f l i q h t d i r e c t o r or t h r u s t
levers.
However,
t h e p r o b a b l e r e a s o n s why t h e RW706 crew
d i d n o t see BuNo458 were:
(1) b o t h a i r c r a f t had a n e a r l y
constant r e l a t i v e hearing t o each other;
(2) t h e h i g h
c l o s u r e s p e e d s ; (3) t h e l a c k of c o n s p i c u i t y of EuMo458; and
(4)
t h e l a c k of r e c u r r e n t t r a i n i n g i n e f f i c i e n t l o o k o u t
d o c t r i n e and s c a n n i n g t e c h n i q u e s .
(dl
Human F a c t o r s i n T a r g e t D e t e c t i o n and Assessment
The Board's c o c k p i t v i s i b i l i t y s t u d y (Attachments 3 and
l e a s t 40 seconds p r i o r t o impact,
EuNo458 was less t h a n 450 t o t h e l e f t of t h e DC-9 c a p t a i n ' s
and f i r s t o f f i c e r ' s normal s i g h t l i n e .
Approximately 35
seconds p r i o r t o c o l l i s i o n , RW706 completed a l e f t t u r n and
was t h e n c l i m b i n g on a c o n s t a n t heading.
Although t h e
t a r g e t s i z e of EuNo458 was s m a l l a t t h i s time (0.017-inch),
t h e smoke t r a i l from e n g i n e e x h a u s t would have at. l e a s t
tripled
the effective target size.
The v i s u a l a n g l e
subtended by s u c h a t a r g e t would be approximately 10.8
minutes of a r c .
The e m p i r i c a l l y d e r i v e d t h r e s h o l d f o r
A t approximately
d e t e c t i o n i s nominally 4 minutes of a r c .
15 seconds b e f o r e t h e c o l l i s i o n , j u s t p r i o r t o t h e o n s e t of
t h e fi~blosscminq e f f e c t " which o c c u r r e d a s t h e i n t r u d e r
t a r g e t s i z e i n c r e a s e d d r a m a t i c a l l y , t h e size o f BuNo458 and
a smoke t r a i l twice i t s l e n g t h would have grown
to
approximately 0.117-inch.
I n t h e n e x t 10 seconds, t h e
t a r q e t s i z e would t r i p l e , i n t h e l a s t 5 seconds it would
expand t o f i l l t h e e n t i r e v i s u a l f i e l d .
These f i g u r e s are
p r e d i c a t e d on t h e c o n s t a n t f o r e s h o r t e n e d l e n q t h of BuNo458
which would r e s u l t from t h e r e l a t i v e p o s i t i o n s of t h e two
4) i n d i c a t e s t h a t a t
a i r c r a f t , and no a t t e m p t w a s made t o a d j u s t f o r the
size d u r i n g the e v a s i v e a c t i o n t a k e n by EuNo458.
The
target
c o c k p i t v i s i b i l i t y study (Attachments 3 and 4) a l s o
indicates that RW706 would have been approximately 390 t o
t h e r i g h t of the normal s i g h t l i n e of t h e p i l o t of BuNo458
and approximately 370 f o r t h e R I O , f o r t h e l a s t 40 seconds
prior t o collision.
The t a r g e t s i z e o f RW706, allowing f o r
t h e f o r e s h o r t e n i n g due t o a n g u l a r displacement, 35 seconds
p r i o r t o impact was approximately 0.037-inch.
A t t h i s point
the t a r g e t would subtend approximately 7 minutes of a r c ,
which is w e l l w i t h i n t h e d e t e c t a b l e t h r e s h o l d mentioned
earlier.
N o a d d i t i o n t o t a r g e t s i z e was made f o r engine
exhaust because one engine was modified, which reduced t h e
v i s i b l e smoke emission.
T h i s would have presented less than
optimum d e n s i t y f o r d e t e c t i o n .
During t h e f i n a l 15-second
p e r i o d p r i o r t o c o l l i s i o n , t h e t a r q e t s i z e of
RW706
blossomed r a p i d l y , t r i p l i n g i n s i z e between 15 seconds and 5
seconds and t h e n expanding t o f i l l t h e e n t i r e v i s u a l f i e l d
i n t h e f i n a l 5 seconds.
Although t h e F-4B and
DC-9
target
images
were
t h e o r e t i c a l l y of s u f f i c i e n t s i z e t o permit d e t e c t i o n a t 35
seconds p r i o r t o c o l l i s i o n , a number of f a c t o r s could have
c o n t r i b u t e d i n t h i s case t o reduce t h e l i k e l i h o o d of
detection a t t h a t t i m e .
I n t h e a n a l y s i s of any midair
collision,
laboratory
data
on
human
response
and
c a p a b i l i t i e s 9/ must be a d j u s t e d t o real-world conditions.
The e x t e n t t o which these d a t a v a r y depends on t h e e f f e c t of
many
factors;
i.e.,
windshield
refractance,
surface
irregularities and c l e a n l i n e s s , s i z e and
location
of
windshield frames, t h e background a g a i n s t which a t a r g e t i s
viewed, atmospheric l i g h t s c a t t e r , and viewer t r a i n i n g ,
a b i l i t y , and preoccupation.
A l l may be involved t o varying
degrees a t t h e t i m e a t a r g e t i s w i t h i n a p e r c e p t i b l e
threshold.
The e x t e n t t o which t h e s e f a c t o r s a f f e c t e d
d e t e c t i o n of RW706 o r Bum458
cannot
be
determined
precisely.
However,
the
various
studies
comparing
l a b o r a t o r y d a t a t o real-world
s i t u a t i o n s show dramatic
r e d u c t i o n i n t h e p r o b a b i l i t y of v i s u a l d e t e c t i o n due t o t h e
f a c t o r s l i s t e d above.
A n o n s t r u c t u r e d o r i l l - d e f i n e d homogeneous background
p r e s e n t s a l e s s - t h a n - d e s i r a b l e f i e l d when t h e s e a r c h f o r a
t a r q e t is conducted.
The l a c k of d e f i n e d
background
texture,
coupled with a c o n s t a n t background hue,
can
s e v e r e l y l i m i t n o t o n l y t h e d e t e c t a b i l i t y of a t a r g e t b u t
a l s o t h e a b i l i t y t o p e r c e i v e t a r g e t motion, once t h e t a r g e t
is detected.
While t h e e f f e c t s of atmospheric
light
s c a t t e r , and t h e r e p o r t e d h a z e l a y e r a t 9,000 f e e t c a n n o t b e
q u a n t i t a t i v e l y determined i n t h i s a c c i d e n t , it i s r e a s o n a b l e
to
surmise
that
RW706
p r e s e n t e d less t h a n optimum
c o n s p i c u i t y when viewed a q a i n s t t h e haze l a y e r .
Moreover,
its
motion r e l a t i v e t o the background haze would b e
d i f f i c u l t t o detect.
Had e i t h e r a i r c r a f t d i s p l a y e d h i g h
i n t e n s i t y s t r o b e l i g h t s , t h e i n c r e a s e d c o n s p i c u i t y probably
would have enhanced e a r l y d e t e c t i o n of each a i r c r a f t .
Another f a c t o r which can a f f e c t t h e d e t e c t a b i l i t y of
a i r b o r n e t a r g e t s i s t h e myopic n a t u r e of the human e y e when
an a i r - t o - a i r s e a r c h i s b e i n g conducted.
The c o n d i t i o n
results
from
the
t e n d e n c y of t h e eye t o f o c u s a t
approximately 20 f e e t d u r i n g a v i s u a l s e a r c h i n t o an
e s s e n t i a l l y empty v i s u a l f i e l d .
Although t h i s c o n d i t i o n i s
more p r e v a l e n t a t extremely h i g h a l t i t u d e s where t h e h o r i z o n
becomes i l l - d e f i n e d and h i g h ambient l i g h t i n q becomes a
f a c t o r , it i s a l s o p o s s i b l e t h a t a myopic c o n d i t i o n c o u l d
e x i s t a t markedly lower a l t i t u d e s when a p i l o t i s s e a r c h i n g
a q a i n s t an i l l - d e f i n e d homogeneous f i e l d .
The p o s s i b i l i t y
t h e r e f o r e e x i s t s t h a t t h e crews of RW706 and BuNo458 c o u l d
have been s u b j e c t t o some d e g r e e o f myopic v i s i o n w i t h a
r e s u l t a n t r e d u c t i o n i n t h e i r a b i l i t y t o d e t e c t a small
tarqet.
F i n a l l y , t h e e f f e c t i v e n e s s o f crew s c a n n i n g is dependent
t r a i n i n g and t h e time s h a r i n g of a c t i v i t i e s i n s i d e and
o u t s i d e of t h e c o c k p i t .
Based on a f i x e d - e y e r e f e r e n c e
point,
n e i t h e r t a r g e t was masked by i n t e r v e n i n g c o c k p i t
s t r u c t u r e f o r any s i g n i f i c a n t p e r i o d o f t i m e ; however, each
t a r g e t was i n t h e p e r i p h e r a l v i s u a l f i e l d 101 of a l l
crewmembers. The l a c k of r e l a t i v e motion of e i t h e r t a r g e t
i n t h e p e r i p h e r a l v i s i o n of any crewmember could have made
e a r l y d e t e c t i o n of t h e o t h e r a i r c r a f t h i g h l y u n l i k e l y .
S i m i l a r l y , t h e s m a l l s i z e and l a c k of r e l a t i v e movement of
e i t h e r t a r g e t , even though d e t e c t e d a t 35 seconds p r i o r t o
collision,
would
undoubtedly
have p r e c l u d e d a c c u r a t e
a s s e s s m e n t of t h e v e r t i c a l and h o r i z o n t a l s e p a r a t i o n o r r a t e
and I?-4
of change of t a r g e t s i z e .
Thus even i f t h e EC-9
crews d e t e c t e d t h e o t h e r a i r c r a f t , t h e c u e s f o r a c c u r a t e
assessment of t h e c o l l i s i o n geometry c o u l d have
been
m a r g i n a l l y adequate.
on
I t may be p o s t u l a t e d t h a t a s t h e closure d i s t a n c e
d e c r e a s e d from 20 t o 10 s e c o n d s p r i o r t o t h e c o l l i s i o n the
target
would become b e t t e r defined and Rft706.s climb
a t t i t u d e could be more a c c u r a t e l y discerned by the p i l o t of
BuN0458.
Thus a s i g h t i n g d u r i n g t h e p e r i o d between 20 and
10 seconds p r i o r t o c o l l i s i o n might
not
have
been
i n t e r p r e t e d a s an imminent c o l l i s i o n t h r e a t because of t h e
sn-.allness of t h e t a r g e t s i z e .
However,
target
size
notwithstanding, t h e f i x e d b e a r i n g of RW706 and i t s l o c a t i o n
n e a r t h e horizon would have suggested t h a t a c o l l i s i o n
t h r e a t e x i s t e d and t h a t he should maneuver t o a s s u r e a
comfortable separation.
Moreover, t h e F-4B p i l o t ' s m i l i t a r y
f l y i n g experience, i n c l u d i n g t a c t i c a l i n t e r c e p t t r a i n i n g
should have i n c r e a s e d t h e l i k e l i h o o d of t h e i n i t i a t i o n of a
r i g h t t u r n or other maneuver which would have increased t h e
miss-distance.
The l a c k of any such maneuver i n d i c a t e s t h a t
he d i d n o t s i g h t t h e DC-9 i n s u f f i c i e n t t i m e t o have
executed an a p p r o p r i a t e maneuver t o avoid t h e c o l l i s i o n .
I n l i g h t of t h e above d i s c u s s i o n of t h e l i k e l i h o o d of
e a r l y d e t e c t i o n , t h e S a f e t y Board concludes t h a t although
d e t e c t i o n of RW706 by t h e p i l o t of EuNo458 might have
occurred as much a s 35 seconds p r i o r t o c o l l i s i o n , it i s
more l i k e l y t h a t it occurred a t some t i m e markedly less than
20 seconds p r i o r t o t h e c o l l i s i o n .
The p o s s i b i l i t y of a n e a r l y d e t e c t i o n of BuNo458 by t h e
However, with BuKo458 l o c a t e d
n e a r t h e horizon and on a c o n s t a n t or n e a r l y c o n s t a n t
bearing, e a r l y d e t e c t i o n probably would have prompted t h e
crew of RW706 t o monitor t h e p r o g r e s s of BuNo458 t h e r e a f t e r
and s e r i o u s l y t o c o n s i d e r a l t e r i n g t h e i r c l i m b schedule o r
headinq
to
ensure s a f e p a s s i n g separation.
Assuming
continued assessment by t h e RW706 crew, a s t h e range
decreased, t h e l i k e l i h o o d o f t h e i r making a precautionary
a l t e r a t i o n i n f l i q h t p a t h would seem t o i n c r e a s e . Therefore,
in t h e absence of any such d e v i a t i o n i n f l i q h t p a t h , t h e
S a f e t y Board concludes t h a t it i s most l i k e l y t h a t t h e crew
of EM706 never saw BuNo458, or saw it moments p r i o r t o t h e
c o l l i s i o n and had no t i m e t o i n i t i a t e a n e v a s i v e maneuver.
crew of RW706 w a s considered.
I n o r d e r t o determine a l i k e l y t i m e f o r d e t e c t i o n o f
RW706 by t h e p i l o t of BuNo458, it was necessary t o c o n s i d e r
t h e R I O ' s warning c o i n c i d e n t w i t h t h e r o l l i n g maneuver a s a
s t a r t i n q p o i n t , t o g e t h e r with a i r c r a f t response times and
l a b o r a t o r y d a t a s u q g e s t i v e o f p i l o t response t i m e s i n
c o l l i s i o n s i t u a t i o n s . The d a t a suggest t h a t it would t a k e
0.24
second t o accommodate t o f o v e a l v i s i o n , cnce a t a r g e t
was detected.
Neural p r o c e s s e s would t a k e an a d d i t i o n a l 0.3
second.
The d a t a f u r t h e r s u g g e s t a s much as 3 seconds c o u l d
have e l a p s e d d u r i n g r e c o g n i t i o n and a s s e s s m e n t o f t h e
v a r i o u s c u e s and d e t e r m i n a t i o n t h a t a p o t e n t i a l t h r e a t
e x i s t e d . Approximately 2 seconds c o u l d have t h e n e l a p s e d
w h i l e d e c i d i n g whether a n e v a s i v e maneuver w a s n e c e s s a r y and
i f so, t h e t y p e o f maneuver t o i n i t i a t e .
Another 0.5 second
c o u l d have e l a p s e d f o r human motor response.
Aircraft
performance d a t a i n d i c a t e a p p r o x i m a t e l y 3 s e c o n d s c o u l d have
been r e q u i r e d f o r a i r c r a f t r e s p o n s e , depending e n t h e r a t e
and t y p e of c o n t r o l i n p u t .
Eased on t h e R I O e s t e s t i m o n y and
a n a l y s i s of o t h e r e v e n t s , t h e p i l o t ' s p a r t i c i p a t i o n i n t h e
r a d a r mapping e x e r c i s e was completed approximately
20
seconds p r i o r t o t h e c o l l i s i o n .
However, t h i s remaining 20
seconds was most l i k e l y n o t e n t i r e l y s p e n t i n c o n s t a n t
v i s u a l s e a r c h o f surrounding airspace.
Such i n t r a c o c k p i t
d u t i e s a s monitoring t h e a t t i t u d e i n d i c a t o r t o maintain
fliqhtpath
a t t i t u d e , a i r s p e e d , and s t a t u s o f a i r c r a f t
subsvstems would have o c c u c i e d some f i n i t e amount of t h i s
time.
~ h u s , t h e time a v a i l a b l e f o r d e t e c t i n g any o u t s i d e
t a r g e t c o u l d have been s i g n i f i c a n t l y less t h a n 20 seconds.
I t i s p o s t u l a t e d t h a t 10 s e c o n d s c o u l d have been s p e n t
performing a noncontinuous v i s u a l s e a r c h o f t h e s u r r o u n d i n g
a i r s p a c e , w h i l e t h e remaining 10 s e c o n d s were s h a r e d w i t h
scanninq c o c k p i t displays.
Because t h e DC-9 t a r g e t w a s v e r y
s m a l l , s t a t i o n a r y , and l o c a t e d i n h i s p e r i p h e r a l v i s i o n ,
it
is most l i k e l y t h a t t h e p i l o t d i d n o t see t h e DC-9 u n t i l
j u s t moments b e f o r e
the
collision.
The
completely
unexpected
a p p e a r a n c e o f t h e DC-9,
t o g e t h e r with its
d r a m a t i c growth i n s i z e d u r i n g t h e 10 s e c o n d s p r i o r t o
collision
r e n d e r e d p r o p e r a s s e s s m e n t of t h e s i t u a t i o n
e x t r e m e l y d i f f i c u l t i f n o t impossible.
The S a f e t y Board
c o n c l u d e s t h e r e f o r e , t h a t it is l i k e l y t h a t t h e p i l o t of
EuNo458 d e t e c t e d Kg706 less t h a n 10 s e c o n d s b e f o r e t h e
c o l l i s i o n and t h a t the e v a s i v e maneuver was i n i t i a t e d
approximately 2 t o 4 seconds b e f o r e c o l l i s i o n .
Within t h e
f i n a l remaining 2 t o 4 s e c o n d s a l e f t r o l l was made as a n
a t t e m p t t o a v o i d a c o l l i s i o n . A more a p p r o p r i a t e maneuver
c o n s i s t e n t w i t h p r e v i o u s t r a i n i n g would have been a r o l l t o
t h e r i g h t t o i n c r e a s e miss-distance.
However, t h e Board
c a n n o t d e t e r m i n e w i t h c e r t a i n t y t h a t even t h i s t y p e of
maneuver would have a s s u r e d s a f e p a s s a g e o f t h e F-4.
The Board f u r t h e r c o n c l u d e s t h a t t h e v i s u a l cues f o r
a c c u r a t e a s s e s s m e n t of t h e c o l l i s i o n geometry by t h e p i l o t
o f BuNo458 probably were i n a d e q u a t e .
Then, when t a r g e t
r a n q e had been reduced s u f f i c i e n t l y t o a f f o r d improved
v i s u a l c u e s , t h e time remaining w a s s o b r i e f as t o make
unduly d i f f i c u l t the accurate assessment o f t h e geometry and
p r o p e r response.
(e)
C o n s i d e r a t i o n of See and Avoid Concept
91.67 o f the F e d e r a l A v i a t i o n R e g u l a t i o n s (Fm)
t h e burden on b o t h crews t o see and a v o i d o t h e r
aircraft.
Assuming d e t e c t i o n of t h e o t h e r a i r c r a f t , FAR
91.67(c) p l a c e d an a d d i t i o n a l r e s p o n s i b i l i t y on BuNo458 t o
r e s p e c t t h e r i g h t o f way o f RW706
Section
a/p l a c e s
Nonetheless,
as c a n b e a p p r e c i a t e d from t h e f o r e g o i n g
a n a l y s i s of t h i s c o l l i s i o n , t h e l i k e l i h o o d o f a p i l o t ' s
e i t h e r n o t s e e i n g a n i n t r u d e r a t a l l or s e e i n g t h e i n t r u d e r
and m i s i n t e r p r e t i n g v i s u a l c u e s and t h e n a t t e m p t i n g a n
e v a s i v e maneuver based on incomplete v i s u a l cues, i s h i g h l y
probable. The problem-solving p r o c e s s r e q u i r e d of p i l o t s i n
t h e s e s i t u a t i o n s is o f t e n h i g h l y complex, and i n many cases
the problem i s i m p o s s i b l e t o s o l v e i n t i m e t o a v o i d a
c o l l i s i o n . T h i s i s demonstrated by t h e f a c t t h a t t h e crew
of BuNo458 had r e c e i v e d r e c e n t t r a i n i n g i n l o o k o u t d o c t r i n e
and s c a n n i n g t e c h n i q u e s b u t were u n a b l e t o a v o i d t h e
collision.
Conversely, t h e crew o f EM706 r e c e i v e d no f o r m a l company
t r a i n i n g on l o o k o u t d o c t r i n e o r s c a n n i n g t e c h n i q u e s , and no
such t r a i n i n g i s r e q u i r e d by e i t h e r t h e company o r t h e FAA.
Although A i r West p i l o t s are e v a l u a t e d f o r * * a l e r t n e s s n , t h i s
evaluation
a p p e a r s t o encompass c o n d i t i o n s i n s i d e t h e
c o c k p i t a s w e l l as o u t s i d e .
There a r e no d e f i n i t i v e
c r i t e r i a t o d e t e r m i n e how e f f e c t i v e l y a p i l o t m a i n t a i n s a
proper lookout.
It may be argued t h a t p r e v i o u s m i l i t a r y
training
i n l o o k o u t d o c t r i n e and s c a n n i n q t e c h n i q u e s ,
coupled w i t h y e a r s of f l y i n g e x p e r i e n c e , would r e s u l t i n
excellent
t i m e - s h a r i n g f o r r e s p o n s i b i l i t i e s i n s i d e and
outside.
However,
it is e q u a l l y t r u e t h a t y e a r s
of
e x p e r i e n c e w i t h o u t c o n s t a n t review and improvement would
r e s u l t i n e s t a b l i s h m e n t and r e i n f o r c e m e n t of improper h a b i t
patterns.
Overcoming such a b e h a v i o r a l p a t t e r n , which
i n v o l v e s no c o n s c i o u s p r o c e s s , would r e q u i r e a c o n c e r t e d
r e t r a i n i n g program w i t h p e r i o d i c r e c u r r e n t t r a i n i n g .
The
Board b e l i e v e s it s i g n i f i c a n t t h a t t h e r e is no i n d i c a t i o n
t h a t t h e crew o f RW706 e v e r saw BuNo458 under t h e s e
circumstances.
The Board,
therefore,
reiterates
the
position
taken
many
times
before t h a t f o r c e r t a i n
o p e r a t i o n a l c o n d i t i o n s , t h e "see and avoid" c o n c e p t is
simply i n a d e q u a t e and t h e development of c o l l i s i o n avoidance
systems must b e v i g o r o u s l y pursued.
Whereas t h i s a c c i d e n t r e s u l t e d from h i g h c l o s u r e r a t e s
and, c o n s e q u e n t l y , s m a l l t a r g e t s i z e u n t i l s h o r t l y b e f o r e
t h e c o l l i s i o n , t h e Board a l s o r e c o g n i z e s t h e more common
t y p e o f m i d a i r c o l l i s i o n o c c u r r i n g between a i r c r a f t a t
r e l a t i v e l y low c l o s u r e r a t e s . The Board b e l i e v e s t h a t f o r
t h i s l a t t e r t y p e of c o l l i s i o n , t h e d e t e c t a b i l i t y
and
assessment
of t h e c o l l i s i o n t h r e a t from an i n t r u d i n g
a i r c r a f t can be enhanced by proper p i l o t t e c h n i q u e s and a
more thorouqh u n d e r s t a n d i n g of v i s u a l phenomena. The S a f e t y
r e l a t e d t o midair c o l l i s i o n s
Board's
publications
between a i r c r a f t i n v i s u a l m e t e o r o l o g i c a l c o n d i t i o n s have
viqilance.
stressed
the
need
for
increased
pilot
Recommendations have been s e n t t o t h e FAA, t h e a i r c a r r i e r s ,
commercial o p e r a t o r s ,
p i l o t a s s o c i a t i o n s , and t h e many
a v i a t i o n - o r i e n t e d i n t e r e s t groups t o i n c r e a s e t h e awareness
of p i l o t s t o t h e m i d a i r - c o l l i s i o n t h r e a t . I t is t h e r e f o r e
q r a t i f y i n q t o see t h a t many of t h e p r o f e s s i o n a l p u b l i c a t i o n s
and meetings of t h e s e o r g a n i z a t i o n s a r e f o c u s i n g on t h e many
f a c e t s o f t h i s problem.
a/
S i m i l a r l y , a t e r m i n a l c o n t r o l area h a s been implemented
i n t h e Los Anqeles a r e a , s i n c e t h e a c c i d e n t . T h i s a c t i o n i s
a p o s i t i v e s t e p toward r e d u c i n g t h e t h r e a t of m i d a i r
c o l l i s i o n s , b u t t h e Board b e l i e v e s t h e c o n c e p t would n o t
p r e v e n t t h e r e c u r r e n c e of t h i s a c c i d e n t .
E s t a b l i s h m e n t of
climb and d e s c e n t c o r r i d o r s , a s p r e v i o u s l y recommended by
t h e Board would t e n d t o e l i m i n a t e t h i s t y p e of a c c i d e n t .
2.2
Conclusions
(a)
Findinas
1.
Both a i r c r a f t were a i r w o r t h y .
2.
A l l f l i g h t c r e w members were q u a l i f i e d .
3.
RK706 was o p e r a t i n q i n accordance inith an
I F R f l i g h t p l a n under r a d a r c o n t r o l of t h e
Los Angeles ARTCC.
4.
BuNo458 w a s o p e r a t i n g i n accordance w i t h a
VFR f l i q h t p l a n and was n o t under c o n t r o l
of t h e ATC system.
The a i r t r a f f i c c o n t r o l l e r s were q u a l i f i e d
f o r t h e i r assigned d u t i e s .
BuNo458 w a s n o t d e t e c t e d on radar because of
an i n o p e r a t i v e transponder, t h e a i r c r a f t radar
cross-section, and a low l e v e l temperature
i n v e r s i o n i n t h e area.
There was no r e s t r i c t i o n t o i n f l i g h t v i s i b i l i t y
in t h e a r e a of t h e accident.
The p i l o t of BuNo458 exercised poor judgment
i n performing an a i l e r o n r o l l , but t h e r o l l
d i d n o t c o n t r i b u t e t o t h e accident.
The p i l o t of BuNo458 attempted t o e j e c t from
t h e a i r c r a f t , b u t he w a s unable t c do so because
t h e forward canopy d i d not j e t t i s o n .
I f BuNo458 had requested r a d a r t r a f f i c a d v i s o r i e s ,
t h e c o n t r o l l e r could have advised RW706 of t h e
presence of Bum458 and t h e p r o b a b i l i t y of
avoiding t h e c o l l i s i o n would have increased
significantly.
USMC f l i g h t c r e w s r e c e i v e t r a i n i n g i n lookout
d o c t r i n e and scanning technique.
No formal t r a i n i n g or evaluation of crew
scanninq technique and lookout d o c t r i n e i s
accomplished by A i r West.
Both a i r c r a f t were t h e o r e t i c a l l y cf s u f f i c i e n t
s i z e t o permit d e t e c t i o n by each o t h e r a t 35
seconds p r i o r t o c o l l i s i o n . However, d e t e c t i o n
and assessment were probably compromised by
t a r g e t s i z e due t o high c l o s u r e r a t e , t a r g e t
c o n t r a s t and l o c a t i o n i n t h e p e r i p h e r a l v i s u a l
f i e l d , and o t h e r v i s u a l l i m i t a t i o n s .
A t 35 seconds before impact, both aircraft
were on an e s s e n t i a l l y c o n s t a n t r e l a t i v e
bearing and would have been d i f f i c u l t t o d e t e c t
because each t a r g e t would be near t h e minimum
d e t e c t a b l e s i z e and would remain r e l a t i v e l y
stationary.
(b)
15.
I n view of t h e a b s e n c e of e v a s i v e a c t i o n
on t h e p a r t of RW706 (i.e., no a l t e r a t i o n
of heading, c l i m b p r o f i l e o r a i r s p e e d ) it
i s l o g i c a l t o conclude t h a t t h e c r e w
d i d n o t s i g h t EuNo458 i n time t o i n i t i a t e
such evasive action.
16.
The p i l o t o f t h e F-4B probably f i r s t observed t h e
t a r g e t of t h e EC-9 a t about 8 t o 1 0 s e c o n d s
p r i o r t o c o l l i s i o n , devoted t h e f i r s t p o r t i o n
o f t h i s b r i e f p e r i o d t o a s s e s s i n g such c u e s as
r e l a t i v e b e a r i n g , speed, and c l i m b a n g l e , and
i n i t i a t e d a r e f l e x e v a s i v e maneuver a p p r o x i mately 2 t o 4 seconds p r i o r t o t h e c o l l i s i o n .
Probable Cause
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 d e t e r m i n e s
t h a t t h e p r o b a b l e c a u s e of t h i s a c c i d e n t was t h e f a i l u r e of
h t h crews t o see and avoid e a c h o t h e r b u t r e c o g n i z e s t h a t
t h e y had o n l y marginal c a p a b i l i t y t o d e t e c t , a s s e s s , and
avoid t h e c o l l i s i o n .
o t h e r c a u s a l f a c t o r s i n c l u d e a very
h i g h c l o s u r e r a t e , comingling of IFR and VFR t r a f f i c i n an
a r e a where t h e l i m i t a t i o n o f t h e ATC system p r e c l u d e s
e f f e c t i v e s e p a r a t i o n of such t r a f f i c , and f a i l u r e of t h e
crew
of
BuNo458
t o request radar advisory service,
p a r t i c u l a r l y considering t h e f a c t t h a t
they
had
an
inoperable transponder.
3.
RECOMMENDATIONS
A s a r e s u l t of t h i s a c c i d e n t t h e 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 recommends t h a t t h e A d m i n i s t r a t o r of t h e
F e d e r a l A v i a t i o n Administration:
1. I n s t a l l v i d e o t a p e a t a l l FAA ATC
both
term_,ial
and
en
route
investigation tool.
(A-72-200)
radar
for
displays,
u s e as an
2. I n s t a l l an open " a r e a " microphone a t e a c h t e r m i n a l
and c e n t e r sector p o s i t i o n t o r e c o r d a l l c o n v e r s a t i o n
a t t h e control positions.
(A-72-201
3.
E s t a b l i s h climb and d e s c e n t c o r r i d o r s e x t e n d i n g from
t h e t o p of t h e T C A a s t o t h e b a s e of APC, t o remain i n
e f f e c t u n t i l t h e base of APC has been lowered t o t h e
t o p o f t h e TCA'S.
(A-72-202)
4. E s t a b l i s h more d e f i n i t i v e procedures f o r t h e guidance
of c o n t r o l l e r personnel i n handling
Code
7700
aircraft.
(A-72-203)
5. Review r a d a r performance monitoring procedures t o
a s s u r e t h a t a l l r a d a r f a c i l i t i e s a r e capable of
r e c e i v i n g Code 7700 transponder r e t u r n s .
(A-72-204)
The
National
Transportation
Safety
recommended (A-71-52)
that the FAA t a k e
action:
Board
also
t h e following
Coordinate with t h e Department o f Defense, and, i n a r e a s
where a l a r g e i n t e r m i x of c i v i l and m i l i t a r y t r a f f i c
e x i s t s , develop a program t o i n s u r e t h a t a p p r o p r i a t e
g r a p h i c a l d e p i c t i o n s of a i r s p a c e u t i l i z a t i o n and t y p i c a l
flow p a t t e r n s a r e prominently d i s p l a y e d a t a l l a i r p o r t s
and o p e r a t i o n a l bases f o r t h e b e n e f i t of a l l a i r s p a c e
users.
The F e d e r a l
Aviation
Administration
l e t t e r dated November 10, 1971, a s follows:
responded,
in
a
"This is i n response t o your s a f e t y recommendation, A-71-52,
i s s u e d 9 November 1971.
''Recommendation number 4 of our Near Midair C o l l i s i o n Report
of J u l y 1969 is similar t o your recommendation.
"As a r e s u l t of t h a t recommendation we:
1.
2.
Developed a new P a r t 4 of t h e Airman's
Information
Manual i n January 1970 (Graphic Notices and Supplemental
Information).
A s g r a p h i c s are made a v a i l a b l e , t h e y a r e
included in t h e semiannual P a r t 4 or a r e c a r r i e d i n t h e
every 28-day P a r t 3, u n t i l t h e y can be t r a n s f e r r e d t o
P a r t 4.
Developed v a r i o u s t y p e s of g r a p h i c
I F R and VFR routes.
displays
of
normal
3.
Developed g r a p h i c s f o r t h e 22 l a r g e t e r m i n a l hubs.
F i f t e e n a r e p u b l i s h e d in t h e A I M ,
and t h e remaining
s e v e n a r e i n v a r i o u s s t a g e s of p r o c e s s i n g .
4.
Developed g r a p h i c s f o r o t h e r t h a n l a r g e huks i n c l u d i n g
A i r Force Bases.
E i g h t a r e p u b l i s h e d i n t h e A I M and
t h r e e a r e i n t h e f i n a l s t a g e s o f development.
Nine o f
t h e e l e v e n d i s p l a y A i r .Force Base a c t i v i t i e s .
" I n a d d i t i o n t o t h e above, w e have developed a VFR Terminal
Area C h a r t (copy e n c l o s e d ) which w e w i l l be t e s t i n g and
e v a l u a t i n g . T h i s c h a r t o f Chicago Area d e p i c t s t h e Terminal
C o n t r o l Area, VFR and IFR r o u t e s and m i l i t a r y o p e r a t i o n s a t
NAS Glenview.
The c h a r t i s designed f o r u s e by p i l o t s and
f o r d i s p l a y a t a l l a i r p o r t s and o p e r a t i o n a l bases.
see, we have expanded upon t h e o r i g i n a l recommend a t i o n i n o u r Near Midair C o l l i s i o n Report. A s a c o n t i n u a t i o n o f t h i s e x p a n s i o n , we w i l l c o o r d i n a t e f u r t h e r w i t h t h e
Department of Defense t o i n c o r p o r a t e o t h e r m i l i t a r y bases
i n t o t h e program.
"As you can
" A f t e r r e v i e w o f t h e m a t e r i a l we have o u t l i n e d above, w e
would a p p r e c i a t e any f u r t h e r comments you may have conc e r n i n g t h i s matter. "
On February 8, 1972, t h e S a f e t y
mended (A-72-12 Â 13) t h a t t h e FAA:
Board
further
recom-
1.
Develop VFR Terminal Area C h a r t s , similar t o t h a t
p r o t o t y p e p o r t r a y i n g t h e Chicago TCA, f o r a l l o t h e r
T C A * s and, if f e a s i b l e , f o r o t h e r l a r g e a i r t r a f f i c
hubs.
2.
I n i t i a t e a program t o p u b l i c i z e t h e e x i s t e n c e of,
and t h e l o c a t i o n o f , t h e s e g r a p h i c s f o r p r o s p e c t i v e
users.
The program s h o u l d i n c o r p o r a t e , i n p a r t ,
Examoqrams and, i n airmen e x a m i n a t i o n s , q u e s t i o n s
r e f e r r i n q t o t h e s e graphics.
The F e d e r a l A v i a t i o n A d m i n i s t r a t i o n c o n c u r r e d w i t h t h e s e
recommendations i n a l e t t e r , d a t e d February 15, 1972.
O t h e r recommendations (A-71-48 t h r u 51) were s e n t t o t h e
Department of Defense on November 2, 1971, s u g g e s t i n g t h e
followinq actions:
1.
Review t h e f e a s i b i l i t y of r e s t r i c t i n g a l l t y p e s of
low-level t r a i n i n g , which r e q u i r e s a i r s p e e d s i n
excess of t h e FAR l i m i t a t i o n s , t o
designated
r e s t r i c t e d areas and low-level navigation routes.
2.
Rephrase t h e wording contained i n your a l t i t u d e /
a i r s p e e d l i m i t a t i o n s , and d e l i n e a t e
explicitly
t h o s e i n s t a n c e s wherein a i r s p e e d s i n excess of t h e
10,000 feet/250 X I A S l i m i t a t i o n s are authorized.
The Board b e l i e v e s t h a t t h e exceptions should be
l i m i t e d t o the following:
"a.
Climbs and descents t o t r a f f i c p a t t e r n s ,
authorized and/or designated t r a i n i n g a r e a s
and low-level navigation routes.
"b.
Those i n s t a n c e s where s a f e t y of e i t h e r crew or
a i r c r a f t r e q u i r e o p e r a t i o n s i n excess of t h e
limitation.
3.
Explore t h e f e a s i b i l i t y o f using t h e a i r i n t e r c e p t
radar on a l l m i l i t a r y a i r c r a f t t o provide c o l l i s i o n
avoidance a s s i s t a n c e a s an a d d i t i o n a l a i d t o t h e
"see and be seen" concept; and should t h i s prove
f e a s i b l e , i n s t i t u t e and e s t a b l i s h procedures t o use
t h e r a d a r f o r t h i s purpose on a l l f l i g h t s where its
use i s n o t r e q u i r e d f o r more urgent m i l i t a r y
mission requirements.
4.
I n s t i t u t e a program t o provide more p u b l i c i t y t o
t h e e x i s t e n c e , function, and use of t h e FAA Radar
Advisory Service in t h o s e i n s t a n c e s where VFR
f l i g h t i s required through high-density t r a f f i c
areas. Consideration should be given t o making t h e
r e q u e s t f o r such service a mandatory procedure."
The Department of Defense responded, in a letter dated
December 2, 1971, as follows:
" T h i s letter i s i n response t o t h e
National
Transportation S a f e t y Board s a f e t y recommendations A-7148 t h r u 51, which you forwarded t o S e c r e t a r y Laird on 9
November 197 1.
"These recommendations have been r e f e r r e d t o t h e
m i l i t a r y s e r v i c e s f o r t h e i r consideration. I am advised
t h a t during t h e i r i n i t i a l review t h e recommendations
w e r e c o n s i d e r e d sound and would be
implemented t o t h e
extent feasible.
The d e t a i l s of s u c h a c t i o n are b e i n g
staffed.
The r e s u l t s of this s t a f f i n g w i l l b e t h e
promulgation o f s p e c i f i c i n s t r u c t i o n s and q u i d a n c e t o
t h e i r o p e r a t i n g commands.
"Thank you f o r your h e l p f u l
recommendations
which
are so i m p o r t a n t t o o u r mutual i n t e r e s t i n a c h i e v i n g t h e
g r e a t e s t d e g r e e of a i r s a f e t y . "
The S a f e t y Board p r e v i o u s l y made recommendations on t h e
problem of m i d a i r c o l l i s i o n s i n t h e Board's s p e c i a l a c c i d e n t
p r e v e n t i o n s t u d y "Midair C o l l i s i o n s i n U. S. C i v i l A v i a t i o n
1968" which was r e l e a s e d in J u l y 1969, and t h e nReport of
P r o c e e d i n g s of t h e 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 n t o
November 4 through 10,
1969"
t h e Midair C o l l i s i o n Problem
which was r e l e a s e d February 22, 1971.
-
-
BY THE NATIONAL TRANSPORTATION SAFETY BOARD:
J O H N H. REED
Chairman
FRANCIS H. McADAMS
Member
ISABEL A. BURGESS
Member
WILLIAM R . HALEY
Member
LOUIS M. THAYER, Member, w a s a b s e n t , n o t v o t i n g .
September 2 2 ,
1972
FOOTNOTES
-I/
-21
-3/
A l l times h e r e i n
are P a c i f i c d a y l i g h t , based on t h e 24-
hour clock.
Airspace w i t h i n which a l l t r a f f i c i s under p o s i t i v e
c o n t r o l , and a l l a i r c r a f t must o p e r a t e in accordance
w i t h Instrument F l i g h t Rules (IFR). A t t h e time of t h e
a c c i d e n t , t h e p o s i t i v e c o n t r o l began a t F l i g h t Level
240.
c o l l o c a t e d v e r y h i g h frequency omnirange and u l t r a h i g h
frequency t a c t i c a l a i r n a v i g a t i o n a l aid.
The
DME
f e a t u r e g i v e s a s l a n t range measurement t o t h e f a c i l i t y .
A
-47
A c o n t r o l l e r q u a l i f i e d in the type of work being done,
i-e., r a d a r , data, tower, etc., b u t who i s n o t checked
o u t i n the s p e c i f i c p o s i t i o n o f a f a c i l i t y , i.e., R-18,
D-18, etc.
-57
MTI i s a f e a t u r e of t h e d i s p l a y which t e n d s t o e l i m i n a t e
r e t u r n s from s t a t i o n a r y t a r g e t s .
It i s i n f i n i t e l y
adjustable
within
the
range
capability
of t h e
radarscope, and has s i x p r e s e l e c t e d l e v e l s of s i g n a l
attenuation available.
-61
PRF was designed t o v i r t u a l l y e l i m i n a t e any b l i n d speed
e f f e c t which could occur when t a r g e t s a r e t r a v e l i n g
t a n g e n t t o t h e antenna, w i t h i n t h e range of the MTI
selection.
Such t a r g e t s would otherwise not appear on
t h e radarscope due t o apparent l a c k of motion.
-7/
Code 7700 i s
Â¥transponders
-8/
Guard channel is t h e i n t e r n a t i o n a l emergency frequency.
It is 121.5 MHz f o r very high frequency (VHP) communications.
-97
a
universally
used emergency code f o r
a p i l o t Warning Instrument
for
Visual
Airborne
Collision
Avoidance, S p e r r y
Gyroscope Company, G r e a t Neck, l o n g I s l a n d , December
1963: and Vision I n M i l i t a r y Aviation, J . W .
Wulfeck, e t
al., WADC Technical Report 58-399, November 1958, Wright
A i r Development Command, Wright-Patterson AFB, Ohio.
A Study of Requirements f o r
107
Foveal v i s i o n t a k e s p l a c e w i t h i n 200 of the c e n t e r
p o r t i o n (fovea) of t h e eye.
Peripheral vision occurs
o u t s i d e t h i s 200 cone o f f o v e a l v i s i o n .
117
-
FAR 91.67 s t a t e s i n p a r t :
"When weather c o n d i t i o n s
p e r m i t , r e g a r d l e s s of whether an o p e r a t i o n is conducted
under I n s t r u m e n t F l i g h t Rules o r V i s u a l F l i g h t Rules,
v i g i l a n c e s h a l l be maintained by each person o p e r a t i n g
a n a i r c r a f t so a s t o see and a v o i d o t h e r a i r c r a f t i n
compliance w i t h t h i s s e c t i o n .
When a r u l e o f t h i s
s e c t i o n g i v e s a n o t h e r a i r c r a f t t h e r i g h t of way, h e
s h a l l g i v e way t o t h a t a i r c r a f t and may n o t p a s s over,
under, o r ahead of it. u n l e s s w e l l clear."
FAR
91.67(c) p r o v i d e s t h a t :
"When a i r c r a f t of t h e same
c a t e g o r y are converging a t approximately t h e same
altitude
t h e a i r c r a f t t o t h e o t h e r ' s r i g h t has
t h e r i g h t of way.
II
... . . .
12/
-
Midair C o l l i s i o n s i n U.S. C i v i l Aviation-1960; A i r c r a f t
Accident Report NTSB-AM-69-2;
A i r c r a f t Accident R e p o r t
NTSE-AAR-69-4:
A i r c r a f t Accident R e c o r t NTSE-Am-70-15;
and Report of Proceedings i n t o t h e Midair c o l l i s i o n
Problem NTSE-AAS-70-2.
APPENDIX A
INVESTIGATION AND HEARING
1.
Investiaation
The Board r e c e i v e d n o t i f i c a t i o n of t h e a c c i d e n t a t
approximately 1830 on J u n e 6,
1971, from t h e F e d e r a l
Aviation Administration.
An
investigating
team
was
immediately
d i s p a t c h e d t o t h e scene of t h e accident.
Working qroups were e s t a b l i s h e d f o r Operations A i r T r a f f i c
Control, Witnesses, Weather, Human F a c t o r s , S t r i c t u r e s ,
Fowerplants, Systems, and F l i g h t Recorder.
I n addition t h e
maintenance r e c o r d s f o r each a i r c r a f t were reviewed.
The
Federal Aviation Administration, Department o f Navy, Hughes
A i r West, McDonnell-Douglas Corporation, and A i r Line P i l o t s
Association
all
participated i n the investigation a s
interested parties.
The
on-scene
investigation
was
completed on J u n e 19, 1971.
2.
Hearinq
A p u b l i c h e a r i n g w a s h e l d a t Pasadena, C a l i f o r n i a , on
J u l y 27 t o J u l y 30, 1971. P a r t i e s t o t h e Hearing i n c l u d e d
t h e F e d e r a l Aviation Administration,
Department of Navy,
Hughes A i r West, McDonnell-Douglas Corporation, A i r Line
Pilots
Association
and
Aircraft
Owners
and P i l o t s
Association.
A p r e l i m i n a r y f a c t u a l r e p o r t o f t h e i n v e s t i g a t i o n was
r e l e a s e d by t h e Board on J u l y 26, 1971. A summary of t h e
testimony was i s s u e d on August 20, 1971.
APPENDIX B
Crew Information
C a p t a i n Theodore Nicolay,
aged
50,
held
airline
t r a n s p o r t p i l o t c e r t i f i c a t e NO.
474317, w i t h r a t i n q s i n
H e had
a i r p l a n e m u l t i e n q i n e l a n d , F-27, DC-3,
and EC-9.
accumulated 15,490 t o t a l f l y i n g hours, i n c l u d i n g 2,562 h o u r s
H e completed h i s l a s t p r o f i c i e n c y check on
i n t h e DC-9.
March 8, 1971, and h i s FAA f i r s t - c l a s s medical c e r t i f i c a t e
was i s s u e d on J a n u a r y 25, 1971, w i t h no l i m i t a t i o n s .
held a i r l i n e
F i r s t O f f i c e r P r i c e Bruner, aged 49,
t r a n s p o r t p i l o t c e r t i f i c a t e No.
611777, w i t h r a t i n g s i n
airplane
multienqine
land,
F-27/227,
DC-3,
DC-9 and
commercial p r i v i l e g e s i n a i r p l a n e s i n g l e - e n g i n e l a n d .
He
had accumulated 17,128 t o t a l f l y i n g hours, i n c l u d i n g 272
H e completed h i s l a s t p r o f i c i e n c y check
h o u r s i n t h e DC-9.
medical
on December 7,
1970, and h i s FAA f i r s t - c l a s s
c e r t i f i c a t e was i s s u e d on Eecember 18, 1970, w i t h no
liiritations.
T h e f l i g h t c r e w members had been on d u t y a p p r o x i m a t e l y 6
when
hours, i n c l u d i n g a b o u t 1 hour 50 m i n u t e s f l i g h t t i m e ,
t h e a c c i d e n t occurred.
Their rest period p r i o r t o reporting
f o r d u t y was 18 h o u r s 13 minutes.
22,
Hostess
1959.
Joan
R.
P u y l a a r , aged 34, was h i r e d on August
H o s t e s s F a r t i c i a S h e l t o n , aged 28, w a s h i r e d on
18, 1963.
Hostess
16, 1967.
October
Helena Koskimies, aged 30, w a s h i r e d on October
A l l c a b i n crewmembers
completed
their
emerqency r e c u r r e n t t r a i n i n g i n September 1970.
prescribed
F i r s t L i e u t e n a n t James R.
Phillips,
aged 27,
held
commercial p i l o t c e r t i f i c a t e No. 1619834, w i t h r a t i n g s i n
H e a l s o held a v a l i d
a i r p l a n e s i n g l e - and m u l t i e n q i n e land.
H e had accumulated 440 t o t a l
fliqht instructor certificate.
m i l i t a r y f l y i n g hours, i n c l u d i n g 170 hours i n the F-4B.
He
a l s o had accumulated approximately 400 hours i n c i v i l
H e completed h i s l a s t Naval A i r Training and
aircraft.
Operating Procedures S t a n d a r d i z a t i o n s Programs
(NATOPS)
1970, possessed a Standard
f l i g h t check on December 8,
Instrument Card, and passed h i s annual medical examination
on June 23, 1970, w i t h no limitations.
F i r s t Lieutenant Christopher E. Schiess, aged 24, joined
S.
Marine Corps on November 7 , 1969, and completed
h i s R I O t r a i n i n g January 3. 1971. H e had accumulated 195
H e was
t o t a l f l y i n g hours, i n c l u d i n g 89 hours i n t h e I-4B.
c u r r e n t on a l l p r e s c r i b e d t r a i n i n g and passed h i s annual
medical examination on J u l y 13, 1970.
the U.
Both crewmembers had been on duty approximately 7 hours
4 minutes, i n c l u d i n g 1 hour 53 minutes f l y i n g time a t t h e
time of t h e accident.
T h e i r rest period p r i o r t o r e p o r t i n g
f o r this f l i g h t was 19 hours 10 minutes.
APPENDIX C
A i r c r a f t Information
s e r i a l No.
47441,
N9345, a McDonnell-Douglas DC-9-31,
w a s owned by t h e C.I.T.
C o r p o r a t i o n , 650 Madison Avenue, N e w
York,
N e w York, 10020, and o p e r a t e d by Hughes A i r West, San
F r a n c i s c o I n t e r n a t i o n a l A i r p o r t , San F r a n c i s c o , C a l i f o r n i a ,
94128.
I t had been flown a t o t a l o f 5,542 h o u r s a t t h e t i m e
A review o f t h e r e c o r d s i n d i c a t e d t h a t a l l
of t h e a c c i d e n t .
a p p l i c a b l e A i r w o r t h i n e s s D i r e c t i v e s e i t h e r had been complied
P r a t t 6 Whitney
with o r were scheduled f o r completion.
JT8D-7 e n g i n e s were i n s t a l l e d as f o l l o w s :
Position
S e r i a l Number
T i m e S i n c e Overhaul
The a i r c r a f t weighed 86,518 pounds a t e n g i n e start and
c e n t e r o f g r a v i t y w a s 21 p e r c e n t MAC.
Both are w i t h i n
t h e allowable l i m i t s .
the
Bureau Number 151458, a McDonnell-Douglas
F-UB,
was
r e c e i v e d on A p r i l 15, 1964, and had been o p e r a t e d by v a r i o u s
S. Marine Corps.
A t t h e t i m e of the
squadrons o f t h e U.
a c c i d e n t , it was a s s i g n e d t o VMFA-323, and had t e e n flown a
t o t a l of a p p r o x i m a t e l y 2,030 hours.
A review of t h e r e c o r d s
i n d i c a t e d t h a t t h e a i r c r a f t w a s maintained i n accordance
w i t h t h e appropriate regulations.
General Electric J79-8
e n q i n e s were i n s t a l l e d a s f o l l o w s :
Position
S e r i a l Number
Time S i n c e Overhaul
The a i r c r a f t weighed approximately 43,310 pounds a t
engine s t a r t . B o t h the takeoff weight and center of gravity
were within prescribed l i m i t s .
Intentionally Left Blank
in Original Document
ATTACHMENT 2
COMPUTED RANGES, BEARINGS, A N D C L O S U R E RATES
PRIOR TO EVASIVE MANEUVER
DC-9-31
TRUE NORTM
145- MAG
4 0 0 ~TAS
I FIT RECORDER I
420K TAS
IRIO TESTIMONVI
I C NORTH
,/
Intentionally Left Blank
in Original Document
PTAIN'S SIDE WINDOW
LEFT
RIGHT
40 sec
60 sec
80 sec prior
DC-9 VISIBILITY FROM CAPTAIN'S DESIGN EYE
REFERENCE POINT
-Â
- 5m
>
-10-
A
<
u
-15-
IÃ
K -20w
>
-25-
2
3
0
WINDSHIEID
F-4 CALCULATED
FLIGHT PATH
co-PILOT'S
SIDE WINDOW
CAPTAIN'S
FRONF WINDSHIELD
-30CO-PILOT'S
SIDE WINDOW
CLEAR AREAS REPRESENT
BINOCULAR VISION
Intentionally Left Blank
in Original Document
LATERAL VISIBILITY
25-
5
20-
w
.
DEGREES
---
VISIBILITY I S COMPLETELY OBSCUREDs.
v,
-
VISIBILITY FROM RIO'S DESIGN EYE REFERENCE POINT
1
4
0 SEC PRIOR TO COLLISION
60 SEC PRIOR TO COLLISION S,
20 SEC TO 3 SEC PRIOR TO COLLISION
10-
fc^
in
--5
3
--to
--I5
1 I
5-0-
>
_, Z
0
NATIONAL TRANSPORTATION SAFETY BOARD
WASHINGTON, O.C.
/
ZERO REFERENCE'
--30
LFFT
140 130 120
110
100
90
80 7 0
60
50
40
30
20
10
0
10
20
30
40
50
60
RIGHT
70
80
90
100
110 120 130 140
l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l
LC
LATERAL VISIBILITY
-
DEGREES
4.6
HUGHES AIR WEST DOUGLAS DC-9-31, N9345
U.S. MARINE CORPS F-40, BUN0 151458
MIDAIR COLLISION
NEAR OUARTE, CALIFORNIA
JUNE 6, 1971
-
4
7
Intentionally Left Blank
in Original Document