C I V I L A E R O N A U T I C S B O A R D File No.

A I R C R A F T ACCID€NT REPORT

ADOPTED: January 6, 1960 RELEASED: January 10, 1960 I

AMERICAN AIRLINFS, INC., LOCKHEED ELEC'FRA, N 610U, IN THE EAST RIVER, LA WARDIA AIRPORT, NEtl PORK,

FemARY 3, 1959

SYNOPSIS

A t approxlmtrtely 2356 e. s. t., on February 3, 1959, an American Airlines Lockheed Electra aircraft crashed into the East River while attgmpting an inst ru- ment approach t o runway 22 at La Ouardia Airport.

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There were 73 persons on board, including one infant. The captain and one stewardess were ki l led; the first off icer , f l i g h t engineer, and the remaining stewardess survived. Of t he 68 passengers, survived. To da te 63 bodies have been recovered including the bodies of the captain and one stewardess; two others )re still missing.

result of preoccupation of the crew on part icular aspects of t h e aircraft and its environment t o t h e neglect of essential f l i g h t instrument references fqr attitude and height above the approach surface. limited experience of the crew with t h e aircraft type, faulty approach technique i n which t h e autopilot was used i n the heading mode t o or almost t o t h e surface, erroneous s e t t i n g of tFe captain's altimeter, marginal weather i n t h e approach area, possible misinterpretation of alt imeter and rate of descent indicator, and sensorg i l l u s i o n with respect t o height and a t t i t ude resul t ing from visua l reference t o the few l i g h t s eA,sti.ng in the approach area.

The Board believes that a prmature descent below landing minimums was the

Contributing factors were found t o be;

As a result of this accident, t he Federal Aviation Agsncy, on February 8, 1959, as a precautionary measure, raised ELectra landing m i n i m u n s . of the comentional three-pointer altimeter, the r e s t r i c t ions were l i f t ed .

Upon the in s t a l l a t ion

The Board has recommended t o the Federal Aviation Agency t h a t autopilot approach c r i t e r i a and Limitations a?plicable t o all air carriers should be estab- l i shed , taking in to account t he par t icular autopilot used, t he aircraft involved,. and t he approach f a c i l i t i e s ut i l ized. t h a t all air ca r r i e r s should establish simlator t ra in ing programs prior t o putting i n t o service aircraft which require the acquisit ion and application of significantly di f fe ren t .operational techniques; and t h a t a l l large turbina-engine aircraft used i n air transportation be equipped with a f l i g h t recorder.

The Board has also recommended t o the FAA

IHVESTIGATION

The Flight

February 3, 1959, was scheduled t o depart Chicago Midway Mrp0p02i2t2%$ It was loaded, dispatched, and operated t o the New Ysrk area routinely i n amordance wi th the applicable company and Civil Air Regulations. An instrument fUght plan va8 f i l ed u i t h t he company and clearance was approved by Air Route !traffic Control. The aircraft was off t he ground at 21% and estimated one hour and forty-two minutes en route t o New Pork, Cormmrnications with the cmpany and Air R o u t e Traffic Control were routine.

A t 2327~55, approximately one and one-half hours after departure, Flight 320 made i t a f i r a t transmission to La Guardia approach control, A f t e r contact was estab-: lished, the f l i g h t reported it was at 9,000 feet approaching Somerset (Pennsylvania) intersection.

A t 2328843, Fl ight 320 reported Over the Somerset interoection, A t 2333:39,

ameasured four hundred overcast; a mile and a quarter visibility; l i g h t

pl ight 320 reported northeast bound on Amber 7 Birway and w a s ident i f ied by La hardier radar. A t 23%:03, Fl ight 320 w a s issued t h e 2331 La Guardia weather aa follows; rain and fog; the v i s i b i l i t y south and t o the northwest reported at two miles; wind is southwest a t three, altimeter is dropping; it is now two nine seven eight." The latest La Ouardia weather was given to Flight 320 on two other occasions, a t 2328:lO and at 23bh39.

During t h e period 2339:Ol t o 2%9:35, Fl ight 320 was given heading and d t i k d e changes t o increase its separation from a preceding m-3, and was vectored t o - t h e back course of t he aS while descending frm 8 ,ooO t o 1,500 feet. message was transmitted t o F l ight 320 at 2%4:39, #Roger, now the latest La Guardia weather, out at th i r ty-e ight past the hour, t he time is forty-four past the hour; i t*s nsasured four hundred overcast; two miles v i s i b i l i t y , l i g h t r a in and fog; a l t i - meter two-nine-nine-seven. Correction, t h e alt imeter is two-nine-smen-seven, two- nine-seven-seven, La Guardia altimeter." A t 2%5:43, Flight 320 w a s advised tha t another aitcraPL had previouplly missed its approach,

The folloving

A t 2352823, Fl ight 320 reported t o approach control that it had passed New Rochelle and approach control requested the f l i g h t t o contact the La Guardia tower on 118.7 mcs. f o r 8 straight-in approach t o runway 22g/. A t 2353:00, the f l i g h t reported to La Ouardia tower as having passed New Rochelle, A t 2354:37, Fl ight 320

All t i nea herein 8 ~ 8 eastern standard based on the 24-hour clock, shown i n

21 In i t ia l approach procedure prescribed an a l t i t u d e of 1,500 feet as1 10 miles

hours, minutes, and seconds.

northeast of New Rochelle inbound for runway 22, t o pass N e w Rochelle at minimum of 1,000 feet afl, descend t o a minimum of 800 afl over t h e La Guardia range s ta t ion, and continue descent to 400 feet afl al t i tude. landing may be effected, and one m i l e . )

If contact i s (Day and night company minimums

(as1 - above sea level; afl - above f i e l d level)

established a t this poi&, a f o r runway 22 are 400 feet

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reported over the La Guardfa range wfiich is 2.8 nautical miles f 'rom the threshold of m a y 22, and 4.8 nautical miles fmm New Rochelle, to continue its approach t o runway 22, and was requested t o stand by for further clearance. A t 2355:20, F l i g h t 320 was cleared to land straight in on runway 22, wind south-southwest 8 knots. There was no fur ther message *om the f l i g h t .

A t 23%:40 it was cleared

A t 2355:27, the f l i g h t acknowledged by saying 920."

The crash occurred approxbately seven seconds following the f i n a l message. Most of the wreckage was found suherged within a 200-foot radfus circle, the center of which was located approximately b,891 feet short of the threshold and 610 feet to the r igh t of the extended csnberline of runway 22..

According to the testimony of the crew, the takeoff and climb from Chicago w a s

Since it did not operate correctly in t h i s posi t ion it was switched

The f l i g h t was on and off instruments at a cruising altitude of 21,000 fea t ,

routine. mode position. to heading mode2/ which operated satisfactorily and was used throughout the en%irer tr ip, The pitot heaters were on during the entire f l i g h t .

The autopilot was initially engaged sometime during climb-out in the m m d l

Some ice was encountered during descent approaching the New York area. Howmer, it was o f short duration, so the captafn elected not to use the wing heaters, After passing N t m a r k Intersection, a thirty4egrea error was reported by the first officer on US RMDI (radio magnetic direction indicator), However, radar vectoring and m-

The aircraft was flown in the New York area at an airspeed of 175 knots OF less

&etic compass indica'biana revealed the captain's RWI was operating satisfactorily. \

with approach f laps. cepting the localizer course inbaund except for landing flaps, heaters, landiw l ights , and autopilot which are accomplished later in the landing approah. landing gear was extended at N e w Rochelle and t h e airspeed from New Rochelle inbound was approximately &O knots.

The "before landingu checklist was accompliahed prior t o htm-

The

The first officer stated that during the approach to La Ouardia, the ILS switch W 8 5 i n the back course position; sensitivity switch "not desensitised," and a recip- rocal heading of t he f ront course localizer of deviation indicator window, was in the heading mode, ateering needle mode selector knob was in the deviafiozl poettion, both VHP navigational recekvers were on t he La hsrdi8 as, the Captain*$

officer's to New Rochelle compass locator and, after passing that point, retuned to the La Guardia range,

degrees was set up in the Q w r S 8 The ADF selectors were in ADP position, the autopilot

was tuned to the compass locator a% the middle marker (La Quardia), the first

The surviving f l i g h t crew members t e s t i f i e d t h a t during t h e approach, the captain was f ly ing the a i rcraf t by the autopilot; the first officer waa handling the communications and assisted the captain; the f l i g h t engineer. was h a w the throttles and maintaining approximately a0 knots on the captain's airspeed indi~ator,

Heading mode is a position on the autopilot control panel that al low8 the t t o receive heading information f rm the captain's course deviation indi-

If a new heading is desired, the captdn need only reset the hesdhg qqtor ody.

tain t h i s new heading. rotating the heading knob, The autopilot v & l l t u rn the airplme to md m a i n -

- 4 - The first officer stated he received his altimeter se t t i ng from company

radio and t he three crew members corss-checked the altimeters when the item w a s called f o r on the landing checklist, resetting his alt imeter after receiving a transmission from La Qaardia tower. setting was 29.77. when passing the La Guardia range inbound at an a l t i t ude of 900 feet. meters indicated approximately t h e same.

The f l i g h t engineer r e c a l l s t h e first o f f i ce r The

The altimeters were cross-checked again by the first of f icer Both alt i-

The first of f icer stated tha t after passing the range s t a t ion the captain momentarily increased the rate of descent t o approximately 600400 feet per mimte and then decreased it t o about tbe normal rate of 200 t o 300 feet a minute. f l i g h t engineer &IXI noted the captain actuate the autopilot p i tch trim wheel in the "downw direct ion j u s t p r ior t o impact. 135 t o 3.45 knots on the captain's instrument. ment by t he f l i g h t engineer; t h e horsepower ranged from 900 t o 1,200. officer stated t h a t at 600 f e e t on his alt imeter he called out 600 and an airspeed of 135 knots. beluw the level of the cockpit and before he could look back t o his instruments t o call out w500 feet ," 'they struck the water.

During t h e investigation, t h e first surviving crew member t o be interviewed pr ior t o t h e public hearing was F l i g h t Engineer Warren E. Cook. Mr. Cook first stated t h e captain's drum altimeter read, Yetween !aero and t h e 100-foot mark on the drum" when t h e a i r c r a f t &m& the water , and subsequently, during the same interview, cl-ied this statement, after being reminded t h a t the drum reads in thousands of feet, t o state t h e a i r c r a f t struck t h e water when the hand of t he alti- meter was on about 500 feet 89 fa r as he could recall. F l i g h t Engineer Cook had approximately 8,700 f ly ing hours, 81:29 hours of which #ere i n Lockheed Fllectra air- craft, a l l of which were equipped wi th drum-type altheters. mately 190 private p i l o t hours i n small aircraft.

?he

The airspeed was maintained i n t h e range of There was vary l i t t l e t h r o t t l e move-

The first

He glanced out h i s r i g h t side window, s a w some red l i g h t s j u s t a l i t t l e

He also had approxi-

Later, the f l i g h t engineer testified t h a t as he glanced out the captain's side window at a'ouut 600 feet on the captain'8 altimeter, he obseroed 3 o r 4 whi te l igh t8 and thought the aircraft w a s unusually low. He immediately looked a t the captain's alt imetbr and it was indicating a l i t t l e above 500 f e e t when the accident occurred.

Both f l i g h t crew members stated tha t visual contact was never established through the forward windshield. re t racted and off, flaps i n approach position, and the autopilot was still engaged&/ No warning l i g h t s were obsemed, the a i r c r a f t and engines operated normally, 2nd there w a s no indication of a stall, pitch, yaw, or abrupt maneuver.

The windshield wipers w e r e off , the landing l i g h t

tnesses - The sunriving stewardess and four passengers stated t h a t p r io r t o the crash

the sea t belt s ign and no smoking sign were uon.m

"The dfore landing check should be made after reporting i n range. On instrument approaches, it should be completed pr ior t o crossing range or radio fix on i n i t i a l approach, o r p r io r t o leaving a holding poin t f o r f i n d approach." The f i n d ita of the before-lxiding checklist is nauto-pilot-off.n directives wi th respect t o the use of autopilots i n various types of instrument approaches .

The stewardess had wade t he

4 American Airlines R e c t r a Operating Manual, Section 3, Page 34, states that:

FAA has not issued any policy

routine before-landing check and foundtha t the passengers had canplied with the instructions. The feel ing of the survivors in the rear of the aircraft was as if a normal descent w a s being made f o r a landing.

Upon s t r ik ing the water, a crash impact l i g h t was observed inside the cabin. However, one of t h e passengers advised t h a t he was unable t o read t h e instruct ions for opening the emergency door. The stewardess advised the passenger t o pul l i n on the door and it opened.

The crew of Northeast Airlines DC.13, Flight 383, which preceded Fl ight 320 by about 2 minutes, s k h c k t h a t they crossed New Rochelle a t an a l t i t ude of 1,500 feet . A st raiglx- in approach t o runway 22 was executed crossing the range a t 800 f e e t and then-descending t o 400 feet, After 10 to 15 seconds a t boo f ee t , t h e f u l l length of t he m a y became v i s ib l e t o them and a normal descent was started and landing effected.

One ground witness i n a car on the approach t o Whitestone Bridge described h i s observations of a large a i r c r a f t crossing the highway at about 2353, a t an estimated altitude of about 100 fee t . he stated t h a t the markings on t h e a i r c r a f t were red and black. termine whether the landing gear was down but did state t h a t t h e a i r c r a f t was i n a s l igh t ly n o s e d m at t i tude.

He s a w t h e whole belly and t h e l i g h t s on t h e a i r c r a f t and He was unable t o de-

A member of the crew of t h e tug H. Thomas %ti, stated he saw the a i r c r a f t &en it was abuut ttm t o aJxhuspd;rtxi feet horizontally from the tug and about 1 2 f eet*abave the water. Aceerrding t o the capta-in of t he tug, the Teti was proceeding southwesterly i n the channel on radar toward the approach end of runway 22. It was approximately 4,100 f e e t f r a m the end of runway 22, and about 850 f e e t t o the l e f t of t he centerline extended of runway 22. A crew m e m b e r saw the aircraf't crash and at the time he didn' t notice any l i g h t s on it. He sa id tha t it contacted t h e water at an angle of about 5 degrees nosedown,

Weather

A t the time of the accident, a low press'ure center was located near Cape Hatteras and a trough extended northward from this center i n t o the Ne@ York C i t y area. Forecasts had underestimated the rap id i ty of the northward surge of warm air along t he Atlantic caas ta l area i n association with the shallow low pressure trough described above. b i l i t i e s and i n the winds a l o f t observation a t Idlewild (2/4/59, 0100 e.s.t.) which read i n part as follows: Surface - southerly 6 knots; 1,000 feet - 190 degrees 3, knots; 8,000 feet - 1% degrees 50 knots; 3,000 feet - 200 degrees 60 knots.

This surge of waxm air was reflected i n louered cei l ings and v i s i -

!he latest weather observation at La Guardia prior t o the crash vas taken a t 2352. A t this time, the ce i l ing was a measured 400 feet (variable), t h e sky w a s overcast; V i s ib i l i t y 2 miles in l i g h t r a i n and fog; temperature 37; dewpoint 35; wind south-southwest 6 knots; and the altimeter se t t ing was 29.76. ciated with the above observation, t he ceiling was indicated aa 400 variable to 300 feet and t h e pressure was indicated as f a l l fng rapidly,

The crew of M, DC-3, landing at La OLlardia two minutes pr ior t o t h e accident, ver i f ied the ceiling and v i s i b i l i t y values given i n t h e above observation.

I n remarks asso-

Some members of the tug crew mar the crash si te and cer ta in ground witnesses described very r e s t r i c t ed vis ibi l i ty conditions abcme the surface of the r i v e r and mer the land areas north of t he river.

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The l a s t altimeter se t t ings fo r La Guardia given t o the crew of Fl ight 320 cmpany radio about one hour prior t o t h e crash were 29,85 and plus 90, whereas

a t the time of t he crash the altimeter setting was 29.75. I Other a i r c r a f t approaching La Ouardia short ly before and af'ter the accident

did not report icing d i f f icu l t ies . a temperature inversion of increasing proportions,

%e rapid influx of warm air a l o f t was causing

Airport and Facilities

Investigation revealed t ha t a l l required airport, h n d a r y , and runway l i g h t s a t La Guardia were on,

Subsequent t o the accident and i n accordance with standard procedures, the FAA conducted an immediate ground check of all navigation facil i t ies serving La Guardia. The following day these f a c i l i t i e s w e r e also f l i g h t checked and found t o be function- ing normally. The crew o f the NEA DC-3, which preceded Fl ight 320 on the backcourse ILS, reported tha t a l l f a c i l i t i e s were operating normally.

Aircraft Structure

More than 90 percent of t h e primary s t ruc tura l ccmponents of the a i r c r a f t and t h e majority of t he systems components (hydraulic, pneumatic, air-conditioning, e l ec t r i ca l , etc.,) were recovered.

The l m e r surfaces of N 610lA showed a general d i s t r ibu t ion of water impact damage which w a s sapnewhat more severe on the r i g h t than on the lef t side. Water impact broke all t h r e e landing gears rearward and to re off the landing gear doors and wing f laps , attached, broke away, floated, and w e r e recovered separately., fuselage be l ly was completely destroyed by the water impact and very 1ittJ.e of it was recovered.

The landicg gear shock s t r u t pistons, with t h e i r wheel assemblies The lower forward

Ihe fuselage s h e l l above the f loor l ine was broken in to four general sections; t he cockpit, the forward passenger cabin, the center passenger cabin, and the aft passenger cabin with the t a i l cone and vertical t a i l surfaces still attached, The l e f t and r igh t s ides of the forward and center cabin areas were to rn apart either by t h e impact or during recovery, The en t i r e cabin f loo r was broken up i n t o small pieces except i n t h e extreme aft end where it was.trsrn p a r t i a l l y loose and buckled upward i n the center. except i n the extreme aft end of the cabin. sides of the a i r c r a f t were broken off upward j u s t outboard of the fuselage, elevators remained attached t o the stabilizers.

All seats were broken out of t h e i r s t ruc tura l attachments

"he The horizontal t a i l surfaces on both

The wings were broken i n to four main sections. These were the two outer panels with the ai lerons and outboard nacelles attached, and the two inboard nacelles with t h e i r i n t eg ra l wing st ructure and broken main landing gears, leading edge of the r i g h t wing outboard of number b engine received severe water impact damage and t h e wing tip was to rn completely off. outer panel only had a srnLdl area of water i;pact dcmage near t h e aft edge of the lower surface of t h e King t i p .

The

In contrast, the left Wing

The wing s t ructure between the nacelles on each side and inboard through the fuselage was completely shattered and w a s recovered i n small pieceso

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A t the impact the landing .gar was extended, the flaps were in approximately the approach position,' and t he r i g h t landing l i g h t was re t racted, light waa not recovered.

The le f t landing

The Board has conducted an investigation of the crash in jurg aspects of this accident, t h e results of which will be t h e subject of a subsequent Board raoort.

Pwerplants and Propellers

The comparatively lengthy submersion i n the East River resulted i n corrosion Neverthe- and contamination throughout the engines, propellers, and accessories.

less, accurate determination of the condition of the part8 and components pr ior t o impact wae readily accanplished.

Sumiving crew members testified that a l l powerplants were functioning normally u n t i l t he moment of impact, follaring disassembly confimed t h i s testimony. Engine and WopeUer o i l systems were free of s igni f icant contaminants, There was no preimpact damage, foreign object damage, or evidence of over-temperature, Examinatton of detailed parts, including bearings, accessory drives, o i l pumps, and components of the reduction gear assew blies, d id not show any t o have f a i l ed during engine operation.

Propeller blade angles were rellatively uniform and averaged approximately 36 degrees.

concerning horsepower being used during the approach.

Detailed examir,ation of the engines and propellers

This blade angle when related t o power i s consistent with power read- 'ings obtained frm the recovered a i r c r a f t instruments, and the crew's testimony

Flight Instruments

All recovered instrument and instrument system components had been submerged i n salt water f o r periods of time ranging from about ninety-four hours t o twelve days, They were comoded, and many suffered fmm impact damage. All uere inopera- tive with the following exceptions: The captain's horizon direct ion indicator, the two di rec t iona l ggros, t h e autopilot control panel, the two s t a t i c selectors, t h e three-axis t r i m indicator, t he two fluxgate transmitters, and t he clock on t he captain's i n s t m e n t panel, uhich uaa still operating a t t h e of recovery.

The two instantaneous v e r t i c a l speed indicator instrument casings were st i l l attached t o t h e i r respective panels and r e l a t ive ly intact , but the instrument mechanisms were missing and were not recovered. Only one instrument face w a s recovered .

The altimeters installed on the instrument panels of N 610lA were Kallsman, type A-28586-10.001, pressure drum type, having a range of from minus 2,000 feet to 50.000 feet al t i tude. diaphragms which, i n response t o changes i n atmospheric pressure, expand and con- t r ac t . This expansion and contraction is transmitted t o a pointer by means of a

The pointer makes one revolution f o r each 1,OOO f e e t of

The heart of t h i s altimeter consis ts of two matched

. ?inkage and gear system. --alt i tude chwgc, and two concentric drms measure the nua'mr of turns of the pointer and accordiwly indicate t h e 1,000-foot flight levels. metric setting t o carredate a l t i t u d e indication with the prevailirig atmospheric pressure i n a manner similar t o t h a t eanployed i n conventional three-pointer alti- meters except that the numerical values of t he se t t i ng appear in reverse order.

Provision is made for baro-

E3etctra N610lA had approximately 302 hours of f l i g h t time since manu- factured durjng a l l of which the drum type a l t h e t e r s installed had operated sa t i s fac tor i ly . Of the 362 hours of f l i g h t t h e , approximately 150 hours had been flown pr ior to dellvery t o American Airlines.

m o r t o departure of Flight 320 from Chicago, the alt imeters were checked by the crew and were reported operating sa t i s fac tor i ly ; also, during the f l i g h t they appeared t o be operating sa t i s fac tor i ly . Durhgletdown on approach t o mn- way 22, both altimeters were reportedly cross-checked at 900 feet and again a t 600 feet,

The dnua althetars in N 610.l.A were calibrated pr ior t o delivery by t h e manu-

Ecamination and t e s t ing of these altimeters subsequent t o the accident facturer, ICoIlman Instrument Corporation, according to accepted government-industry standards. did not reveal any mechanical f a i lu re s other than those a t t r ibu tab le t o impact, shock, and immersion in s a l t water. When the wreckage was'recovered, t h e captain's altimeter read m i n u s one thousand five hundred feet, with a pressure a l t i t u d e setting of plus 85 f e e t (barometric s e t t i ng 29.83). The first of f icer ' s a l t imeter read minus one thousand six hundred and fifty feet, with a barometric s e t t i ng of 29.79.

Chemical analysis of the contents of t he casings of the captain's and the first of f icer ' s altimeters discloaed t h e presence of hydrated dumirnun oxide and sea water, with traces of iron and other metallic elements ordinar i ly found i n sea water, No marks were found on t h alltfrneter faces t h a t could have been caused by impact of t h e pointers. not broken.

The glass coverings of the faces of the two alt imeters were i n pilace atxi

Before opening the caeinga of the altimeters f o r examination of t h e i r internal mechanisms, it WBS found t h a t the manufacturer's lead seal, which en t i r e ly covers t h e head of one of t h e screws t h a t secures the casing on the altimeter, w a s missing from t he captain's altimeter, instnrment has been returned t o the manufacturer with a complaint, f o r overhauling, o r adjustment, whether t he altimeter had been opened since its delivery t o the purchaser,

The purpose of this seal. is t o determine, when an

In te rna l inspection of the alt imeters revealed considerable corrosion)within each of the instrumente. a rocking s h a f t pivot W(LL( found broken I n t h e first Officer's altimeter. sfon was rammed t o perni t a detailed inspection of t he moving parts. The broken component8 were replaoed, after which both i n s t m e n t s were checked f o r mechanical freedom and were found to operate without s ignif icant r e s t r i c t i o n over a range of minus 1,000 feet t o 12,000 f e e t o

A broken link pin waa found in the captain's altimeter and The corro-

Since t he diaphragm of both alt imeters were overstressed due t o submersion, it was impossible t o establierh a ea l ibrs t ion curve which would be representative of t h e ca l ibra t ion of the altimeter before t h e crash,

stati'c Pressure System

first officer's f l igh t , i n s t m e n t s , r e~~pec t ive ly , is also provided as an emergency 8ource of pressure t o which either or -mth sets of f l i g h t instruments may be connected by means of s t a t i c system selectors ,

Rro separate s t a t i c systems supply barometric pressure t o t he captain's and A turd (ab-temate) static system

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The captain's and the first of f icer ' s s tatic selectors wer6 found i n normal positions; both w e r e guarded and operable. A l l connections t o the static manifold and from the manifold t o t h e static selectors were proper. from the s t a t i c seleotor valve8 were properly connected with t h e a i r c r a f t piping.

accident using a B-29 Air Force ic ing tanker, a tes t ELectra, and a chase R e d r a for photographic purposes. F l igh t tests duplicated airplane speeds, configurations, and 0utSid8 a i r temperatures, which existed during the f i n a l approach of F l i g h t 320 t o La Guardia. The tests showed tha t ice buildup on the fuselage w a s confined t o t h e forward section and did not approach the area of the static ports, even when t h e test airplane w a s yawed drast ical ly . Ground tests on an Klectra fuselage sect ion which Included the s t a t i c ports were run t o simulate careless washing, splashing of a f l u i d solvent on a cold f'uselage, and a leak i n the nose wheel mU. These tests d i d not induce any signif icant instrument errors. Under the most dras t ic test, t ha t of a suction induced by twin hemispheres i n the v i c i n i t y of both s t a t i c ports on opposite sides of the a i r c ra f t , t he altimeter error w a s approximately 175 feet at an airspeed of 135 knots. It is important t o note t h a t t h i s venturi effect was man- nads and, so far as is known, is not reproducible naturally,

Uintenance

The flex-hose msemblies

Simulated ic ing tests were arranged by the Board and m n subsequent to t h e

The maintenance records f o r American Airlines, N 6101~, were reviewed and it found t h a t they w e r e complete and showed t h a t the required maintenance had been

.arfomed,.that the wmpltt5nt entries of an airuorthiness nature were corrected, and ;hat they were properly signed off. The aircraft had been f lown a t o t a l of approxi- lately 302 hours.

'raining

Captain DeWittfe Electra ground school t ra in ing was completed on December 4, 958, at Fort Worth, Texas. hich 6 8 ~ 3 0 hour8 uere devoted t o aircraft systems and l6 hours t o operations and erf ormance.

The course consisted of 84:X hours of instruction, of

An Electra simulator was not avai lable but Captain I ) e W i t t did receive t ra ining n a Unk t r a ine r equipped with t h e f l i g h t director system similar t o that installed n t h e ELectra but not having drum-type altimeters or instantaneous vertical speed ndioators. According t o American Airlines ' records, Captain B W i t t , during December 958, aompleted five hours of Unk t ra in ing u t i l i z i n g the f l i g h t d i rec tor system.

Captain DeWitt'cc f l i g h t t ra in ing i n Electras commenced December 11, 1958. msisted of day and night takeoffs and landings, airwork, autopilot operation, nergency procedures, and s y s t e m operation. Bok his first type rat ing f l i g h t check wi th an FAA inspector after 8:07 hours of .ectra t ra ining, 'Ihis check consisted of required manewers and navigational pro- .ems, holding a t a fix, 2-engine out IIS approaches, crosswind takeoffs and landings, id c i r c l ing approaches simulating 400 feet and one mile v i s ib i l i t y . Sled t h e portion of the check which required him.to perform an Us approach a i m - ,tting a 200-foot ce i l ing and one-half m i l e visibility w i t h engines Nos. 1 and 2 duced t o zero thrust . 58, with a total of 11:59 hours of Electra training, successfully passed his type tine; check and an instrument check.

This

On December 15, 1958, Captain D e W i t t

Captain D e W i t t

After additional practice, Captain D e k j i t t on December 16,

- 10 - Captain D e W i t t had acquired a *&al of 48:13 hours i n Electra aircraft at

the time of t he accident. After completion of Electra t r ans i t i on training, he also flew approximately 14 hours i n DC-6 and DC-7 aircraft before being assigned to electra l ine operations on January 25, 1959.

The American Airlines F l igh t Manual requires the cei l ing and v i s i b i l i t y landing minimums prescribed i n t h e Operations Specifications - Airports, t o be increased by 100-feet ce i l ing and one-half mile visibil i ty whenever t h e captain i n scheduled operation has not served f o r 100 hours as pilot-in-command on the equipment, or u n t i l such time as the captain is certified by h i s Regional Super- intendent of Flying, aa qualified t o operate a t the landing m i n i m s prescribed. The company had check p i l o t s r i d e with all captains on Electra equipment unt i l they were qual i f ied for lower mi-8. of Flying authorized t h e removal of these r e s t r i c t ions on Captain D e W i t t January 25, 1959, when he had 12:32 houra of flying the ELectra i n scheduled operations,

The American Airlines Regional Superintendent

Ihe correct procedure f o r making a backcourse ILS approach t o runway 22 at La Guardia is outlined in t h e American Airlines Fl ight Manual carried by t h e p i l o t s of N 6101A; cross the La Guardia Range at the m i n i m u m height of 800 feet (820 above sea level) at 1hO knots; when over the center of t h e La Guardia Range s ta t ion, commence an immediate descent while maintaining l.40 knots; l eve l off a t 400 feet, the m i x h u m Electra ce i l ing f o r one mile visibil i ty, and increase power t o maintain level f l i g h t untfl t h e landing w a y is sighted or the time t o execute the missed approach procedure arrives. This is approximately one minute and 15 seconds past La QeraxHa Range. The ILS approach plate fo r runway 22 is appended to %his report.

Should t h e p i l o t s es tab l i sh visual contact with the runway a t the 4 0 0 - f O O t minimum al t i tude, they may hare t o make final direct ional changes f o r proper runway alignment, lower flap8 t o landing position, lower and turn on landing l igh ts , and descend t h e 400 feet t o t h e runway.

ANALYSIS

Testimony received by the Board indicates t ha t Captain I ) e W i t t had engaged t h e autopt lot after t h e takeoff climb from Chicago. Since it did not operate correct ly i n t h e "manual modew position, a malfunction which was written i n the a i r c r a f t log- book, t h e autopilot was engaged i n the "heading mode" position f o r the remainder of the f l i gh t , including the instrument approach.

'he only other unusual events of record during the f l i g h t and pr ior t o reach- ing New Rochelle were a dr i f t off course f r o m Amber 7 Airway before reaching the Sparkhill intersection; t he discrepancy of 30 degrees i n the first of f icer ' s RMDI; a r i g h t ta rn short of the loca l izer center l ine j u s t p r io r t o reaching N e w Rochelle; and a reported slow response by the crew t o in s tmc t ions f r o m La Quardia Approach Cantsol

Since the f l i g h t to New York was uneventful except f o r t he above mentioned incidents, t h i s Analysis will concentrate upon the f i n a l segment of the flight path. (See Approximate F l igh t Path, Appendk B.)

The weather a t La Quardia Field, t h e weather kncwn t o prevail i n t h e New Rochelle La Ouardia area, and the weather reported by the f l l g h t inmediately pre- ceding Fl ight 320, make it highly probable tha t F l igh t 320 could not have been observed from t h e ground imed ia t e ly pr ior t o t h e range s ta t ion at an a l t i t ude much above 400 feet, That this f i n a l descent had been i n i t i a t e d a t an a l t i t ude less than

-11-

t h e approved m i n i m u m of 820 feet as1 over t h e range statim i s r borne out by the observation8 of the witnesses i n t h e v i c i n i t y of the s ta t ion , A lay o r wen a skilled aeronautical witness has great difficulty in estimating accurately the height of an aircraft above the ground. atis is especially t rue when the kind and size of t h e aircraft is not known t o t he witness and familiar reference p o h t s f o r establishing r e l a t ive size and height are neither known nor discernible, It is pos- sible, howewer, to obtain a compelling impression which, while not accurate i n every detail, establishes the most signif icant facts.' In t h i s instance the Board is of the opinion t h a t the one known eyewitness t o F l i g h t 320 j u s t p r ior to its passage over the range s t a t ion actual ly saw it, t h a t it waa flying low, and was headed i n the direct ion of t h e range station. 'ihe h a d is of the opinion, however, t h a t his estimate of 100 feet i s too low, In fact, to have descended t o an a l t i t u d e below 300 feet and successfully traversed the area without col l iding with buildings o r other obstacles, many of which are about 200 f e e t i n height along the approach path leading t o runway 22, or without having attracted the at tent ion of m y other w i t - nesses, is highly improbable. approached t h e range s t a t ion at a height greater than 300 feet and probably higher than LOO feet above the ground,

It is believed, therefore, t ha t Fl ight 320 definitely

-

If that be t h e case, one must re turn t o the testimoryr presented by t he crew, physical evidence of t he wreckage, and t h e l imitat ions on the possible f l i g h t paths of Flight 320 from the range s t a t ion t o the point of impact. All a v d l a b l e evidence shows t h a t F l igh t 320 struck the water i n a very shallow descent approximately one

range s t a t ion at 900 feet and strike the water uhere it did, Flight 320 would have had t o have experienced an average rate of a t least 900 feet per-minute throughout its descent. lating t h e f i n a l approach of Fl ight 320 t o La Guardia, it w88 observed t h a t t o sta- bilize t h e ai rspeedat 135 knots, and the rate of descent a t 25'0 feet per minute, 980 - 1,200 h,p. were required.

h n u t e d t e r passing the range -station. -FurChaYrmors, the point a t which impact doccurred was only two miles from the range s ta t ion , I n order t o have passed the

During the engineering f l i g h t test of the static pressure system s h -

Operational f l i g h t t e s t s obaeroed by Board personnel were conducted on June 16, 1959, between the range s t a t ion and the crash s i t e using an American Airlines Lockheed Electra 188, N 6113, which had a gross weight of 97,192 pounds at takeoff. 63 degrees F; surface wind, northwest a t 15 knots; winds at 1,000 feet were from 300 degrees a t 16 knots; at 2,000 feet, from 300 degrees at 21 knots. 900-foot descent with a constant Grsepower of 900 and 1,200, descent rates up t o 2,000 = 2,500 feet per minute w e r e reached, with airspeed indications of 175;/195 knots observed.

Atmospheric conditions exis t ing a t t h e time were: surface temperature

In simulating a

Such indications should normally have been immediately perceptible t o the crew. If Fl ight 320 crossed the range s t a t i o n ~ a t approximately LOO feet, a rate of descent of approximately 400 feet per minute would place the a i r c r a f t at t h e approximate impact point. Under condition8 of sti l l air such a rate of descent would be canpat- ible with t h e evidence concerning the horsepower output of t h e engines dur ing descent and at the time of impact since t h e brief period during which the aircraft w a s reported t o have reached a r a t e of descent of 600400 fee t 'per minute would require 8 r a t e of

J 'lescent i n the order of 200-300 f e e t per minute during the remainder of t he descent t o the water,

As a result of this accident and i n connection with its investigation, the Board arranged extensive tests of the altimeter systems and components of the Electra.

- 12 - Tests were accomplished on the effect of a possible s t a t i c leak i n the nose wheel w e l l static eystean components; of r a i n and i c ing on t he static ports; of a large spoiler ahead of t h e static ports; and of simulated careless washing and ground splash on t h e s t a t i c system. flying through freezing water dumped fran an Air Force tanker. tests indicated ice buildup on the fuselage w a s confined t o the forward section and did not approach the area of the s t a t i c ports even when the test D e c t r a was yawed drastically. g e l and outer case areas of drum altimeters. hbjected t o these vibrations and exercised repeatedly i n a manner approximating t h e p ro f i l e of t k w Fstdl f l i g h t and over a period of more than 500 hours. No st ick- ing, lagging, o r other malfunction was noted. i n a transparent case which permitted examination with a strobe l i g h t in a vibrat ion envGo&ent S-Mlar t o that of t h e Electra instzunaent panel, measure the e f f ec t of contamination in the inlet f i l t e r screen of drum altimeters by liquids, dry-wing insects, and other contaminants, wide range of rates of climb and descont, too high during a descent a t close t o sea level, ing t he f i l t e r screen with turbo o i l .

The nectra static system was evaluated in f l i g h t by Ihe results of these

I n f l i g h t vibration measurements were obtained from the instrument Seven drum altimeters were then

I n addition, one altimeter was enclosed

Tests were conducted to

The ef fec ts were measured f o r a The greatest e r ror produced was 285 f e e t

This w a s caused by completely coat-

I n addition t o the tests arranged by the Board, tests were accomplished by Lockheed Aircraft Corporation on two graups of t en altimeters wherein they were mounted i n a t e& panel a d mer&& frm ground level t o 10,OOO f e e t m.s.1, a t an average rate of c U b and dement of 500 feet per minute. m o v e d outdoors where it was subjected t o the changes i n ambient temperature occurring over 24-hour periods

!&e second group was )

Similarly, an exhaustive review has been accomplished of all maintenance records,

Pr ior t o and since t h i s accident, several malfunctions of drum altimeters including p i l o t complaints of all operators, c iv i l and military, u t i l i z ing t h i s type altimeter. of the type installed on N 610l.A have been repxted, tions which have occurred are described b e l o w t

2he more s ignif icant malfunc-

On an American Airlines EZectra t ra in ing fl ight at Fort Worth, on February 7, 1959, one drum alt imeter reportedly stuck on three occasions; once a t 2,350 feet, and twice a t 12,320 feet, a r e a u of Standards laboratorg disclosed tha t l i n t was adhering t o the pinion teeth, remuval of which permitted the instrument t o function sa t i s fac tor i ly , seal had been broken there'oy preventing determination of the time l i n t had been in- troduced i n t o the instmment,

Inspection of the internal. mechanism a t the National

The factory

A drum al t imeter ins ta l led aa a " th i rd" alt imeter on American Airlines Electra N 6107A stuck at1 ,XO feet on an ILS approach and landing a t Detroit , Michigan, on AprU 3, 1959. ceased and t h e instrument indications became nomal. Kollsman and the National Bureau of Standards disclosed this alt imeter t o be i n sa t i s f ac to ry operating condition,

During the removal of the instnunent from t h e panel., the s t i c k h g Examination and 'E30 tests by

Of the twelve other drum-type alt imeter malfunctioning reports pr ior t o and \ since February 3, 1953, f i v e reported sticlcifig above 9,000 f ee t ; one reported stick-,, 4

ing (no altitude given); one read 630 feet a t any altitude (with the condition reported as being remedied by removing a kink i n the connecting hose); one reported lagging and sticking due t o s t icky stops (no a l t i t ude given); two reported barometric pressure knobs difficult t o turn because of loss of lubricant, but wi th no s t icking

- 13 - 1 1 - i n a l t i t u d e readings; one read 1,OOO feet off because of being ou t of cal ibrat ion; and one was reported as malfunctioning, but except fo r seri .al number and date, no information was given. &unctions waa insuf f ic ien t t o make complete evaluations.

In many instances, information supplied concerning these

Of t he drum-type altimeter malfunctions mentioned above, none of these mal- functions involved more than one of the drum-type altimeters aboard the aircraft. In a d a t i o n , examination and t e s t ing of the altimeiters irrvolved in t h i s accident failed to reveal any mechanical f a i l u r e not a t t r ibu tab le t o impact shock and i m - mersion i n salt water. indications discussed earlier i n t h i s analysis could not have been detected i n labor- a tory examination and tes t i f the a l t imetem involved had been subjected t o impact and submersion as were t h e altimeters installed on N 6 lOlA.

It should be noted that t h e f a i lu re s causing known erroneous

The Board believes that t h e destruction of the two instantaneous v e r t i c a l speed indicator in te rna l mechanisms was caused by impact and submersion of the instrument panels i n approximately 20 feet of water. I

Following the erroneous a l t i t ude indication of 8 drum al t imeter a t Detroit, Michigan, AprZl 3, 1959, mentioned above, use of the drum-type instrument as a "thirdn altimeter was discontinued by a l l air carriers operating ELxtras. t h a t time, the Board has had no opportunity t o observe o r m a k e further c r i t i c a l examination of drum altimeters i n ELectra aircraft even as a "thirdn or standby instrument. other aircraft are being monitored.

Since

However, the senrice results of the use of this type of alt imeter i n

On the I$asLis of tho available evidence, several possible equipment malfunctions and operational e r rors have been examined critically with a view to determining the most probable cause of this accident.

Dual Altimeter Failure

As far as could be detexmined, the two dnua-type alt imeters were ins ta l led i n N 610l.A at the Lackheed factory. of f l i g h t time during a l l of which the al t imeters had operated sa t i s fac tor i ly .

Electra N 610U had approximately 302 hours

According to the testimony of F i r s t Officer Hlavacek and Fl ight Engineer Cook, the alt imeter indications appeared normal throughout the approach to approximately 500 feet when the a i r c r a f t struck the water. t h a t any er ror i n t h e two drum alt imeters must have been i n the nature of a l a g r a the r than pointer sticking. indication during the approach from N e w Rochelle t o the point of impact consistent with descent contemplated i n the instrument approach procedure. they conscious of a prolonged indication of a fixed altitude. 500 feet a t the moment of h p a c t , the l a g i n the altimeters must have been approx- imately 500 feet. None of the altimeter malfunctions known t o the Board here have involved similar manifestations. L

From the i r testimony it is apparent

Both testif ied t o a gradual reduction in altimeter

A t no time were To have indicated

As required by the Civ i l A i r Regulations, t he altimeters i n s t a l l e d on the $&lot's and copi lot ' s f l i g h t instrument .panels have separate s t a t i c sources. The s t a t i c lines leading t o the instruments fiom'hormal source are completely inde- pendent. Since there ex is ts no C ~ E ~ I I T ~ O ~ element of t he instruments o r ayr of the i r re la ted s t a t i c system and sources, ?I ident ica l and simultaneous malfunction of these instnunents and associated systems of the magnitude suggested by the crew testimony would involve such an extreme mathematich. improbability t h a t t he Board is compelled t o reject it.

I

- 14 - I n re jec t ing the possibility of -dual and sinultaneous altimeter error the

Board nust, as a consequence, reject polytions of the testimony of one o r both flight crew members. injuries and t h a t they were also under great emotional stress, such questioning of t h e i r testimony has a r a t iona l basis. Under such circumstances, the Board has frequent ly found that t h e recollection, particularly of events immediately pre- ceding an accident, is very d i f f i c u l t and often erroneous. Furthermore, we are mindnil of the natural human tendency t o assume conformance with standard operating procedures t o f i l l i n the voids o r hazy areas of one's memory. On the basis of other evidence before us, t h e Board is compelled t o r e j e c t t h i s testimony t o the extent t h a t it would require dual and sjmultaneous failure of the altimeters i n the order of a SoO-foot lag.

Single U t h e t e r failure

stumbling blocks which compelled t h e Board t o abandon fu r the r consideration of a double altimeter e r ro ro mathematical probabi l i t i es of such extremely law order of itself f a c i l i t a t e s this judgment. we are m e t with so many operational imponderables as t o make rat ional izat ion impossible. So far as this accident i s concerned, any single altimeter failure must have involved t h e captain 's altimeter since it is c lear t ia t the captain was a t the controls of the aircraf't during the approach. altimeter failure occurred.

Considering tha t the f l i g h t crew members received physical

The possibiltty of a s ingle alt imeter f a i l u r e obviously avoids most of t h e

The absence of need for t he acceptance of compounded

However, i f we assume failure of F i r s t Officer Hlavacek's altimeter only,

The Board cannot conclude, however, t h a t a s ingle

Although F i r s t Offber Hlavacek had testrlffed concerning h i s observation of altimeter fndications down t o an a l t i t u d e of 600 feet, he had no recollection of a lower al t i tude indication. It wa8 h i s impression t h a t the inpact occurred shor t ly following his 600-foot observation; however, the Board believes tha t h i s subsequent judgment of this time interval. may be incorrect. While approaching an altitude of 500 feet it would have been expected tha t , in addition t o monitoring the instrument panel, Mr, Hlavacek would be scanning the approach area f o r lights and handling radio comnnmfcattuns. Considering the sparseness of l i g h t s on the approach over the East River, there could w e l l have been greater concentration or a t ten t ion than is usual since it is a l w a y s difficult a t night t o judge attitude and a l t i t u d e over t h e w a t e r y While t h e aircraft was i n instrument conditions, it is also not at all unlikely t h a t t he copilo-% w a s giving careful a t ten t ion t o the captain's e f fo r t s ta maintain the l o c a l i z e r path, especial ly In view of the apparent d i f f i c u f t i e s being experienced by t he captain i n maintaining a precise course. Although preoccupation with t h i s o r any of the several elements of a new cockpit environment could reasonably explain the failme of Mr,, Hlavacd t o follow the procedure required i n the Operations Mama with respect t o monitoring and ca l l ing out a l t i t u d e and airspeed below 600 feet, the Board bexeves it more l ikely t h a t he was ant ic ipat ing breaking out beneath the over- cast and, thereafter, having seen lights on the ground o r water, was focusing par t i - cularly on visual ident i f ica t ion of the &?port and was no longer monitoring the f l i g h t instruments,

t h e i r testimony of cross-checking altimeters. the flight c r m members is t o be regard& suf f ic ien t ly relia?ile for the purpose of

- -- 5 See the ibard ' s accident invastigation repoms on the To11min.g: 1lcrtheas.e Airlids, +.'La Giard ia Airport, New York, January Ih, 1952; Western Airlines, Sam

A t and pr ios t o reaching 600 fee t , t h e f l i g h t crew members are clear 8s t o If any portion of the testimony of

Francisco Bay, California, Apr i l 20, 1953; American Airlines, nr. Springfield, Iflssouri, March 20, a9550

this analysis, it must relate t o t h e earlier portion of t he approach. lherefore, with respect t o t h e poss ib i l i t y t h a t the captain's altimeter had failed, we are of the view that such a f a i l u r e d id not occur before reaching 600 feet. Although the Board has reviewed all available records concerning instrument fa i lure , none appear t o be of t h e nature and magnitude of that suggested here. As has already been in- dicated, no evidence of instrument f a i l u r e was discovered i n the examination of the wreckage.

The sole evidence of a malfunction of t h e captain's altimeter is Fl ight Engineer Cook's testimony. H i s observation of the captain's altimeter, after some c la r i f i ca - t i o n of its facial presentation, was 500 feet at impact. officer had called aut 600 feet. He made t h e observation in tu i t i ve ly after a momen- t a q glimpse of lights through the captain's side window which alerted him t o t h e fact t h a t they were extremely low.

To substant ia te fu r the r a single f a i l u r e on the captain's altimeter, we must assume a premature descent and discount First-Officer Hlavacek's testimony tha t he called out 900 f e e t over t h e La Guardia Range Station. '&is is necessary i n order to ra t iona l ize approximately a 300-foot per minute descent as testified t o by him.

This was after the first

The captain's altimeter was set at 29.83, 'he actual pressure a t the time of the accident was 29.75, and La Ouardia tower was report ing a se t t i ng of 29'.77. e r ro r i n se t t i ng of the captain's a l t imeter would account f o r 80 feet of erroneous

an accumulative error i n which the altimeter indicated from 110 to 125 feet higher than the actual a l t i t u d e near sea level,

W s

timeter indication, r correction must be made t6 the captain's altimeter, one can readily ra t iona l ize

Since an additional minus 30 t o 45 feet of errar due t o static

A premature descent is substantiated by t h e eyewitnesses t o F l igh t 320 just p r io r t o and after i ts passage over t he La Quardia Range Stationo As stated earlier, t he Board believes Fl ight 320 approached the range s t a t i o n a t a height greater than XK) feet and probably not much higher than 400 feet above the ground because of the prevailing cei l ing a t tho time.

Misreadinn t h e Altimeter

Because of t h e novel presentation components of t h e altideter, serious COA- s iderat ion has been given t h e poss ib i l i t y t h a t the p i l o t misread t h e a l t i t u d e indi- cat ion and thereby permitted or caused the a i r c r a f t t o deviate v e r t i c a l l y f'rm t he desired f l i g h t path. While some incidents have been reported i n which a p i l o t had misread t h e 1,OOO-foot scale on the small dnun, no such er ror could conceivably be involved here. pointer t he indications and appearance of which are, far all prac t ica l purposes, i den t i ca l t o those used by the crew i n other aircraft types and t h e interpretat ion of which calls f o r no new o r d i f fe ren t evaluations on the part of t h e p i lo t .

The a l t i t u d e presentation belov 1,000 feet is accomplished by a

The reversed sensing of the alt imeter s e t t i ng numerals has already been mentioned,, While an erroneous se t t i ng might r e s u l t from this condition, the possible order of error would be very small indesd. Unlike the primary inst ru- en t f l i g h t reference which is frequently "generalized" by appraxhate positions

p o h t e r s o r indicators, t h e a l t imeter s e t t i ng scale must be read i n order to permit any substantial correction t o be mde. posit ions which were found i n t h e a l t imeters instdl iod in t h i s airplane are very reliable indications .of t h e se t t ings exis t ing at the time of the accident.

Furthemore, t h e a l t imeter se t t ing

'he

Board does not beUWe t h a t t h e 80-foot error resul t ing *om the setting of the captain's instrument is chargeable t o misreading of the instrumento

ch8 other pecul iar i ty of t h i s instrument, however, has raised some question as t o suscep t ib i l i t y of misinterpretation. face a cutout is provided through which may be seen t h e d m which indicatea 1,000- foot levels. angular shaped index against which the 1,000-foot cal ibrat ions are read. In a dark- ened cockpit, t he index whioh appears on the left side of t he drum assembly cutout has a t times been mistaken f o r t he s m a l l 1,0001foot pointer which is installed on the older altimeters. Such an error would leave t h e impression t h a t a small hand was indicating an a l t i t u d e of 2,500 f e e t , t i o n of the company prior t o t h e accident and it had been agreed tha t t he left index should be removed i n order to prevent such a confusion; one of t h e company's f leet of six Illectras had had t h i s index removed at t h e time of the accidant, The alti- meters i n s t a l l e d i n the aircraft all contained indices on both sides of the cutout.

On t h e r i g h t side of t h e instrument

On both sides of this cutout there has been pr inted a luxminous tri-

' h i s fact had been brought to t h e atten-

The Board is of the opinion that confusion is also possible i n ndstaking t he r i g h t index f o r the 1OO-foot painter. of the dis t inct iveness of shape uf the 1,000-foot a l t i t ude index as compared with the 100-foot pointer, these dis t inct ions lose most of t h e i r significance at n igh t , especial ly G6ere-hurried references t o fl ight instrunrents are required in c r i t i c a l flight situ&tions.- If, i n - a ' k r r i e d glance, t he r i g h t index were t o be mistaken for t h e l a r g e 100-foot pointer, the p i l o t would have the impression of being at 250 feet when, i n fact, t h e &ireraft might be considerably M o w this al t i tude.

Although this may appear remote because'

As a part of t h e mectra training program, the company gave special a t ten t ion t o t h e need f 6 r t r a i n i n g i n t h e Bend* Fl ight Director System which was i n s t a l l ed i n the E3ectTa- and was otherwise new t o the line p i lo t s , which t h e captain received approxima';ely f ive hours of i n i t i a l t r a i n i n g on the b n - d i x Fl ight Mrec tor System had imtalled t h e conventional three-pointer altimeter and not the drum-type alt imeter which was actual ly in s t a l l ed in t h e Electra.

The ground t r a ine r i n

Misreading the Vertical Speed Indicator

The instantaneous v e r t i c a l speed indicator i n s t a l l ed i n the Electra does not possess the lag t yp ica l of older instruments which rely solely upon a calibrated flow from the dlaphragm fo r the i n i t i a l indication of climb o r descent. In t h i s regard it can be s t a t ed t h a t this type v e r t i c a l speed indicator possesses character- ist ics which are definitely superior t o those of older types. spect, however, the difference i n presentation must be regarded as s igni f icant so far as t h i s accident i s concerned. This instrument ins ta l led i n the Electra is calibrated i n such a manner t h a t a given displacement of t h e needle represents a rate of climb or descent almost three times as great as t h a t shown on fonner deaigns. For instance, were the n e d e of the .o laer instrument displaced 90 degrees downward --_--- from its normally horizontal position, it would signify a rate of descent of approot- h t e l y 7$0 feet per minute. This sme r e l a t ive posit ion i n the case of the-Electra instrument would signify a rate of descent of apprcudmately 2,300 feet per minute.

\ I n t h i a connection, it should be understood t h a t a praf ic ient instrument

p i l o t typically accomplishes m o m t h a n 1GO v i s u d fixations per ninute wnile flyingv . so l e ly by instruments during a maneuver such a3 an i n s l m m n s approach. f ixa t ion upon a f l i g h t instrument for the purpose of es tabl ishing a part icular con- dition of f l i g h t such as airspeed, a l t i tude , o r rate of descent is generally a & f r ac t ion of one second. For t h e experienced p i lo t , therefore, it is common t o rely

In at l e a s t one re-

A n y one

- 17 - upon approximate pointer posit ion rather than C O n S C i O U S b to . read t h e numerical indications associated with each pointer position. heightened a t night when precise reading of instruments is more d i f f i c u l t even with optbum instrument l igh t ing , wifh limited -sure t o t h i s par t icular instrument mighC be led t o accept an ex- cessive rate of descent because of a general appearance of instrnment indication being within a range normal f o r an instrument approach when using the older instru- ment.

Such a tendency is, of course,

Accordingly, there is a strong suggestion tha t a p i l o t

A camputation of t he times reported over New Rochelle and the La Guardia Range Station indicates t h a t the gramd speed of Flight 320 on t h e approach be= tween these fixes waa approxhately 129 knots, Over New Rochelle and the La Chlardia Range Stat ion by t he five f l i g h t s preceding Fl ight 320, and an analysis of t h e winds aloft reports a t Idlewild Internat ional Airport and surrounding areas taken at 1900, Febnxary 3, and 0100, February 4, indicates t h a t Fl ight 320 would be m a k i n g i t s approach i n t o a mean wind of approx- imately 25 knots from about 210 degrees, Rochelle and t h e La Ouardia Range Stat ion appears, therefore, t o have'been i n the order of 150 knots. t h e f l i g h t crew were using, a rate of descent higher than t h a t necessary fo r this portion of the approach procedure appears t o be likely,

A computation of t h e times reported

The indicated airspeed between New

A t t h i s indicated airspeed and at t h e power settings which

According t o t h e testimony of the f l i g h t crew, t h e aircraft passed over the The procedure cal led f o r t he f l i g h t to cross Rochelle marker a t 1,500 feet,

La Gvardia Range Station approximately L.8 miles southwest at 800 feet, A t

Since t h e f l i g h t had approximately 700 140 knots indicated airspeed, thYs distance would, i n B no-wind condition, require approximately 2:O3 minutes t o traverse, feet to descend between these two fixes, 8 ra te of descent in t h e order of 350 feet per minute would have sufficed, If the p i l o t at New Rochelle were t o adjust the attrltude so as t o obtain an apparent 350 feet per minute, based upon h is experience with the older v e r t i c a l speed indicators, he would have realized between 700 and 1,000 feet per minute, The r e su l t of an excessive rate of descent w d d be for the airspeed t o increase, higher than the a0 hots, t o which the crew t e s t i f i e d o

We regard it s igni f icant t h a t t he ground t r a ine r i n which t h e captain received initial t ra in ing on the Ben- F l igh t Mrec tor System had in s t a l l ed t h e conventional v e r t i c a l speed indicator and not the instrument which was actual ly in s t a l l ed in t he Electra.

2he poss ib i l i ty of misreading either t h e altimeter o r the v e r t i c a l speed indi- cator could hardly of i t s e l f satisfy the Board's search f o r a probable cause of the accident, moreover, the copilot has full f a c i l i t y for monitoring and cross-checking through a completely independent f l i g h t instrument panel, Presumably, misinterpretation of one condition of f l i g h t should not normally result i n gross displacement of aircraft position,

e fo r a dangerous drift from a desired f l i g h t path when a cer ta in combination of umstances ex is t s , par t icu lar ly when tha t environment includes any insidious o r eading assurances of a safe f l i g h t condition.

The evidence of record shows t h a t the airspeed was i n f a a t

!€here exist far toa m a n y other sources of cross-check f o r t h e p i lo t ;

However, preoccupation with any one other cockpit problem may set the

I (See Appendix C.)

- 18.- . .

The Eclipse-Pioneer autopilot , model PE20E, used by American Airlines on its ELectra airplanes is designed t o permit cmple t e ly automatic control of the airplane from i n i t i a l climb through an IIS approach. Autmatic navigation and approach, and automatic a l t i t u d e and pitch trim control are incorporated i n the system, gl ide path is su i tab ly paired with a loca l izer courseo Since no g l ide path is available, an automatic approach could not be m a d e on the backcourse of t h e La Guardia ILS,

Tbstimony of the first o f f i ce r and f l i g h t engineer indicates t h a t Captain D e W i t t was making a.nheading modeA autopilot approach and t h a t the autopilot was still engaged at impact, mediate systan t o operate t h e f l i g h t controls instead of operating them directly through the control wheel and rudder pedals in the conventional manner, plane is steered by select ing a desired heading on the course deviation indicator; t h e autopi lot then d i rec ts the airplane t o t h i s heading, using t h i a procedure during the en t i r e f l i g h t after t h e takeoff climb. t o testimony, he w a s actuating the pitch trim wheel, which is mounted i n the auto- p i l o t control ler on the pedestal t o his r igh t and s l i g h t l y af t , with his r igh t hand and was leaning forward in his seat to reach around t he control wheel with his left hand t o ro t a t e t h e e 1 m m w ? $as& .bQ iupmto Since no g l ide slope is avail- able, proper a l t i t ude mer fixes must be checked so le ly by reference t o t h e alt imeter

l imitat ions as t o the type of approach f o r which t h e autopi lot may be used; nor does it establish any minimum a l t i t u d e l imitat ions f o r use of the autopilot. While it is recognized t h a t the autopi lot system ins t a l l ed i n the Electra is capable of cmple t e automatic control of descent path and direct ion i n an Us approach, t h e ELectra Air- plane Operating Manual. specif ies t h a t the autopi lot must be off before leaving a holding point f o r f i n a l approach,

An automatic ILS approach u t i l i z ing the PB-20E is possihle only where a

I n t h i s method, t he p i l o t uses the autopi lot as an inter-

The air-

Captain D e W i t t had been According

%e FAA-approved portion of the Electra Airplane Operating Manual contains no

Although Captain D e W i t t had made many ac tua l instrument approaches t o La b a r d i a Airport i n other than Electra a i r c ra f t , and had made several simulated instrument approaches in the ELectra, the Board could f i n d no instance where he had made a previous backcourse IIS approach t o L a Quardia Airport i n an Electra under actual instrument conditions, Records were not available t o determine how much previous experience Captain D e W i t t had i n making simulated o r actual instru- ment approaches i n the EZectra using t h e "heading mode" autopi lot setting.

Most of t he wreckage was found within a 200-foot radius c i r c l e , the center of which was located approximately 4,891 f e e t short of the threshold and 610 feet to t h e r igh t of t h e extended centerline of runway 22. horizon director indicator and course deviauon indicator wauld indicate ful l -scale deflections if any a i r c r a f t were appmximately 300 feet to the r igh t of the loca l izer center l ine and approximately 5,000 f e e t from the localizer shack, The lateral dis- placement of this aircraft from t h e loca l izer courge is excessive and indicates t h a t t h e p i l o t might not have been maintaining proper alignment with t h e localiser course during the l a t t e r portion ci' t he approach.

It was determined t h a t the

'

The captain's and first o f f i ce r ' s RMDI's, when removed from the water, read 205 degrees and 219 degrees, respectively. two RMDI's reasonably agree with the instrument approach heading t o be flown, neither

Although t h e heading indications of the

- 19 - reading is necessarily t h a t of the aircraft heading a t impact. impact forces and the exact ins tan t a t which each of the compass systems ceased operation are unknown. t o be i n e r ro r and the extent t o which this malfunction influenced the f i n a l reading of that instmment is not ham,

The ef fec ts of

In addition, t h e first off icer ' s RMDI was previously found

Consideration was given t o the poss ib i l i ty t h a t the a i r c r a f t d r i f t e d a f t e r i n i t i a l impact. ing and following the accident were such as t o have a negligible effect so far as the wreckage location is cgncsmed. have been i n the direct ion which would bring it closer t o the loca l izer centerline. The Nard believes the-a&rcraft components of substant ia l mass such as the engines, aank immediately and is of the vieu t h a t drift after i n i t i a l impact w a s negligible.

It was determined t h a t the tides and currents i n the channel dur-

Had qf dr i f t i ng of wreckage occurred, it would

Captain D e W i t t was using t h e Ifs l oca l i ze r for direction i n conjunction with t h e OF'S t o determine precisely the a i r c ra f t ' s posit ion over the navigational fixes. Ris No,, 1 ADF was tuned t o the La Quardia compass locator; to the La Guardia Range. t he RMDI, the selector on t h i s instrument must be placed i n the ADF position.

the No, 2 ADF was tuned In order f o r ADF information to be displayed visually on

Investigation disclosed t h e selector switch f o r the captain's No, 1 ADF needle

Under these conditions the single needle would be displaying the position of was selected t o t h e ADF position; however, t he No, 2 se lec tor was i n the VOR posi- t ion.

La Chardia middle marker which i s southwest of the a i rpor t and, therefore, would pproximately s t r a igh t ahead of t h e f l i g h t throughout t he f i n a l approach t o the

moment of impact; however, t he No. 2 or double needle would be inactive, eliminating its use i n displaying the posit ion of the La Guardia Range, difficulty i n receiving the range stat ion, although s t a t i o n passage was observed by the first of f icer on his RMDI. above t h e La Guardia range frequency and i n t h e loop position, t h i s suggesting a possible manipulation of the ADF controls t o confim s t a t ion passage,

Testimony a lso indicated

Be No, 2 ADF control se t t ings were t en kilocycles

Operations Specifications issued t o American Airlines on January 23, 1959, require t h a t the cei l ing and v i s i b i l i t y landing minimums prescribed i n the Operations Specifications be increased by 100-foot ce i l ing and one-half mile v i s i h i l i t y whenever the captain i n scheduled operation has not served for 100 hours as pilot-in-c&and on t h e equipment, or unti l such time as t h e captain is ce r t i f i ed by h i s Regional &perintendent of Flying as qualified t o operate a t the landing mininnunS prescribed. If these r e s t r i c t ions are t o seme any purpose other than t o give t h e appearance of a conservative f l i g h t operations policy, the B o d questions t he wisdan of t h e company in exempting Captain D e W i t t when he had but 12:32 hours of f ly ing the ELectra i n scheduled operations. This occurred nine days before t h e accident.

The Board has recommended t h a t me Ad_mini&r_ator r&.ew exist ing FAA policy t o determine whether the waiver provision contained i n the Operations Specifications should be deleted..

Inadequate Operational Technique

Another poss ib i l i ty of accident causation is concerned with adequacy of operational techniques,,

Approaching New Rochelle and f o r the remainder of t h e instrument approach, the aircraft was flown on autopilot i n t h e heading mode and wi th the flaps i n

- 20 - approach position, at 1,500 feet and the p i l o t established a rate of descent which he believed t o be i n the order of 350 feet per minute. Because of the d i f fe ren t cal ibrat ion of the ve r t i ca l speed indicator as compared with the instruments used by the captain during almost all of h is previous 29,000 f ly ing hours, t h e actual rate of descent w a s be- tween 900 t o 1,000 f e e t per minute u n t i l checked by Captain Ddditt, The captain's altimeter indicated an a l t i t ude approximately 125' feet higher than the actual &ti- tude, Since the captain w a s u t i l i z i n g the autopilot, h i s corrections of a l t i t ude and direct ion were samewhat slower than would normally be expected i n a manual approach. Because of the excessive rate of descent, the a i r c r a f t descended below the minimum altitude prescribea f o r s t a t ion passage, When crossing the La Guardia Range Station, t he captain's alt imeter indicated approximately 600 feet, which was s l igh t ly l e s s than 500 feet above sea level,,

The landing gear was extended while passing over New Rocelle

When passing the range s ta t ion, the p i l o t lowered the nose of the aircraft to establ ish a rate of descent of approximately 250 feet per minute, inasmuch as this rate of descent, i f held f o r 60 seconds, would bring him t o an indicated a l t i t ude from which a visual landing may eas i ly have been made t o runway 22, range stat ion, he established a descent of from 600-800 f e e t per minute, Approxi- mately 20 seconds a f t e r passing the La &ardia Rarge Station the a i r c r a f t passed through an indicated 400-foot a l t i t ude which w a s s l i gh t ly l e s s than 300 feet above t h e water, A t this time t h e f l i g h t engineer and first of f icer observed l i g h t s below the overcasto I n accordance w i t h American Airlines' Operations Specifications, Fl ight 320 could descend t o a m i n b of 350 f e e t indicated al t i tude. Approximately 1 2 5 f ee t ! of cal ibrat ion and se t t ing e r ror i n t h e captain's drum alt imeter would mean the air- craft actual ly could have descended t o 225 fee t , Brief visual check on the instrument panel indicated only a very s l igh t descent and it is possible that , expecting t o f ind t h e 100-foot pointer smewhere i n the v i c in i ty of 250 t o 300 feet, he mistakenly accepted t h e indic,es on e i the r s ide of t h e drum when, i n fact , the 100-foot pointer was already approaching approximately an indicated 125 f ee t , f l i g h t a l t i t ude with the l imited v isua l reference available over sparsely l i g h t e areas such as the Rikers n l a n d Channel at night, is not an unknown phenomenon.^ Furthermore, because of a dike located between t h e end of runway 22 and t h e water of the channel, the threshold l i g h t s which are slanted a t between three and f i v e degrees would not be observed by the crew of Fl ight 320 unless t h e a i r c r a f t had been a t or above the following elevations when a t designated distances from runway 22:

On passing the

The i l l u s ion of a safe

?

Distance

l/lr mils 1/2 mile 3/4 mile 1 mile

1=1/4 miles 1 4 2 miles L3/4 miles

2 miles

Three-degree Slant

79 feet 159 feet 240 feet 338 feet 400 feet 478 feet 557 feet 637 feet

Five-degreeSlant

132 feet 265 feet 400 f e e t 530 feet 665 f e e t 798 feet 929 feet

1,062 feet

Under these circumstances the descent continued f o r the few seconds remaining u n t i l impact was made by t he landing gear and r i g h t wing w i t h t h e water.

6J See footnote 5 , page 4.

- 21 The reconstruction of the f l i g h t path accomplished i n the foregoing para-

graphs might well be adjusted f o r some addilfonal altimeter error not previously indicated o r disclosed during the investigation. However, we are of t h e view t h a t if such an e r ro r did in f a c t exist it need not have been of great magnitude t o per- nit ra t ional izat ion of the fgctors involved.

CONCLUSIONS

The Board concludes there is no one fac tor so outstanding as t o be considered On the contrary, the Board has found that as the probable cause of t h i s accident.

the accident was an accumulation of several fac tors or errors, which, together, cm- prised the safe ty of the f l i g h t ,

?he Board believes, after exhaustive and detai led investigation, t h a t F l igh t 320 f l e w at an average ground speed of 130 knots between New Rochelle and the La Ouardia Range Station, aircraft t h a t preceded Fl ight 320, the Board has determined its indicated airspeed oyer t h i s area t o be approximately 150 knots. The a i r c r a f t passed over La Quardia Range Stat ion at a l o w al t i tude, possibly as l o w as 300 fee t , but probably not higher than 500 feet. The crew had l imited visual reference following t h e range passage; t he f irst of f icer and f l i g h t engineer observed l i g h t s j u s t p r ior t o impact. t h e instrument approach, the captain's altimeter was indicating at l e a s t 80 f ee t , and possibly as much as 125 feet above the a l t i t ude a t shich the a i r c r a f t w a s flying owing

Using winds a l o f t data and time-over-fix data received from

During

a l ibra t ion and se t t i ng errors.

Jus t -pr ior t o impact, t h e a i r c r a f t was i n a shallow descent, i n approach con- .f iguration except f o r landing f l aps and landing l i g h t extension, and was maintaining approximately 130 knots groundspeed. p i l o t "heading mode" during which he was controll ing a l t i t ude ky manipulating the p i tch trim wheel wi th his r i g h t hand and controll ing direct ion by ro ta t ing t h e C D I cursor with his l e f t hand. Impact occurred within seconds after t h e crew received and acknowledged clearance t o land. The testimony of the first of f icer and f l i g h t engineer concerning the simultaneous misindication of both drum altimeters could not be substantiated by t h e evidence of record. tain's altimeter was examined. evidence available t o substant ia te this.

Captain D e W i t t was f lying the aircraft on auto-

The poss ib i l i ty of f a i l u r e of the cap- However, the Board believes there is insuff ic ient

The Board believes t h a t even though the accident probably resulted from the captain's neglect of certain essent ia l instrument references, it could have been prevented had the first of f icer followed prescribed operating procedures, and been fully alert and a t ten t ive t o a l l his cockpit dut ies throughout the approach.

As a result of t h i s accident, the Federal Aviation Agency, on February 8, 1959, Upon t h e in s t a l l a t ion of the as a "precautionary measure," raised Electra minimums.

conventional throe-pointer type sensi t ive altimeters, the r e s t r i c t ions were l i f t ed .

During this investigation considerable.testimony was presented concerning American Airlines ' procedures and techniques employed i n the operation of autopilots. The Federal Aviation Agency testif ied t h a t it had not issued any policy directives ir $I respect t o the use of autopilots i n the various possible types of instrument akproaches cj for an air carr ier .

While the Board considers t ha t f u l l y automatic front course ILS approaches using an autopilot coupler may be basical ly sound, it is the Board's opinion t h a t

- 22 - autopi lot approach criteria and l imitat ions t o all air carriers should be established, taking i n t o account the par t icu lar autopilot used, the aircraft involved, and t h e approach f a c i l i t i e s ut i l ized. recommended t o the FAA t ha t it init iate a study of air carrier pol ic ies , pro- bedures, and techniques fo r employing an autopi lot f o r instrument approaches and take whatever action appears appropriate.

Accordingly, the Board has

Service Testing of New IQuipment

Although, as indicated in previous sect ions of this report, the Board does not believe tha t altimeter malfunctioning was a major factor i n this accident, it is convinced t h a t the searching investigation of the altimeters as a result of this accident has disclosed the need f o r changes i n t h e procedures used t o approve such items of equipment and instrumentation.

Units such as t he Xollsman drum alt imeter, t he Eclipse-Pioneer Fl ight Director Systsm, and the PB.20 autopilot are approved f o r c i v l l use by the Federal Aviation Agency under the Technical Standard Order System. product under t h i s system, a manufacturer certif ies t o the FAA tha t he has complied with all of t he specifications and has conducted all of t h e tests contained i n the appropriate E O . This ce r t i f i ca t ion by t h e manufacturer const i tutes FAA approval, and the manufacturer is free to market his product and a prospective purchaser, such as an a i r l i ne , is then able t o install. t he item i n an a i r c r a f t without fur ther sub- s t a n t h ~ t i o n of the product. Typically, FAA's "SO program does not require inservice,\ s u i t a b i l i t y t e s t ing of items t h a t are approved, nor does it incorporate spec i f ic f

qual i ty control standards. Furthermore, evidence developed during t h e Board's imres- t i ga t ion and public hearing on this accident indicated t h a t FAA had no overal l defin- i t ive program for monitoring routine service difficult ies on !EO items,

I n obtaining approval f o r his

~

Service t e s t i n g of novel designs before f lee twise- ins ta l la t ion is authorized would be very instrumental i n uncuvering design deficiencies i n a product, incorporation of spec i f ic q u a l i t y control standards i n the TSO and/or direct sur- vei l lance of the manufacturer's qual i ty control organization by FAA inspectors w u l d insure only high-quality products gett ing into service, of minor d i f f i cu l ty reports on newer TSO items would detect trends before a serious f a i l u r e o r malfunctioning occurred.

The

Closer monitoring by the FAA

These Board views have been conveyed t o t h e FAA.

The Board also believes t h a t the ca r r i e r has definite obligations i n t h i s area. In vim of the novel presentation of t h e dnun altimeters, t h e Board f inds it diffi- cu l t to understand why American did not at least incorporate t h i s instrument i n the Electra cockpit t ra iner used by the f l i g h t crew during their Electra training. Al- though this would not have been aa beneficial as a more extensive preservice tes t evaluation of this instrument, it muld a t least have provided the flight crews with some experience on t h i s important sa fe ty instrument before they used it i n actual scheduled service. have been a desirable instrument to lncorporate i n the cockpit t ra iner . added emphasis should have been placed on the difference between these new instru- ments and the older types during the crew t ra in ing program u n t i l such time as it was evident t h a t t h e various c ram were experiencing no unusual amount of difficulty in

i effect ing t r ans i t i on t o t h e newer types.

Similarly, the new instantaneous v e r t i c a l speed indicator would In addition,

- 23 - A & r a f t Simulator

The Board notes t h a t the ca r r i e r introduced an a i r c r a f t containing the m a n y novel systems and character is t ics of the Electra without having previously estab- l ished a comprehensive aircraft simulator program. an approved Electra simulator, Cer ta in ly there is l i t t l e question t h a t t h e present state of the art and the benefi ts t o be derived from the use of simulators indicate the desirability of u t i l i z i n g simulators pr ior t o the introduction of the a i rc raf t i n t o air carrier - - - senrice,

Whether o r not aqy of the m a n y fac tors which have been discussed in t h i s report are of themselves cri t ically related t o this accident, we believe that t h e i r accurm- l a t ive -e f f ec t is s igni f icant - so signif icant i n fact, t h a t the extent t o which they appear t o compromise the safety of ELectra operations must be seriously regarded, W e are a lso of t h e view t h a t almost all adverse operational aspects of new and substan- t i a l l y d i f fe ren t equipment, systems, and procedures, could have been avoided through more comprehensive t ra in ing i n an aircraft simulator,

"he ca r r i e r has not yet procured

The Board has on previous occasions indicated its concern over the need f o r vigorous and comprehensive aircraft simulator program8 i n air carrier operationso The introduction of the ELectra has increased our concern i n t h i s respect. ingly, we have recommended t h a t the Federal Aviation Agency give b d i a t e considera- t i o n t o t h e adoption of a requirement that any air ca r r i e r planning t o introduco in to service an a i rc raf t type containing equipnent, systems, or character is t ics s ign i f icant ly P p f e r e n t from those of predecessor a i r c ra f t , s h a l l be required t o i n s t i t u t e an approved , . e c r a f t simulator program the completion of which s h a l l be required before any p i l o t may be assigned as pilot-in-command i n a i r transportation,

Accord-

F l igh t Recorder

I n 1957 t h e C i v i l Aeronautics Board adopted an amendment t o t h e C i v i l Air Regulations which required the in s t a l l a t ion of a ' d m i c e on cer ta in aircraft used i n air transportation f o r the purpose of recording continuously during f l i g h t , time, airspeed, a l t i tude, ve r t i ca l acceleration, and heading. considerable opposition i n the aviat ion industry and serious consideration was given by the Board t o t h e question whether t he potent ia l value of t h i s device justified the cost of procurement, ins ta l la t ion , and maintenance, 'he Board finally concluded tha t only the l a r g e r turbine-engine a i r c r a f t intended for operation i n completely new en- vironments would j u s t i f y t h e expense of providing f l i g h t recmders, aircraft types the Board r e l i ed upon a simple c r i t e r ion - such recorders would be re- quired i n a i r c r a f t ce r t i f i ca t ed f o r f l i g h t above 25,000 feet. is capable of f l i g h t above 25,000 feet, t he carrier chose t o request cer t i f ica t ion below 25,000 feet under which l imitat ion it is unnecessary to all f l i g h t recorders. The probabili ty t h a t t h i s would be done was known t o the Board a t the time t h e regula- t i o n was written, However, the Board concluded tha t t h e regulation, then promulgated, represented t h e most demanding requirement which could be j u s t i f i e d on the basis of t he then exis t ing state of the art,

Clearly, a f l igh t recorder i n t h i s aircraft would have enabled us t o ident i fy t h e causal factors involved i n t h i s accident x i t h far greater precision than is now r(clsihle. The Board is of t h e view t h a t t h e qual i ty of f l i g h t recording systems which t W available t o t h e industry warrants the conclusion t h a t no large a i r c r a f t intr'oduced in to air ca r r i e r service should be without 8 recorder. Accordingly, the Board is rec- &ending t h a t the FAA ini t ia te act ion to amend the appropriate regulations t o require t h a t a l l lar e turbineengine aircraft used i n air transportation be equipped with

l h i s requirement met wi th

Ib define such

Although the Electra

f l i g h t recor % ers ,

- 2l4 - PROBABLE CAUSE

'Ihe Board determines the probable cause of t h i s accident was premature descent below landing minimums which was t h e result of preoccupation of t h e crew on particu- lar aspects of the a i r c r a f t and its environment t o t h e neglect of essent ia l f l i g h t instrument references f o r a t t i t ude and height above the approach surface.

Contributing fac tors were:

1.

20

3.

L. 50

60

Limited experience of t he crew with the aircraft type;

Faulty approach technique i n which the autopilot was used i n the heading mode t o o r almost t o t h e surface;

Erroneous se t t ing of the captain's altimeter;

Marginal. weather i n the approach area)

Possible misinterpretation of altimeter and rate of descent indicator; and

Sensory i l l u s ion with respect to height and a t t i t ude resul t ing from v i s u a l reference t o t h e few l i g h t s exis t ing i n the approach area.

BY THE CIVIL AERONAUTICS alARD:

/s/ JAMES R, WRFEE Chairman

/s/ CHAN GURNEY Vice Chairman

/s/ G. JOSEPH MINETTI Member

/s/ W d T N E Y GILLILLAND l Member

/s/ ALAN S , BOYD Member

1 Investigation and Hearing

The Civi l Aeronautics Board w a s not i f ied of the accident on February 4, 1959, soon after occurrence. with the provisions of Tit le VI1 of the Federal Aviation Act of 1958. hearing was ordered by the Board and w a s held i n New York, New York, March 18, 1959.

An investigation w a s immediately in i t i a t ed i n accordance A public

Air Carrier

American Airlines, Inc., is a Delaware corporation and maintains its principal offices i n New York, New York. public convenience and necessity issued by the Civil Aeronautics Board to engage i n the transportation of persons, property, and mail. carrier operating certif icate issued by t h e Federal Aviation Agency, (formerly Civi l Aeronautics Administration) .

The corporation holds a current certif icate of

It also possesses a va l id air

Fl ight Personnel

Captain Albert Hunt D e W i t t , age 59, w a s employed by American Airlines on June 6, 1929, He held a currently effective airman certificate with a i r l i n e

,'transport and a l l other appropriate ratings. He had a t o t a l f ly ing time of -28,135 hours, of which 48:13 were in Lockheed Electra aircraf t . rily passed h i s l a s t FAA (formerly CAA).physical examination October 16, 1958. H i s l a s t semi-annual proficiency check was given by one of the company's check p i l o t s December 16, 1958.

H e sa t isfacto-

F i r s t Officer Frank Schopen Hlavacek, age 33, was employed by the company on January 29, 1951. t r a n s p o r t ra t ing and Convair 240, 340, and U O type ratings. 10,192 flying hours, of which 36:35 were i n Electra aircraft. physical examination w a s s a t i s f ac to r i ly passed June 7, 1958.

H e held a currently effect ive airman ce r t i f i ca t e w i t h a i r l i n e He had a total of

H i s last FAA

Flight Engineer Warren Edward Cook, age 36, was employed by the company July 28, 1948. He had a total of 8,700 f lying hours, of which 81:29 were in Electra aircraft. H i s last physical examination w a s satisfactorily completed November 7, 1958.

He held a current airman certificate with f l i g h t engineer rating.

' Stewardess Mae Markidis, age 22, was employed by the cornparor May 7, 1957. Stewardess Joan Zeller, &e 21, w a s employed by the company on July 29, 1958.

The Aircraft

Electra Aircraft, model L-188, N 6101A, w a s manufactured November 27, 1958, by hckheed Aircraft Corporation. 5OlDl3 engines . manufactured by Aero Products, Allison Division, Germral Motors Corporation,

The aircraft w a s equipped with four Allison The four propellers , model ~ 6 4 4 1 ~ ~ 4 0 6 , blades 6503368, were

1-6-59 AP P END I X "A"

TIME & MIM RATE OF DESCENT H lo pullout if grouiid coiitact is not established at authorized niim

1 G A Its &

ADF BACK CRS

A P C H

TO RNY 22

Kts Min SeC FPN 120 3-50 130 3.34

New York

I

Wind NNW N NNE NE . ENE E ESE 22 Magnetic 349" 12" 34" 57" 79" 102" 124"

Velocity 0-14 0.9 0-8.7 0.8.7 0.12 0-18 0-26

I PROCEDURE UTI~IZING BACK COURSE ILS WITHOUT GLIDE SLOPE I

IRadar vectors may be substituted for above transitions]

TAILWINDS GIVING AN APPROXIMATE 8.7 KNOT TAILWIND LANDING COMPONENT l R U N w A y I

1ANGES: Fqcys, Mims

FLIGHT MANUAL AMERICAN AIRLINE

Altitude 20'asl H 388 RWCiFk. LCZR 109.9 I LGAk2-r: Tower 118.7 Gnd Ctl 121.7' Apch Ctl 119.9 VOT 108.4

All altitudes ore above field level v n l e u orherw re mdicoted

Authorized as: REGULAR PRs%lONAL for ALTERNATE Washinaton

CEILING AND VISIBILITY MINIMUMS I RNWY I SVC I CONVAiR IELECTRA,DC6 s.7'

')ALTERNATE MISSED APPR0ACH:i with ARTC approval 1. Make a climbing left turn to 1500'asl return to

RWC H or 2. if unable to proceed from RWC H with 3 li visibility and clear of all clouds, make a climbing right turn to 1500'asl, and return to RWC H holding pattern.

For Airport Map see ILS Apch to Rnwy 4

OPERATIONS SPECIFICATIONS - AIRPORT

APPENDIX "C"

CONVENTIONAL THREE POINTER TYPE SENSITIVE ALTIMETER

RATE OF CLIMB INDICATOR INSTANTANEOUS VERTICAL SPEED INDICATOR

!