NOTICTBIS - PDF document

1 II ._.._ _-.----._ _ _._ .._
II ._.._ _-.----._ _ _._ .._ -- . . : .:. NOTICTBIS DOCUM.ENT HAS BEEN REPRODUCEDFROM THE BEST COPY FURNISHED US BY SPONSORING AGEN,CY. -4LTHOUGH IT IS RECOGNIZED THA.T CEkT-AIN. PORTIONSARE ILLEGIBLE,IT IS BEING RELEASED IN THE JNTEREST. OF MAII.ING.,4VAIL,A - AS ‘ TNFORMATION. AS : . .. ,. . ’ . . : ‘ . . . . . . . 1. ; _ . . . : _. _, . :. :, : . *:, : . . .- . : . :- -. : L . . N310EA . 29,1972 .._.. _.,. - . . . _. -: : AIRCRAFT D.C.. 20591 , . . TECHNICAL REPORT STANDARD TITLE PAGE Report No.‘ Accession No. 3.Recizi.yn: -, .-, . , Cat$log No. ZJ 2-i; Title and SubtitleAircraft Accident ReportEastern Air Lines, Inc. S.Report DateJune 14, 1973 L:lOll, N31QEA 972 Organization Code Author(s) Organization . - Report No. . Performing Organization Name and Address lO.Work Unit No. National Transportation Safety Board - Bureau of Aviation Safety1018-CII .Contract or Grant No.Washington, D. C. 20591 ’ of Report andPeriod Covered 12.Sponsoring Agency Name and Address ! Aircraft Accident Report December 29, 1972 NATIONAL TRANSPORTATION SAFETY BOARD ; Washington, D. C. 20591 14.Sponsoring Agency Code 15.Supplementary Notes I This report contains aviation Safety Recommendation A-73-46. 16.Abstract An Eastern Air Lines Lockheed L-1011 crashed at 2342 easternstandard time, December 29, 1972, 18.7miles west-northwest. of Miami Inter’national Airport, Miami

2 , Florida. The aircraft was destroyed. O
, Florida. The aircraft was destroyed. Of the 163passengers and 13 crew-members aboard,94 passengers and 5 crewmembers re-, ceived fatal injuries.Two survivors died later as a result of their injuries. . Following a missed approach because of a suspected nose gear malfunction,the aircraft climbed to 2, 000 feet mean sea level and proceeded ona westerlyheading.The three flight crewmembers and a jumpseat occupant became en-grossed in the malfunction.The National Transportation Safety Board determines that the probable causeof this accident was the failure of the flightcrew to monitor the flight instruments. during the final 4 minutes of flight,and to detect an unexpected descent soonenough to prevent impact with the ground.Preoccupation with a malfunction of . the nose landing gear position’indicating system distracted the crew’s attentionfrom the instruments and allowed the descent to go unnoticed.As a result of the investigation of this accident, the Safety Board has maderecommendations to the Administrator of the Federal Aviation Administration. UNCLASSIFIED Fox-m 1765.2 (11/70) ii ’ Push Forces. 19.Security Classification Classification(of this report)(of this page) 17.Key WordsGo-Around,Initial -4pproach, Malfunction, NoseLanding Gear Position Indicating System, MonitorAircraft Instruments, Unexpected. Descent, Pre-occupation, Altitude Alert, Autoflight System,ing StatementThis document is avail-able to the public throughthe National TechnicalInformation Service, Springfield, Va. 2215 1 -.. l -y .-. . ? I *

3 48; . . EASTERN AIR LINES, INC. N3
48; . . EASTERN AIR LINES, INC. N310EA - ’ FLORIDA 29, 1972 : OF CONTENTS 1. 1 ‘ ry of the Flight...............................1. +,,Injuries ,to PersonsDamage to Aircraft.;. Other Damage....................................Crew Information.................................Aircraft Information.............. Meteorological Information .' ’ to Navigation....1.10 Aerodrome and Ground Facilities 11Flight Recorders.................................. 12Aircraft ‘ Survival Aspects..................... 1. 15’ Tests and Research..............................1. 16 Other Information......................... Analysis and Conclusions......................... Analysis r Probable Cause............................ Appendix A Investigation and Hearing...........Appendix BAirman Information................Appendix C Aircraft Information........... Appendix D Flight Profile.....................Appendix EWreckage Distribution Chart..........Appendix FFlightpath Summary.................Appendix G Mode' A&s es Summary...........Appendix H NTSB Safety RecommendationsA-73-llthru1 I NTSB Safety RecommendationsA-73-39 thru 4343 3 .. .. . . 1 14 . 22 . . I I B _ _. . . . . - _._ __ -... .-. . . . _-- ___-.- . .- - -- -- . - - I- . . I_ . .. _. _. . . . . . . . ‘ . .: ., . I . : File No: I-0016 NATIONAL TRANSPORTATION SAFETY BOARDWashington, D. C. 20591Aircraft Accident ReportAdopted: June 14, 1973EASTERN AI

4 R LINES, INC. N310EA MIAMI, FLORIDA DE
R LINES, INC. N310EA MIAMI, FLORIDA DECEMBER 29, 1972 SY NOPSiS An Eastern Air Lines Lockheed L-1011 crashed at 2342 eastern ; standard time,. December 29,1972, approximateiy 18 miles west- northwest of Miami International Airport, Miami, Florida.The air- .craft was destroyed.There were 163 passengers and a crew of 13aboard the aircraft; 94 passengers and 5 crewmembers received fatal.injuries.All other occupants received injuries- which ranged in severityfrom minor to critical. 1 The flight divertedfrom its approach to Miami International Airportbecause the nose landing gear position indicating system of the aircraftdid not indicate that the nose gear was locked in the ‘down position.Theaircraft climbed to 2, OCO feet mean sea level and foilo\ved a clearance toproceed west from the airport at that altitude.During this time, thecrew attempted to correct the malfunction and to determine whether ornot the nose landing gear was extended.The aircraft crashed into the Everglades shortly after being clearedby Miami Approach Control for a leftturn back to Miami international Surviving passengers and crewmembers stated that the flightwas routine and operated normally befoze impact with the ground. -,. ., The National Trarisportation.Safety Board determines that theprobable cause of this accident ,was the failure’bf the flight crew tomonitor the flight instruments during the final 4 minutes of flight, and.to detect an unexpected descent soon enoughto prevent impact with the ’ Preoccupation with a malfunction of the nose landin

5 g gearposition indicating system distrac
g gearposition indicating system distracted the crew’s attention from theinstruments and allowed the descent to go unnoticed. Y e’,. . e-- . -_- -----. -----. .-- -2 As a result of the investigation of this accident, the Safety Board’has made recommendations to the Administrator of the Federal AviationAdministration. ; :... ’ . . I. INVESTIGATION1. 1 History of the FlightEastern Air Lines, Inc.,Lockheed L- 1011, N31 OEA, operating asFlight 4OJ (EAL 401), was a scheduled passenger flight from the John F.-enne y International Airport (JFK), Jrlmaica, New York, to the MiamiInternational Airport (MIA j, Miami, Florida.On December 29, 1972, the flight departed from JFK at 2120 L/with 143 passengers and 13 crewmembers on board and was cleared t.o MIAin accordance with an instrument flight rules flight plan.The flight was uneventful until the approach to .MIA. The landinggear handle was placed in the“down” position during the preparationfor landing, and green light,which would have‘ indicated to. the flight- crew that the nose landing gear was fully extended and locked, failed toilluminate.The captain recycled the landing gear, but the green lightstill failed to illuminate. / EAL 401 called the lMIA tower and stated, “Ah, towcrfs; this is Eastern,ah, four zero one,it looks like we’re gonna have tocirclewe don’t have a light on our nose gear yet. ” 2334:14, the tower advised, “Eastern four oh one heavy, roger, pull up,climb straig’nt ahead to tw

6 o thousand, go back to approach con-trol
o thousand, go back to approach con-trol, one twenty eight six. ” 2334:21, ;he flight acknowledged, “Okay, going up.to twothousand,one twenty eight six. ” At 2335:09, EAL 401 contacted MIA approach control and reported,“All right, ah,approach control,Eastern four zero one, we’re rightover the airport here and climbing to two thousand feet, in fact, we’just reached two thousand feet and we’ve got to get a green light on ournose gear. Ii At 2335:20, approach control acknowledged the flight’s transmissionand instructed EAL 401 to maintain 2, 000 feet mean sea level and turnto a heading of 360 magnetic..-The ne heading was acknowledged byEAL 401 at 2335:28. All times herein are eastern standard, based on the 24-hour clock. . “ 2336:04, the captain instructed the first officer, who was flying 9 the aircraft, to engage the autopilot. The first officer acknowledgedthe instruction. -, . . At 2336:27, MIA approach control requested, “Eastern four oh one,turn left heading three zero zero.”EAL 401 acknowledged the requestand complied. -L; The first officer successfully removed the nose gear light lens - assembly, but it jammed when he attempted to replace it. . At 2337:08, the captain instructed the v to enter theforward electronics bay,below the fli ht deck, to check visually the 2& alignment of the nose gear indices. - At 2337:24, a downward vertical acceleration transient of 0. 04 gcaused the aircraft to descend 100 feet; the loss in. altitude was arrestedby a pitch

7 up input.At 2337:48, approach control
up input.At 2337:48, approach control requested the flight to turn left to aheading of 270° magnetic.EAL 401 acknowledged the request and turnedto the new heading.. Meanwhile, the flightcrew conti.nued their attempts to free the nose 1 ‘ ear position light lens from its retainer, without success. .At 2338:34, 3 the captain again directed the second officer to descend into the forward . electronics bay and check the alignment of the nose gear indices.” ’ * At 2338:46, EAL 401 called MIA approach control and said, “Easternfour oh one’11 go ih, out west just a little further if we can here and, ah,see if we can get this light to come on here. ” MIA approach controlgranted the request.From 2338:56 until 2341:05, the captain and the first officer dis-.cussed the faulty nose gear position light lens assembly and how itmight have been reinserted incorrectly. y----- 2340:38, a half-second C-chord, which indicated a deviation of f 250 feet from the selected.altitude, sounded in the cockpit. P- crew-member commented on the C-chord. --. ----. __.________- -- hJ%pitch change to correct for the 10~s of altitude was recordedt,.- . :: ~e~~~---m-m~~.- Pro er nose.gear extension is *indicated by the .physical a!igntnent oftwo rods on the landing gear linkage.With the nose wheelwell lightilluminated, these rods may be viewed by me of an optical sightwhich is located in the forward electronics bay, just forward of thenose w - 5 - Shortly after 2341,the second officer raised

8 his head into thecockpit and stated,

his head into thecockpit and stated, “I can’t see it,its pitch dark and I throw thelittle light, I get, ah, nothing. ” The flightcrew and an Eastern Air Lines maintenance specialistwho was occupying the forward observer seat then discussed the oper-ation of the nose wheelwell light. After*ward, the specialist went intothe electronics bay to assist the second officer.At 2341:40, MIA approach control asked, “Eastern, ah, four ohone how are things comin’ along out there? ” This query was made a few seconds after the MIA controller notedan altitude reading of 900 feet in the EAL 401 alphanumeric data block -on his radar display.The controller testified that he contacted EAL401 because the flight was nearing the airspace boundary within hisjurisdiction.He further stated that he had no doubt at that momentfabout the safety of the aircraft. M.omentary deviations inaltitude in- : formationon the radar display,he said, are not uncommon; and morethan one. scan on the display would be required to verify a deviation : requiring controller action. .: At 2341:44, EAL.401 replied to the controller’s query with, “Okay, we’d like to turn’ around and come, come back in, Ii and at 2341:47, approach control granted the request with; “Eastern four oh one turnleft heading one eight zero. ” EAL 401 acknowledged and started theturn. : the first officer said,“We did something to the altitude. ” The captain’s reply was, “What? ” At 2342:07, the first officer as

9 ked, “We at two thousand, \I &#
ked, “We at two thousand, \I ” and the captain immediately exclaimed, “Hey, what’s happening h here? ” �- . SC. At 2342:10, the first of six radio altimeter warning “beep” soundsbegan; they ceased immediately before the sound of the initial groundimpact. At 2342:12, while the aircraft was in a left bank of 28 it crashed. * into the Everglades at a point-.lg. 7.statute miles west-northwest ofMIA (latitude 25O52 N., lobgitude 8 W.). The aircraft wasdestroyed by the impact. , . . Local weather at the time of the accidentswas clear, with un- -y restricted visibility.The accident occurred in darkness, and therewas no Moon. ,_. .: .._ _ __ _._ _. ..__ ._-e-----e -6Two ground witnesses had observed the aircraft shortly beforeimpact to be at an altitude that appeared low.1.Injuries to PersonsInjuriesNonfatal 2% l 0 . ..__ two nonrevenue passengers,one occupying an observer seatin the cockpit and the other seated in the,first-class section of the cabin.The accident survivors sustained various injuries; the most preva-lent were fractures of the ribs, spine, pelvis, and lower extremities.Fourteen persons had various degrees of burns;Seventeen personsreceived only minor injuries and did not require hospitalization:Post-mortem examination of the captain revealed a tumor whichemanated from the right side of.-the tentorium in the cranial cavity. The tumor displaced and thinned the adjacent right occipital lobe of thebrain.The lesser portion of this meningioma extended

10 downwa into. - . ._ superior-porti
downwa into. - . ._ superior-portion of the rightcerebella hemisphere.The tumor’ -. measured 4. 3 centimeters laterally, 5. 7 centimeters vertically, and4. 01.centimeters in an anterior-posterior direction. 1 Damage to AircraftThe aircraft was destroyed.Other DamageNone. One nonrevenue passenger and one other passenger succumbed to . their injuries more 7. days subsequent to the accident.14 CFK430, section 430. 2, riquires these deaths be classified herein . “nonfatal. ” , . 1. 5 Crew Information __ __ -. ._ ~. - L .- . . . _ ,,-, - _, __i : . .- . . I-. .. . . . . The captain, the first officer,and the second officer were certifi-cated to serve as crewmembers for this flight.(See Appendix B for , information. ). .. _ *. ‘ I . ’ An Eastern -4ir Lines L-101 1 maintenance specialist, one of thetwo nonrevenue passengers,occupied the forward observer seat duringthe flight from JFK. 1: 1; 6. Aircraft Information- Y . .. . - - i ‘ . \ .._ -.-. . Lockheed L- 1011,’ N31 PEA,: was opkrate.d. by _. _~ . ..s ._ Air Lines; Ino. ‘ The ai;cra~ and .ma-intained in accordance‘ with Fe Aviation- Adrriinistration (FAA) .I .. : . . . , . -- (See Appendix C for detailed . . . . ,. - . -_ )- ~ ;. ;. : 2 .: _:: 1. 7 Metebrblogical Informgtion ‘ ” ,-- T . , _ , ( ,: I, . . .._ :. . . ‘ _.. - . -.A-The-official surface weather observations’&-: M

11 IA]:Eiefore .and after . . 1 : --
IA]:Eiefore .and after . . 1 : -- : ‘ . ; , -. :- j time of ‘the accident ‘were, in part,. as follots: ‘ ._ 1 _ : ... �‘ :i ‘ _.,. :y __ i. “...-,-.-. : ‘ . ; .- .:( - 2, 500 feet scatteted;l.Gisibilitly 0 miles,. .l.. temperature 72 F.; dew point 59O F. , -&ind..O8po at _. W. __ : 7 knots,‘. altimeter setting 30. 2 inches. *.. - . , ‘ . . .__ . --2350 - 500 feet scattered, visibility 10 mile‘ 72O F., ooint 59O F ‘ wind 080° at . 8 knots, altimeter setting 30. 19 inch:;. 1.8 Aids to Navigation _ - flight path of the aircraft being monitored by MIA approachcontrol.. aide. 2 by the Automated Radar Terminal Service (ARTS-III) _ ‘ ..1 -. - _ _ . :. . :y i : _ ARTS-III is a ‘system which automatically procksses the transponder . . : -- . . . ., . . ‘ beac:on. from ali a specific- ___.:.: . . . . rangk of ‘ app;oich.-c:bntrol:r-~~~r ,q.U c,.om$ut.kd data -. __ i 7.; I . . 1:. -- :.- are ‘ on- a d .blO-ck next t,oleach aircraft’s updated . :;;.:::7.- ;- the air. traffic cd~t;oller]ls.i~d.r :djsp ;;The information -. provided to the controller iS groundspeed in . kfibts, &$;. &&-fh~ ‘ &$&;&t bein-&t]ja;ked has a . . __...,.. . . . . ._._ .:. . _ -_ ‘ _ -. M0DE.C capability; pressure-altitude in 100-f& increments. . -. -81. 9 C

12 ommunicationsNo difficulties with commun
ommunicationsNo difficulties with communications between the flight and the airtraffic control facilities were reported.1. 10 Aerodrome and Ground Facilities -. Not involved.1. 11 Flight RecordersN31 OEA was equipped with a Lockheed Aircraft Service Co. ,Model. 209, expandable digital flight data recorder system (DFDR),serial No. 105.This is a new type of recorder which has the capabilityto record numerous performance parameters on l/4-inch magnetictape.Recorded data are retrieved and printed out. In this case, 62parameters were printed out. This large number of performanceparameters provided the investigators a comprehensive and detailedhistory of flight.In addition to the normal description of the airspeed,altitude, heading,and vertical a.cceleration of the aircraft, availabiiity of additional data relating to engine thrust, control surface position,roll angle, pitch attitude, angle of attack, etc., provided the basis fora comprehensive aerodynamic ‘evaluation and the basis for the analysisof theautopilot and autothrottle systems.The aircraft was also equipped with a Fairchild Ivbdel A- 100Cockpit Voice Recorder (CVR), serial NO. 3125. The CVR tape wasrecovered intact,and a transcription was made of the voices andsounds commending at the time of the crew’s initial call to the MIATower. (See Appendix for details. ) 1.12 Aircraft Wreckage The terrain in the impact area was flat marshland, covered withsoft ‘mud under 6 to 12 inches of water.The elevation at the accidentsite was approximately 8 feet above sea level.The lef

13 t outer wing structure impacted the grou
t outer wing structure impacted the ground first; the No. 1 and then the left main landing gear, followed immediately. Theaircraft disintegrated,scattering yreckage over an area approximately1,600 feet long and 300 feet-wide.No complete circumferential c ros s - section remained of the passenger compartment of the fuselage, whichwas broken into four main sections and numerous small pieces.Theentire left wing and left stabilizer were demolished. No evidence of in- - flight structural failure,fire, or explosion was found.. . . .- The nature of the breakup precluded determination, by physicalmeansof the integrity of the primary flight control system beforeimpact.The primary flight control positions were recorded, however,by the Dl?.DR. These data show that the control columns were in anaircraft noseup position when the crash occurred.The DFDR recorddepicted the spoiler positions as retracted; the three intact spoilers onthe remains of the right wing were found, by inspection, to be retracted.The wing flap lever in the cockpit was set at 18O flap extension, and theextension of the inboard jackscrew on the inboard section of the rightwing flap corresponded with that setting.The leading edge slat sectionson the intact portion of the right wing were found fully extended.Thewing flap and leading edge slat positions agreed with the DFDR record.The landing gear lever was in the geardown position . The rightmain landing ‘which remained in place, was down and locked.The left main landing gear and the nose landing gear, along with portionsof their

14 attach structure,were separated from th
attach structure,were separated from the airplane and were ens ive ly damaged.The nose eear down-and-locked visual indicitfor and the nose wheelwell servic..e.light.~assemb.Ly~~ere~~othinplace and operative.---The nose gear warning light lens assembly was jammedin a position that was 90° clockwise to and protruding a quarter of aninch from its normal position.Both bulbs in the ILnifWprprntit. Except for the altitude portion of the first officer’s Air Data Computer (ADc), both ADC and the Pitot static instruments operated.satisfactorily during functional testing.The first officer’s ADC sus-tained impact damage,and the altitude sensing portion of the unit couldnot be tested.The captain’s ADC altitude, true airspeed, and calibratedairspeed validity flags were monitored by the DFDR. NO failures wereThe captain’s and first officer’s altimeters both indicated approxi-mately 75 feet below sea level.The readings on the captain’s airspeedand vertical speed indicators were 198 knots and 3, 010 feet per minutedown.The readings on the first officer’s airspeed and vertical speedindicators were 197 knots and 2,950 feet per minute down.The captain’radio altimeter was set for a decision height of 30 feet, whereas the firstofficers radio altimeter was set for 5i feet.The radio altimeter auraltone,which sounds during descent at 50 feet above the selected decisionheight,was recorded on the CVR seconds before impact.Functional tests of the captain’s and first officer’s attitude directorindicators

15 revealed that both units were capable of
revealed that both units were capable of satisfactory operation. - 10 - The two autopilot-engage switches and the two flight directorsystem select switches were found in the “off” position.An altitudeof 2, 000 feet was found selected in the altitude select window.Thheading select window shovied a. 180 heading selection. The verticalspeed window showed a descent of 2,500 feet per minute.Preimpact malfunction was not evident in the examination of theaircraft hydraulic and electrical systems.Until the aircraft crashed,the DFDR recorded proper operation by the various controls and instru-ments which used hydraulic and electrical power.The No. 1 engine separated from its attach structure and cameto rest near its point of’initial impact.The No. 2 engine remained inplace, and was relatively undama.ged. The No. 3 engine separatedfrom its attach structure and came to rest near the remains of the rightwing.All engines showed evidence of leading edge damage to the fanblades, breakage of the low-pressure (LP) fan blades, or blade bendingin a direction opposite to the engine rotation.All of the LP fan discswere intact and secured; operational distress was not evident.Theengine pressure ratio (EPR) values of each engine were recorded by the The record showed that the EPR values of the N. 1, 2, ‘ and 3 engine were 1. 083, 1. 073, and 1. 066, respectively,. at the time - of ground impact. ., 1. 13 Fire _. \ There was no evidence of in-flight fire or explosion. After impact,a flash fire developed from sprayed fuel.Some of the burning

16 fuelpenetrated the cabin area,causing 14
fuelpenetrated the cabin area,causing 14 passengers to suffer various degreesof burns on exposed body surfaces.1. 14 Survival Aspects hr The search for the aircraft and the initial rescue efforts tiere coordinated by the United States Coast Guard, which was notified ofthe accident by Miami tower controllers. Helicopters were airbornealmost immediately from the Coast Guard station at Opa Locka, Florida.The crash site was !ocatcd about 15 to 20 minutes later. Despite the -.total darkness and the swampy condition of the site, as well as therelative remoteness of one group of survivors from another,rescueefforts were started immediately and were completed approximately4 hours later,Sixty-eight survivors were airlifted to local hospitals. . . 11 - , Most of the survivors were located in the vicinity of the cockp.it area, the midcabin service area, the overwing area, and the empennagesection; these sections were located at the far end of the wreckzge path.In contrast, most fatalities were found in the center of the crash path.Crushing injuries to the chest were the predominant causes of death.1. 15 Tests and Research i Performance tests were conducted at Miami on January 7, 1973,using the Eastern Air Lines L-l 011 simulator, and on January 9, 1973,using an L- 1011 test aircraft.Before the flight tests, the computers(except the roll computers) from the accident aircraft’s Avionic FlightControl System (AFCS), and a new flight data recorder were installedin the test aircraft.In addition to the tests in Miami,the Safety Board organized anAi

17 rcraft Performance Group at the Lockheed
rcraft Performance Group at the Lockheed-California Company,Palmdale, California,to analyze the aerodynamic characteristics ofthe Lockheed L-1011 in relation to the flight performance characteristicsof the accident aircraft.The DFDR and the CVR readouts from theMiami test aircraft were used by the group in the comparative analysis.,This group also conducted a collateral study of the aircraft’s autopilotand autothrottle systems,based on normal operation, to determine ifthey were operational during the final moments of Flight 401.This . . The accident flightpath was consistent with theestablished aerodynamic characteristics of the L-1011. ..- ^ .-_.____.____________ _--A--, The autopilot was engaged at various times during theflight, and was in the control wheel steering (CWS) pitchmode during the last 288 seconds of the flight.3.The autothrottle system was not in use during the finaldescent.The AFCS computers were checked for operation. The computersfor pitch control and autothrottle were found operative. Subsequent flighttests of the computers in th.e test aircraft simulating the flightpath ofFlight 401 were satisfactory. . Autoflight engage switches, altitude select controls, and speedcontrol system selectors in the AFCS also checked satisfactory.Theautopilot pitch control servo that interfaces the autopilot with the pri- mary flight controls likewise was bench tested with satisfactory results. , 12 - b :. The throttle control servo in thethrottle clutch system were tested,speed control system and the -_ and no discrepancies we

18 re uncovered. \ The air data computers a
re uncovered. \ The air data computers and the associated indicators were foundto function satisfactorily.The CVR showed that the radio altimeters were operating at thetime the aircraft impacted the ground. ’ 16 Other InformationThe Lockheed L-1011 Avionic Flight Control System is composedof four major subsystems:the autopilot flight director system, the yawstability augmentation system, the speed control syst.em, and the flightcontrol electronics system. ’ The autopilot flight director system (APFDS), which providesautopilot and flight-director pitch and steering commands, has tworoll and two pitch computers.One set is designated the “A” system -iz . . \I? . . .and the other. the “B” system. : - . $4 - . system relates to autopilot on.the captain’s side; the ” “A” and to the flight director. . T system relates to autopilot “B” and tothe flight director on the first officer’s side.Each pitch and roll corn-‘puter has- a dual channel with a self-monitoring capability. .Both autoiz - pilots cannot be operated simultaneously,except in the autoland mode. Ihe function and operation of the autopilot are displayed on the captain’and the first officer’s panels through AFCS warning and AFCS mode annunicators. The APFDS engage panel, the Nos. 1 and 2 VHF navi- gat ion panels,the autothrottle system panel, the heading and pitchmode panel,a navigation mode panel,and the altitude select panelare all located on the glare shield; they are the means by which

19 thevarious functions of the AFCS are sel
thevarious functions of the AFCS are selected. 9 The basic mode of autopilot system operation is control wheelsteering,In this mode of operation,the autopilot provides attitude 1. ‘ stabilization with attitude changes effected by the application of light. . forces to the control wheel by the crew. . . . The autopilot,when eng’aged in‘a command mode of operation,will provide total control of the aircraft in accordance .with selected ! - heading,. pitch,or navigational system inputs.In this mode of oper- the autopilot signals are derived from various computers and. .sensors in the integrated avionics flight control system. . I . - 13 - When operating in any mode,the selected heading or pitchcommand function may be disengaged by an overriding 15-pound force i applied to the respective, i. e. , lateral or pitch, control system through \ the control wheel.If the force is applied to the pitch control system, i only pitch axis control will be effected,reverting to the basic attitude -. stabilization mode of operation.If the force is applied to the roll control . system, the autopilot engage lever will revert to the CWS position.The autopilot may be completely disengaged by moving the engagelever to “OFF” or by operating a button switch on either control wheel.An additional safety featu.re is incorporated into the autopilot design bylimiting the control wheel induced force such that a pilot may at anytime manually override autopilot signals.The altitude hold mode of operation is unique in that, although itis a c

20 ommand function,it may be engaged when t
ommand function,it may be engaged when the autopilot is selectedto provide either basic CWS or Command operation.When altitude holdis selected, the autopilot provides pitch signals to maintain the altitudeexisting at the time of engagement.As described, pilot-applied pitch ! forces on the control wheel will cause disengagement of the altitudehold function,reverting the autopilot pitch channel to attitude stabili-zation sensitive to control wheel inputs.The autopilot engagement leverwill, how ever,remain in the previously selected position, i. e., either :CWS or sommand. It is possible, therefore, to disengage altitude holdwithout an accompanying “CMD DISC”warning appearing on the captainor first officer annunciator panels.The normal indications of such an ., occurrence would be only the extinguishing of the altitude mode selectlight on the glage shield and the disappearance of the “ALT” annunci- ’ ation on both annunciator panels.The two pitch computers in N310EA were not matched.The pitchoverride force required to disengage the altitude hold function in com-puter “A” was 15 pounds, whereas in computer “B” it was 20 pounds.As a result of the mismatch, it would be possible, with the “A” auto-pilot system engaged,to disengage the “A” XFCS computer, but not the “B” AFCS computer.In this situation, the altitude mode select lightwould remain on, the “ALT” indication on the captain’s annunciatorpanel would go out,and the same indication on the first

21 officer’annunciator panel would re
officer’annunciator panel would remain on,which would give the first officer the erroneous indication tnat the autopilot was engaged’in the altitudehold mode. - 14 - . ANALYSIS AND CONCLUSIONS.It was concluded from the investigation and the data obtainedfrom tests,that the aircraft powerplants, airframe, electrical and s static instruments, flight controls,and hydraulic and electricalsystems were not factors contributing to this accident. ‘ . Investigation of the Air Traffic Control responsibilities in thisaccident revealed another instance where the ARTS III system con-ceivably could have aided the approach controller in his ability to detectan altitude deviation of a transponder-equipped aircraft, analyze thesituation,and take timely action in an effort to assist the flightcrew.In this instance, the controller, after noticing on’his radar that thealphanumeric block representing Flight 401 indicated an altitude of 900 feet, immediately queried the flightsas to its progress. An immediate i positive response from the flightcrew, and the knowledge that the i ARTS III equipment, at times,indicates incorrect information for up f to three scans,led the controller to believe that Flight 401 was in no ; immediate danger.The controller continued with his responsibilities ’ to the five other flights within his jurisdiction. 2 The Board recognizes that the ARTS III system was not ‘to provide terrain clearance information and that the FAA has no proce dures which require the controller to provide such a servi

22 ce. However, . it would appear that ever
ce. However, . it would appear that everyone in the overall aircraft control system hasan inherent responpibility to alert others to apparent hazardous situations,even though it is not his primary duty to effect the corrective action.The destruction of the fuselage,with the possible exception of thecockpit area,was to such an extent that the generally accepted factorswhich affect occupant survivability could not be applied.Survivabilityin accidents generally is determined by these factors: a relatively intactenvironment for the occupants,crash forces which do not exceed thelimits of human tolerance,adequate occupant restraints, and sufficientescape provisions.A useful distinction may, therefore, be madebetween impact survival and postcrash survival. Impact survival impliesthat the crash forces generated by the impact were of a nature which didnot exceed the limits of the occupant’s structural environment nor theoccupants physiological limits.Postcrash survival is determined bythe occupant’s successful escape from his environment before conditionsbecome intolerable as a result of fire, water immersion, or other - 15 - . - postcrash conditions.This requires nonincapacitation and adequateexit provisions.From the above,it is evident that two important factors affectingimpact survival were exceeded in this accident: loss of environmentalprotection and loss of restraint.The injuries of most of the fatalitiescan be attributed directly to these factors.Therefore,spite the factthat 77 occupants survived,the Board cannot place this accident in

23 thesurvivable category.The high surviva
thesurvivable category.The high survival rate is difficult to explain.The location ofthe majority of survivors near the ‘larger fuselage sections would in-dicate that they remained with these sections until the velocity wasconsiderably reduced or until thes-e sections came to a stop.Althoughthe fuselage shell was torn away,thereby exposing the occupants toexternal hazards,the fuselage structure apparently did not impingeon these survivors.The Board believes, therefore, that the 76 cabinoccupants survived because either their seats remained attached tolarge floor sectionsor the occupants were thrown ciear of the wreckageat considerably reduced velocities.A final survival factor which deserves attention is the design ofthe passenger seats in this aircraft.These seats incorporated emnergy absorbers in the support structure.Additionally,in contrast with theconventional floor tiedown arrangement of aircraft seats, each of theseat units in this aircraft was bolted to a platform, which in turn wasfitted to tracks attached to basic aircraft structure.It was noted thatmany of the seat units remained attached to these platforms and thatfailures occurred because the basic aircraft structure was compromised,rather than the platform attachments.Although many seat leg failuresalso were noted, these failures occurred because forces were applied inan aft direction; the seats are stressed to withstand much lower loadsin the aft direction than in a forward direction.In fact, the FederalAviation Regulations do not have a stressrequirement in the aft direct

24 ionfor aircraft seats.The Board is of th
ionfor aircraft seats.The Board is of the opinion that the design of thepassenger seats in this aircraft materially contributed to the survivalof many occupants.The thrust of the investigation was focused on ascertaining thereasons for the unexpected descerit.The areas considered were: I - - 16 - Subtle incapacitation of the pilot. . The autoflight system operation.3Flightcrew training.4Flightcrew distractions.Subtle incapacitation ha to be considered in view of the finding ofa tumor in the cranial cavity of the captain.The medical examiner sug-gested that the space-occupying lesion could have affected the captain’vision particularly where peripheral vision was concerned.Additionally,in the public hearing held in connection with this accident, expert testi-mony revealed that the onset of this type of tumor is slow enough to . individual to adapt, by compensation, to the lack of peripheralvision so that neither he nor other close associates &ould.be aware ofany changed behavior.It was also noted that the extent of peripheralvision loss, .in this case,could not be predicated with any degree ofaccuracy on iti size and location in the cranial cavity. ,, It was hypothesized that if the captain’s peripheral vision was *. severely impaired,he might.:not have detected movements in the “ .and vertical speed indicators- while he watched the first -: and replace the npse gear light lens.However, the 1: s family,. close friends,and fellow pilots advised that he showedno signs of visual‘difficulties in the performance of his d

25 uties and in q other activities requiri
uties and in q other activities requiring peripheral vision.In the absence of anyindications to thercontrary, the Board believes that the presence ofthis tumor in the captain was not a causal factor in this accident. . In considering the use of the autoflight system, it was noted thatthe go-around was flown manually by the first officer until 2336:04 when the captain ordered engagement of the autopilot.The affirmativereply by the first officer implies that the autopilot was engaged at thistimeVerification of such action‘was provided by the aircraft per-formance group analysis of the DFDR readout which showed pitch control .: .,, : - 17 - -..-- - ___.. - .____ surface motions indicative of autopilot control in either altitude holdor pitch CWS. _ Which of the autopilots was engaged, i. e. ,syste“A” or system “B, could not be determined.Testimony by pilots atthe public hearing indicated that the first officer would have probablyengaged system “B” to the command position with the altitude hold and-- heading select functions selected,in accordance with general practices.At the same time,the first officer probably selected 2, 000 feet intothe altitude select/alert panel. . . At approximately 2337,some 288 seconds prior to impact, theDFDR readout indicates a vertical acceleration transient of 0. 04 gcausing a 200-f. p. m. rate of descent.For a pilot to induce such atransient, he would have to intentionally or inadvertently disengagethe altitude hold function.It is conceivable that such a transientcou

26 ld have been produced by an inadvertent
ld have been produced by an inadvertent action on the part of thepilot which caused a force to be applied to the control column.Sucha force would have been sufficient to disengage the altitude hold mode.It was noted that the pitch transient occurred at the same time thecaptain commented to the second officer to “Get down there and see ifthe . . .nose wheel’s down. ” If the captain had applied a force to thecontrol wheel while turning to talk to the second officer, the altitudehold function might have been accidentally disengaged! Such anoccurrence could have been evident to both the captain and first officerby the change on the annunciator panel and the extinguishing of the ,altitude mode select light. ._- If-autopilot system “A” were engaged,howeverthe discrepancy in the disengage force comparators, i. e., It was concluded that the autopilot was engaged at various times - throughout the flight from JFK.A complete mode assessmentsummary for the pertinent portions of the 27-minute period precedingimpact is contained in Appendix G.In attempts to distinguish betweenautopilot “ON” and “OFF, ” considerable reliance was placed on DFDRdata which showed the ratio between pilot and copilot control cable systeminput motion in the roll axis,since the ratio varies between manualand autopilot operation.This characteristic of the L- 1011 lateralcontrol system,verified by ground and flight tests, was used to dis-tinguish between autopilot“ON” and “OFF” whenever there wasappreciable roll activ

27 ity., During lateral maneuvering with CW
ity., During lateral maneuvering with CWS,this ratio becomes less dkfinitive, and, although autopilot “OX”” and“OFF” status can be determined, positive identification of the selectedmode becomes more difficult- - 18 - the mismatch between computers “A” and “B” would become asignificant factor in this analysis. Because of this mismatch andthe system design,a force eserted on the captain’s control wheelin excess of 15 pounds, but less than 20 pounds, could result in dis-engagement of the altitude hold function wit’hout the occurrence of acorresponding indicption of the first officer’s annunciator panel.This would lead to a situation in which the first officer, unawarethat altitude hold had been disengaged, would not be alerted to theaircraft altitude deviation.If the autopilot system “B” was engaged,as is believed to have happened,such a situation could not haveoccurred since a force in excess of 20 pounds would have been requirecl to disengage the altitude hold function and both annunciator panelswould have indicated correctly.Therefore, the Board concludes thatthe mismatched pitch computers in the autoflight system were not acritical factor in this accident.However, it is significant that recognition of the aforementioned lOO-foot loss took 30 seconds after the 0. 04 g pitch transient occurred,and after a heading change was requested by approach control.TheDFDR readout indicates a 0. 9 pitchup maneuver coincident with achange of heading.It was concluded from the DFDR

28 analysis of lateralcontrol system motio
analysis of lateralcontrol system motions that the heading select mode was used for thelast 255 seconds of flight to control the aircraft to a heading of 270 Since selection of the new heading would have required action by thefirst officer,which included attention to the autopilot control panel,it is reasonable to assume that he’ should have been aware of theselected heading select functions at this time.It is also reasonableto assume that the autopilot was set up to provide pitch attitude stabili-zation sensitive to control wheel inputs and heading select, whereinlateral guidance signals were provided to achieve and maintain the 270 heading.In the pitch attitude stabilization mode, the aircraft will respondto intentional or unintentional movements of the control wheel. Furtbcr- while the aircraft is operating in this mode, the effect of aircraftthrust changes,without compensating pitch attitude control inputs, willbe directly related to changes in vertjc sp’A series of reductions in power began 1.6.O seconds before impact.The power reductions and slight nosedown p:ifc.h.control movements to-gether were responsible for the unrecognized .de,g which followed. . . . Extensive f!ight testing and simulation studies.of N310EA entireSpeed Control System (SCS) (autothrottle) were conducted to identify the - 19 - reason for the series of reductions in thrust during the last fewminutes of the flight.Thrust reductions generated by the N310EA autothrottle components installed in the test aircraft were dissimilarto those reduc

29 tions recorded on the DFDR from the acci
tions recorded on the DFDR from the accident aircraft.In one series of flight tests, the autothrottle speed reference wasset to 175 knots indicated airspeed (IAS);and a descent rate of 200feet per minute was established. Theairspeed was maintained towithin f 3 knots of the reference speed by the SCS, until the auta- limits were reached (flight idle thrust}. Suchcontrol during the flioht of N301EA was not evident; a 15-knot increase .F! in airspeed did occur,‘with throttle authority still available.Comparison of the autothrottle system simulation data with Flight 401’airspeed and acceleration data confirmed that the throttles wouldhave been retarded to the flight idle position relatively quickly.Reference to the DFDR shows that power on the No. 3 enginewas inc reas ed slightly,1 minute before reduction of power on theNos. 2and 3 engines (the initiation of the descent profile). This isa normal manual adjustment typically made by a pilot, and cannotbe accomplished by the autothrottle system. Additionally, the speedfound set on the autothrottle selector dial was 160 knots, a speedwell below that attained or maintained during the last 4 minutes offlight.An indication that the throttles were not retarded by a properlyoperating autothrottle system is the sequence in which the power wasreduced.The first power reduction occurred on the N. 2 and 3engines 160 seconds before impact.In the second reduction, thepower on the No.1 engine was matched with the power on the N. 2and 3 engines.Finally, the power onthe No. 1 engine was retardedf

30 or more than 10 seconds before reduction
or more than 10 seconds before reduction of power in the two otherengines.The throttles were clutched together and driven simultaneouslyby one servo.If the autothrottle system was “on, ” only intermittentand random failures in the clutch system would have producedasymmetrical reduction of power similar to that typical of manualthrottle movement.Since the autothrottle system of N310E-4 wasfound to have been functional, the Board does not believe that thissystem was involved in the reduction of thrust.Another explanation of the thrust reductions would seem to beone of two alternatives --either an inadvertent or an intentional actionby one or both of the pilots.The captain might have inadvertently - 20 - bumped the throttles with his right arm when he leaned over thecontrol pedestal to assist the first officer.Similarly, the firstofficers left arm might have accidentally bumped the throttleswhile he was occupied with the nose gear indicating system.Because the EPR reductions reflected by the DFDR do even out,at times,one of the pilots might have noted an uneven EPR display(which usually accompanies movement of a throttle), and his re- ’ action might have been to reposition the throttle without referenceto the flight instruments.The other alternative is that one of the pilots intentionally ! reduced thrust power when he noted that the speed of the aircraftwas exceeding the desired speed (160- 170 knots) for the flight i regime involved.The intentional adjustment, similarly, most prob- ably was made with reference to the airspee

31 d indicators only. Lf the crew relied o
d indicators only. Lf the crew relied on the autoflight system to maintain the aircraft’ altitude, it is conceivable that a correction in airspeed might have I been made without reference to other instruments. Of the two i possibilities,the Board believes that the throttles were intentiona!ly retarded by one or both of the pilots.Regardless of the way in which the status of the autoflightsystem was indicated to the flightcrew,or the manner in which thethrust reduction occurred, the flight instruments (altimeters, ’ vertical speed indicators, airspeed indicators, pitch attitude indi- and the autopilot vertical speed selector) would have indi-cated abnormally for a level-flight condition.Together with thealtitude-alerting, l/2-second, C-chord signal, the flight instrumentindications should have alerted the crew to the undesired descent.The throttle reductions and control column force inputs which were made by the crew,and which caused the aircraft to descend, 1 suggest that crewmembers were not aware of the low force gradient ,I input required to effect a change in aircraft attitude while in CWS. \ The Board learned that this lack of knowledge about the capabilitiesof the new autopilot was not limited to the flightcrew of Flight 401.Pilot training and autopilot operational policies were studied exten-sively during the field phase of the investigation, and were discussed,at great length,in the public hearing connected with this accident.Although formal training pro\*ided adequate opportunity to becomefamiliar with this new concept of

32 aircraft control, operationalexperience
aircraft control, operationalexperience with the autopilot was limited by company policy.Company operational procedures.did not permit operation of the aircraftin CWS; they required all operations to be conducted in the commandmodesThis restriction might have compromised the ability of ‘ ed, T-L- pilots to use and understand the uniquautopilot .e CWS feature of the newHowever,the Board believes that the present Eastern AirLines training program is adequate but is in need of more frequentquality control progress checks of the student during the groundschool phase of the training and an early operational proficiency followup check in the flight simulator after the pilot has flown theL-1011 in scheduled passenger service.Another problem concerns the new automatic systems whichare coming into service with newer aircraft and being added toolder aircraft.Flightcrews become more reliant upon the function-ing of sophisticated avionics systems,and their associatedto fly the airplane.This is increasingly so as the reliability of suchequipment improves.Basic control of the aircraft and supervisionof the flight’s progress by instrument indications diminish as othermore pressing tasks in the cockpit attract attention because of theoverreliance on such automatic equipment.Pilots’ testimm bdic&.eri that dependence on the reliability ’ and capability of the autopilot is actually greater than anticipated in3 its early design and its certification.This is particularly true inthe cruise phase of flight. However, in this phase of flight

33 , theautopilot is not designed to remain
, theautopilot is not designed to remain correctly and safely operational,without performance degradation,after a significant failureoccurs. any event, good pilot practices and company training dictate - that one pilot will monitor the progress of the aircraft at all timesand under all circumstances.The Board is aware of the distractions that can interrupt the ’ routine of flight.Such distractions usually do not affect other flightrequirements because of their short duration or their routineintegration into the flying task,However,the following took placein this accident:1.The approach and landing routine was interrupted by anabnormal gear indication. -1 2.The aircraft was flown to a safe altitude, and the autopilotwas engaged to reduce workload, hut positive delegation ofaircraft control was not accomplished. I ..- -_-_.. .------ .._ 22 - The nose gear position light lens assembly was removedand incorrectly reinstalled. \ The first officer became preoccupied with his attemptsto remove the jammed light assembly.The captain divided his attention between attempts to helpthe first officer and orders to other crewmembers to tryother approaches to the problem.The flightcrew devoted approximately 4 minutes to thedistraction,with minimal regard for other flightrequirements.It is obvious that this accident, as well as others, was not thefinal consequence of a single error,but was the cumulative result of , several minor deviations from normal operating procedures which ‘ triggered a sequence of events with disastrous results. 2.2 (a) F

34 indings 1. The crew was trained, qualifi
indings 1. The crew was trained, qualified, and certificated forthe operation.2.The aircraft was certificated, equipped, and maintainedin accordance with applicable regulations. 8, There was no failure or malfunction of the structure,powerplants, systems,or components of the aircraftbefore impact,except that both bulbs in the nose landinggear position indicating system were burned out.4.The aircraft struck the ground in a 2S left bank witha high rate of sink.5.There was no fire until the integrity of the left wingfuel tanks was destroyed after the impact. 6. The tumor in the cranial cavity of the captain did notcontribute to the accident. 7.The autopilot was utilized in basic CWS.8.The flightcrew was unaware of the low force gradientinput required to effect a change in aircraft attitudewhile in C WS . 9. The company training program met the requirementsof the Federal Aviation Administration. \i The three flight crewmembers were preoccupied in anattempt to ascertain the position of the nose landinggearThe second officer, followed later by the jump seatoccupant, went into the forward electronics bay tocheck the nose gear down position indices. ‘ The second officer was unable visually to determinethe position of the nose gear. -zz J&e The flightcrew did not hear the aura! altitude alertwhich sounded as the aircraft descended through1, 750 feet m. s. 1.14.There were,,several manual thrust reductions duringthe final descent. 1 The speed control system did not affect the reductionin thrust.16.17.The flightcrew did not monitor the flight inst

35 ruments , during the final descent until
ruments , during the final descent until seconds before impact. 1 The captain failed to assure that a pilot was monitoringthe progress of the aircraft at all times.(b) Probable CauseThe National Transportation Safety Board determines that theprobable cause of this accident was the failure of the flightcrew tomonitor the flight instruments during the final 4 minutes of flight, andto detect an unexpected descent soon enough to prevent impact with theground.Preoccupation with a malfunction of, the nose landing gear - 23 - . 24 - position indicating system distracted the crew’s attention from the / instruments and allowed the descent to go unnoticed.3.As a result of the investigation of this accident, the Safety Boardon April 23,1973, submitted three recommendations (A-73-l 1 through13) to the Administrator of the Federal Aviation Administration: .Copies of the recommendation letter and the Administrator’s response thereto \ are included in Appendix H. . . Recommendations concerning the crash survival aspects of thisaccident have been combined with those of two other recent accidentsand were submitted to the FAA on June 15, 1973. (See Appendix I...) The Board further recommends that the Federal AviationAdministration:Review the ARTS III program for the possible develop-ment of procedures to aid flightcrews when marked deviationsin altitude are noticed by an Air Traffic Controller. (Recom- mendation A-73-46. )The Board is aware of the present rulemaking proceedings initiatedby the Flight Standards Service on April 18 concerning the re

36 quired in-stallation of Ground Proximity
quired in-stallation of Ground Proximity Warning Devices. I-lowever, in view ofthis accident and of previous recommendations on this subject made by .this Board, we urge that the Federal Aviation -4dministration expediteits rulemaking proceedings. - 25 - -BY THE NATIONAL TRANSPORTATION SAFETY BOARDJune 14, 1973 IS/ JOHN H. REEDChairmanFRANCIS H. McADAMS LOUIS M. THAYERISABEL A. BURGESSMembeWILLIAM R. HALEYMembe - 26 - APPENDIX AINVESTIGATION AND HEARINGThe National Transportation Safety Board received notification ofthe accident at 0025 eastern standard time on December 30, 1972, fromthe Federal Aviation Admin An investigation team was dis-patched immediately to the scene.Investigative groups were establishedfor Operations,Air Traffic Control, Witnesses, LVeather, Human Factors,Powerplants, Systems, Flight Data Recorder, and CockpitVoice Recorder.An Aircraft Performance Group was formed at theLockheed-California Company’s flight test facility in Palmdale, California.The Federal Aviation Administration, Eastern Air Lines, Lockheed- California Company,Rolls-Royce (1971) Limited, the Air Line PilotsAssociation,and the Air Line Stewards and Stewardesses Associationparticipated and assisted the Board in this investigation.2.A public hearing was held at the Miami Springs Villas, Miami r Springs, Florida, March 5 through March 9, 1973. Federal Aviation I .- --.-- Administration, Eastern Air Lines, Inc. , Lockheed-California Com- pany; -Air-Line Pilots Association,‘and the Aviation Consumer Action i Project were parties to the he

37 aring.3.Preliminary ReportA preliminary
aring.3.Preliminary ReportA preliminary report of the investigation was released by theSafety Board on January-l 1, 1973. I :d 27 - APPENDIX BAIRMAN INFORMATIONCaptain Robert A.Loft, aged 55, was employed by Eastern AirLines on September 20, 1940.He received his Airline TransportRating on July 15,1942, and was promoted to captain on February 8,1951.Captain Loft qualified for the DC-8 on March 13, 1969. Hecompleted his L-1011 simulator check on April 20, 1972, and his air-craft flight check on June 7, 1972.Both checks were observed by anFAA inspector. Captain Loft’ground school instructor rated himsatisfactory for the entire 8 days of his L-1011 training.Captain Loftreceived 2 hours and 30 minutes of flight training in the L- 1011 air- He completed his rating ride in 1 hour and 30 minutes. Hisinitial line check was completed on July 1, 1972.The officer givingthe flight check stated, in part, in his comments, “Good knowledgeof aircraft and procedures. ” Captain Loft’s last first-class medicalcertificate was issued on November 21,1972, with the limitation that“The holder shall possess correcting glasses for near vision. ” First Officer Albert J. Stockstill, aged 39, was employed byEastern Air Lines on August 7,1959, as a Flight Engineer. He hadprior experience as an Air Force pilot.First Officer Stockstill com-pleted his Second-in-Command training in the DC-8 on December 13,1971.He began his L-1011 training on March 6, 1972. He completedhis oral check on hfarch 15,1972, and his transition check on March27, 1972; bo

38 th were satisfactory. On June 1, 1972, h
th were satisfactory. On June 1, 1972, he satisfactorilycompleted his First Officer qualification, which included CategoryIII-A maneuvers.First Officer Stockstill’s last first-class medicalcertificate was issued on April 11,1972, with no limitations.Second Officer Donald A. Repo, aged 51, was employed by EasternAir Lines on September 11,1947, as an aircraft mechanic prior toattendance at an Eastern Air Lines flight engineer school.On November19, 1955, he qualified for his Flight Engineer Certificate, and on April13, 1967, he qualified for his Commercial Piiot Certificate, with airplanesingle-engine land and instrument privileges.He began his L-1011training on September 18, 1972.He completed his oral examination onSeptember 29,1972, and his simulator check on October 5, 1972. OnOctober 3, 1972, he received a l-l/2 hour walk around of L-1011, N3 1 OEA. On October 7, 1972, Second Officer Repo completed his - 28 - APPENDIX Baircraft check, which included the emergency and abnormal proce-dures associated with the hydraulic systems and the ‘landing gear.On December 19, 1972, he completed his line check. His lastsecond-class medical certificate was issued on August 10, 1972,with the limitation that “The holder shall possess correcting glassesfor near vision. ” The following is a listing of pertinent flightcrew information:Item Date of birth 3/17/17 Time L-1011Total timeCertificatesHours flown24 hrs. priorthis flightHours flownthis flightCapt. LoftF/O StockstillS/O Repo 39 280 hrs.306 hrs.53 hrs,29, 700 hrs.AT5,800 hrs.ATR & FE

39 15, 700 hrs.FE, A&P & 38 ATR-131187FE-
15, 700 hrs.FE, A&P & 38 ATR-131187FE- 1547248FE-175258Comm. -13278A&P-291 795 AMEL, DC-3-4, AMEL, DC-36, 7, 8, M202,Comm. Priv.404, L-49,ASEL. FE - DC-7, L-188Comm. Priv.ASEL k Inst.FE - Recip. Turbo Prop gi Turbo Jet 2:25 Item -LoftF/O StockstillS/O Repo - 29 - Duty timelast 24 hrs. 9:52 ;.; B 9:52 ; . .prior toaccident All 10 flight attendants were qualified.in with existingregulations. . - 30 - APPENDIX CAIRCRAFT HISTORYAircraft N310EA, a Lockheed L-1011-385-1, serial NO. N193A- 1011, was operated by Eastern Air Lines, Inc., and registered to theManufacturers National Bank of Detroit, Michigan. It was receivedby Eastern Air Lines on August 18,1972, and placed into scheduledservice on August 21, 1972.At the time of the accident, it had accu-mulated 986 hours and 502 landings.Scheduled maintenance wasaccomplished by “A” (line) and “C” (major) phase checks.The air-craft had accumulated 132 hours and 69 landings since the last “C” check and 19 hours and 10 landings since the last “A” check.The aircraft was equipped with three Rolls-Royce, RB 21 l-22C, engines .Engine serial numbers and times were as follows:Engine F 1 ight Hours SinceCycles SinceLocation InstalledNumber HoursInstalled 407 104The weight and balance manifest for this flight indicated that theaircraft was within its weight and balance limitations both at takeoffand at the time of the accident.There were 85, 000 pounds of fuel aboard the aircraft upon departurefrom New York.The planned fuel burn-off for the flig

40 ht to Miami was42, 000 pounds.From Octob
ht to Miami was42, 000 pounds.From October 17, 1972, to November 14,1972, N310EA was usedfor the installation and testing of modified Fault Isolation kfonitoring equipment under operating conditions.Fault Isolation Monitoringis the system used on the L-101 1 aircraft’s Avionic Flight ControlSystem to identify detected faults within the autopilot system.A com-plete set of modified AFCS computers was installed in t’ne aircraft onOctober 29, 1972, to evaluate the revised FM circuitry. On November14, 1972, the modified FM equipment was removed, and the originalAFCS computers were reinstalled in the aircraft. - 31 -, APPENDIX C Company records indicated that N310EA had been maintainedin accordance with colnpany procedures and with FAA requirements. . . Investigation revealed that N310EA was equipped with mismatchedautopilot pitch computers.The “A” system pitch computer would re-vert from altitude hold to control wheel steering with only 15 poundsofpitch pressure on either control wheel.’ The “B” system, however,would not revert until it sensed 20 pounds.of pressure.On July 15,1972, Lockheed Serv!ce Bulletin No.093-22-012 (nonmandatory-) wasissued, calling for the modification of pitch computers, which changedthe 20-pound release value to a 15-pound release value. ‘ . . . . . , . . L _. ‘ : -. ” . . . . .-. ,;, ; . . . _ ;. :, e. ., i . : ji . . . . -;- i 4 -;,:,: j : .+ : ’ “

41 6; b . . . ., ., ::-,.:
6; b . . . ., ., ::-,.: :; : - -.. . ,.,,,, : . . . . . . :- i:. : :.I ., ‘ . . / ._: 41.. i ; ‘ :. ! !I _ . I ._ I _! ! ! / . . j I . ._. . . ” .,.._ \.e; ri--. I - -...--- - INTtRNATlONAL AIRPORT 18. I piecer of leit-hand Wing, outer structure. Smell Fngine parts-? fan hlot!e:, Oil cooler. Engine mount frame. port of No. I fan case, oil ccavengs filter.No. 1 Pylon upper :upport structure and front beam fittings.Section of left-hand wing tip.Section of left horironttil rlobilizsr leading edge. a! ft. ,ection of kft e~evarOr panel. nose cowl-upper half. debris Irun gollrv, cabin interior and cargo compts. hotstream spoiler section.Section cl lcfchond wing upper surface.Section of left-hand wing, No. 1 engine.Portion of No. I thrurt rtivurter cupport ring.Now landing oeor strut osrembly. wing ports- in and around crater. Section of Cabin f!ow with 4 first closr seats. of cobin and right-hwd wing.:I. No. 3 Engine. E Z?. Forward Fureloge inc!udinC flight stotion. Aft Fwuloge, No. 2 Engine ond remains of Empennogo. Section of Furel4go-galley area. -m _.. _j ___... -. . ..-_ .-- ~. . _.. _._ -. __ _ - . . . FLIGHT PATH FLT. 401 $ ._.____ -.. _ ._.. _,._-._C- ..- .-: __ . .-- APPENDIX G 38 - ASSESSMENT SIJ~PURY t sl 27 min. Descent toto9700 feet20.6 min. al

42 titude OFI 20.6 min. Altitude Cap- ture
titude OFI 20.6 min. Altitude Cap- ture at 970019.3 min. feet altitude19.3 min. Level flighttoat 9700 feet X16.3 min. altitude420 sec.Level out atto2000 feet n” sec.altitude373 sec.Period beforeto lot # 355 sec.engage order355 sec.Period after t0 autopilot en- 278 sec.gage order;left turnwith 12O roll angle270 sec.Acquire head - ing of 270° 220 sec.220 sec. None - 140 set 140 sec. Pitch overtoand descent20 sec.20 to 0Left turnsec.toward 180 X s e c. *pre . / . THE X DENOTES THE NODE ENGAGED AS INDICATED BY THE PERFORUKE A'JALYSIS.THE * DESOTES EITHER OF TWO MODES IKDICATED. TEE # DEWTES POSSIBLE PIODES WHEN MORE THU TN0 ARE POSSIBLE. -39-APPENDIX H UNITED STATES OF AMERICANATIONAL TRANSPORTATION SAFETY BOARDWASHINGTON, D.C. ISSUED: Nay 2, 1973 Adopted by the NATIONAL TRANSPORTATION SAFETY BOARD at its office in Washington, D. C.on the11th day of April - - - - - - - - FORWARDED TO: 1 Honorable Alexander P. Butterfield ) Federal Aviation Administration Washington, D. C. 20591 SAFETY .RECOMMENDAT IONS A-73-11 thru 13 '\I. The National Transportation Safety Board's current investigation ofa fatal air carrier accident involving an Eastern Air Lines, Inc., L-1011, h310EA, which crashed near Miami, Florida, on December 29, 1972, has revealed two areas in which we believe early corrective action is neededto prevent the recurrence of similar accidents. The involved crashed about 6 minutes afterthe crew kad executed a missed agrcach in order to check the status of the nose gear. The g

43 reen, gear-safe annunciator lighthad fai
reen, gear-safe annunciator lighthad failed to illuminate when thegear handle was placed in the gear-dab-n position during the initial approach. Our investigation indicates that at the.tise of the acci,dent, all three flight crewmem*oers were engrossed in an attempt to ascertain whether the landing gear k-as safely extended, and they were not aware until just before impact that the airplane had departed the 2,000-foot clearance alti- tude. flight engineer was in the fomard avionics center, locatedbeneath the cockgis and just forward of the nose whtelvell, attempting to ascertain visually, by means of an cptical sighttube, whether the gear wzs locked down. The flight engineer was notsuccessful in his attempt to vie-~ the rods on the nose lending gear linlcage which indicate whether the gear is loclied this is to be done at nig'nt, a light in tk2 noti2 vheell.Jell must be turne,:! on by a s-ditch on the captain's eyebrow panel. who attempts to vies; the indica';or rods must pull a knob located ov2r an optical sight in order to remove a cover on the far end of the sight,. C'SO, flight engineer twice noted that.he cculd see nothing -- t-hat it was "pitch dark." Wa do rr,t !ir?ow whether (1) the czgtair. 2v2r attef?ced APPENDIX H Honorable Alexander P. Butterfield _ 40 - to turn on the light (the crew seemed to think that the light should bs on whensv2rthe landing gear was extended), (2) the light vas inoperative,or (3) the flight engineer properly operated the knob wh

44 ich removes the optical t*ube cover. I
ich removes the optical t*ube cover. In any event,the Safety Board believes that this unsuccessful attempt to ascertain wha' the nose landing gear was lockeddown contributed to the distraction cf the flightcrex during this flight. For this reason,the Safety Board believes that this system should be oper-able by one man; therefore, the switch for the wheelwell light should belocated near the optical sight. Furthermore, a placard outlining the proper use of the systen should be installed near the light sxitch and the knob for the optical sight cover. Th2 reason for the descent from an altitude of nearly 2,930 feet has not yet been d-etermined. The cockpit voice recorder (03) indicates, how- everthat the altitude select, alert system sounded shortly after the initial descint.. This alert system is comprised of a single C-chord and a flashing pznber alert light. When the airplane departs the selected altitude by + 250 feet, the C-chcrd soiL'ds once, and the amber light flashes continuously. * on the Eastern Air Lines configuration, this light is inhibited from operating below 2,503 feet radar altitude. Thus, cr. the accident air- plane,the only altitudealert system warning to the crew that the airplane h-as descending x'as the single C-chord. There is no evidence on the 0T.R to indicate that the crew ever heard the audible warnirig as the airplane main- tained a continuous descent into the ground. Therefore, the Safety Board reco-mmends that the Federal Aviation Administration: Require theinstallation of a switch for

45 the L-1011 nose wheel~ell light near t
the L-1011 nose wheel~ell light near the nose gear indicator optical sight. \ near the optical sight, the installation of A placard which explains the use of the system. \ Require that the altitude select alert light system onEastern Air Lines-configured L-1011 airplanes be modified to pro*Jidt a flashing light warning to the crew whenever an airplane departs any seleL~- fttt, operations below 2,5*G;'J feet radar altit:-Ze. of cur Bureau of Pviaticn Safety Ml1 be available for ccn- in the 250~2 rrattzr if desired. Honorable Alexander P. Butterfield -41- APPENDIX H ; These .recommendations will be released to the public on the issue date shown above. No public disseriiination of the conterits of this docuent should be made prior to that date. ._ . . Reed, Chairman; McAdams, Thayer, Burgess, and Haley, Members,concurred in the above recomendations. APPENDIX H - 42 - DEPARTMENT OF TRANSPORTATIONFEDERAL AVIATION ADMINISTRATIONMay 14, 1973WASHINGTON. D.C. 2059i) Honorable John H. Reed Chairman, National Transportation Safety BoardDepartment of TransportationWashington, D. C.Dear Mr. Chairman:This replies to your Safety Recommendation A-73-11 thru 13issued May 2, 1973, concerningmodifications to preclude therecurrence of an accident such as the Eastern Air Lines, Inc.,L-1011, N3lOEA, which crashed near Miami, Florida, onDecember 29, 1972.We are studyingthe recommendations and will advise what actionswill be taken as soon as our evaluation is completed.Sincerely,. Acting Administrator OFFICE OF THE ADMIHI

46 STRATL -43 - APPENDIX I UNITED STATE
STRATL -43 - APPENDIX I UNITED STATES OF AMERICA NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. June 25, 1973Adopted by the EiATIONAL TRANSPORTATION SAFETY BOARDat its office in Washington, D. C. on the 6thday of June 1973 FORWARDED TO: 1 Honorable Alexander P. ButterfieldAdministrator Federal Aviation Administration ) Washington, D. C. ‘SAFETY RECOMMENDATIONS A-73-39 thru 43 Transportation Safety Board has under investigation,three accidents involving:a United Air LinesBoeing 737 at Nidk-ay Airport, Chicago, Illinois, on December 8, 1972; a North CentraAirlines DC-g, at O’Hare International Airport, also at Chicago,Illinois, on December 20, 1972; and an Eastern Air Lines LockheedL-1011 at Miami, Florida, on December 29, 1972.The Safety Board has identified several areas in occupant sur-vival and evacuation common to these accidents which it believes meritremedial action by the Federal Aviation Administration.These areasare delineated below:Shoulder Harness Restraint.Testimony at the Safety Board’s public’hearing concerning the United B-737 accident revealed that crew takeoffand before-landing checklists did not contain the item “Shoulder harness Fas t ened. ” The injurie sustained by the captain, as well as the con-ditions of the captain’s and first officer’s shoulder harness in theindicated that the shoulder harness had not been used.In the EAL accident,we noted that the shoulder harness on the aft facing cabin attendant seats had been removed,In a letter dated p!arch

47 12, 1973, the Board,in commenting on you
12, 1973, the Board,in commenting on your Notice of ProposedRule �Iaking 73-1,expressed its concern about the absence of a require-ment to have shoulder harnessesinstalled on aft facing seats. \de pointed out that in crashes or ener;ency landings involving nultidirec- tional inertia forces,shoulder harnesses vould provide an additional, APPENDIX I -44- and possibly vital,measure of protection for occupants of aft facingThe principal advantage of a shoulder harness, both in fon.;ard and rearxard facing seats,is that it helps to restrain the user inan upright position,thereby keeping the spinal column in a more suit-able position from the standpoint of load distribution,the shoulder harness prevents the upper body from flailing, a frequentcause of serious injuries in aircraft accidents.The Eoard believes . that increased protec.tion from injury of the flightcrew as well as thecabin attendants is of vital importance,since their availability toguide and aid passengers during evacuation may make the differencebetween survival and disaster.the Safety Board recommendsthat the Federal Administration:Take the necessary steps to ensure that all air carrierbefore-landing and takeoff checklists contain a “Shoulder Harnesses” item. 14 CFR 25.785(h) to require provisions for ashoulder harness at each cabin attendant seat, andamend 14 CFR 121.321 to require that shoulder harnessesbe installed at each cabin attendant seat. Portable Lirhtinn. the investigation and public hcar- ing held in connection with the EXL L-1011 accide

48 nt, testimony indicatedchat the absence
nt, testimony indicatedchat the absence of lighting of any kind at the crash scene seriouslyhampered. survivors ’ ability to orient themelves and prcventcd them from searching for and assisting other injured survivors.Additionally, ! lack of light prevented cabin attendants from taking effectivecharge among the surviving passengers.In both Chicago accidents, a i similar lighting problem uas encountered.Although section 121.549(b) of the Federal Aviation Regulations requires each crewmember to haveavailable a flashlight,cabin attendants usually stow their personalflashlights in their handbags, tend to become lost in the debrisof the wreckage.for example,was the case in both ChicagoaccidentsThe Board believes that effective alternate means of light-ing, ? is not dependent on random stowage and location, should bereadily accessible to the flight attendants.Therefore, the Safety Board recommends that the Federal Aviation Administration:3Amend 14 CFR 25.812 to require provisions for the stow- age of a portable, high-intensity light at cabin attend-ant Stations;and amend 14 CFR 121.310 to require theinstallation of such portable, high-intensity lights atcabin attendant stations, V - APPENDIX I Em2rgency Lighting.Evidence obtained during the invastigation of the Elorth Central DC-9 accident and the United B-737 accident in Chicago,indicated that many passengers had difficulties in escaping from thewreckage.These difficulties liere a result of inadequate illumination,combined with a heavy smoke condition in one of these acciden

49 ts. Inthe United accident,survivors spec
ts. Inthe United accident,survivors specifically mentioned the absence ofany light in the cabin.In the Korth Central accident, passengersexperienced great difficulty in locating t exits,.,reportedly becauseof darkness and heavy smoke in the cabin.Yetthe cr2w testifiedthat the emergency lighting system wasarmed, and th2 in.ves tigationindicated that they should have been operational. four ofthe ninefatally injured passengers apparently died :.lhile th2y wereattempting to find an exit.On2 passenger was found in the cockpit,one near the cockpit door, and two others were found near the aft endof the cabin.The five remaining fatalities apparently had not lefttheir seats. rcconunendations and proposals to improvs occupant escapecapabilities in survivable accidents have been made ov2r the years byvarious Government and industry organizations; and, indeed, significantimprovements have occurred.Unfortunately, however, experience indicatesthat the existing escape potential from aircraft in which postcrash fireis involved is still marginal. accidsnts illustrate the vitalrole that adequate illumination can play in contributing to such postcrash review of CFR 25.811 and 25.812 indicates that paragraph 811(c)requires meabs to assist occupants in locating exits in conditions ofdense smoke. Yet, information from’ ths Civil Aerom2dical Institute inOklahoma City indicates that the illumination levels speciEied in para-graph 812 .are not predicated on a smoky environment, and t’nerefore maybe ineffectivs under condi

50 tions of dense smoke.in ord2r to elimi
tions of dense smoke.in ord2r to eliminate is t cncy ,the Board believes that illumination levels shouldb2 specified in paragraph 812,which are consistent with the require-ments of 14 CFR 25.811(c) . Noreover, and other accident experi-ences have shown that for various reasons aircraft emergency lightinsystems often do not work or are proved ineffective in survivable acci-the Safety Board recommends that the Federal AviationAdministrationAmend 14 CFR 25.812to require exit sign brightnessand general illuminstion levels in tiie passengercabin that are corsistent with those necessary toprovide adequate visibility in conditions of d2nse APPENDIX I I : 5. CFR 25.S12 to provide an addition31 means foractivating the main emergency 1iglltin.g syscanr to provide and tl;creby improve its reliability.: Evacuation Prsblcss: recurring problun of galley securitywas enccuntcrcd in the C.AL C-737 accident !.;!IQ~, during impact, food and sarvice items fell f:om the two aft cabir. galley units. , was descrjbcd by cabin att as a series of mild to moderate : jolts acting forward rcarxard, caused thz four oven units and food : co12 food trays, and theliquor supply ur.its to be thru:m to the floor near the rear service door. The Duoard previously hascommented on theevacuation hazard caused by loose galley equipment andacknowledgesa letter from the PA4 dated February 16, 1973, !.:hich cites:corrective actions to ailcvintc the galley security problem. Specifica

51 lly, j_ : are encouraged by recent
lly, j_ : are encouraged by recent amendments to Parts 25 a:ld 121 @f the F2dera.l Aviation Rcoulations , rrhich ccvcr the retention of items of mass inpassenger and crew comp3rtmcnts. xish to reiteratecur belief conccrnin2 ncclil for furt!lcr imp~ovcmcnts to ensure the of galley equlpccnt under crash landi;:,; loads.The Board is aarc that an amendment to lC, GFR 25.789, which :Jould require the instal-lation of SccondJry dctiices on galltiy cquipmcnt, is under car,- sideration for i action.-. In view of the steps that you ha. initiated to remedy this safety problem, the Safety Eoard is not making a formal rccorxcndation at tilis time. I r we urge you to esprdite vour consid?rstion of tilis matter in order t!xtt an amcndcd gallev rcten- regulation can be IKIJC: effective at an early date. This document 5.511 bc rclcased to the public 0:: t!lc t!zt2 SliO!rIT public dissemination of this docbZi~:nt silculd b:~ cad2 prier to that date. APPENDIX I - 46 - Amend 14 CFR 25.812 to provide an additional meads foractivating the main emergency lighting system to provideredundancy and thereby improve its reliability. Evacuation Problems: A recurring problem of galley securitywas enccuntcrcd in the b B-73? accident rihcn, during impact, food andservice items fell from the two aft cabin galley units.The impact, .which was described by cabin attendants as series of mild to moderatejolts acting roar-war

52 d, caused the four oven units and food
d, caused the four oven units and food carriers, cold food trays, and theliquorsupply units to be thrownto the floor near the rear service door. The Board previously hascommented on the evacuation hazard caused by loose galley equipment andacknowledges a letter from tl!e FAA dated February 16, 1973, which citescorrective actions to ailcviatc the galley security problem. we are encouraged by recent amendments to Parts 25 and 121 of the FederalAviation Regulations, which cover the retention of items of mass inpassenger and crew compartments.Naverthclcss, WC to reiterateour belief concerning the need for further improvcmcnts to ensure thesecurity of galley equip,mcnt under crash landing lads. Board is aware that an amendment to 14 6FR 25.789, vilich would rcquirc the ins tal- lation of secondary retention devices on ~allcy equipment, is under COI;- sideration for i action.-- In vice of tllc steps that you hal.,$ to remedy this sa,fcty problem, the Safety Board is not ma:cing a formal rccommcndatiori at ‘ time. Howcvc r , we urge you to expedite‘your consideration of tllis matter in order that an amcndcci galley rcten- tiou regulation can be made cffhctiva at an early date. This document -Gill IJC rclcased to the public 0:: the dats No public clisscninntion of this clcchw1~t should be mJ2 prior ; to that date. ~ccd, Chairman, ~k&lams, Thnycr, and HaIcy, Xcmbcrs, concurred in tile above recommendations. ?!cribar, r..*as