71-2

INCIDENT INVESTIGATION REPORT

-^ OF AIR SflfETY INVESTIGATIONLIBRARY COPY

Boeing 747Aircraft N652 PAat Sydney (Kingsford-Smith) AirportNew South Wales on 18 July 1971

SPECIAL INVESTIGATION REPORT 71-2

Air Safety Investigation Branch

GICIDENT INVESTIGATION REPORT

Department of Civil Aviation

Australia

Pan American World Airways Inc.

Boeing 747Aircraft N652 PAat Sydney (Kingsford-Smith) AirportNew South Wales on 18 July 1971The investigation of this incident wasauthorised by the Director-General ofCivil Aviation pursuant to the powersconferred under Air NavigationRegulation 278.

Prepared by :Air Safety Investigation Branch

July, 1972

©Commonwealth of Australia 1972: The contentsof this publication may not be reproduced in wholeor in part without the written authority of the Depart-ment of Civil Aviation. Enquiries should be addressedto the Air Safety Investigation Branch, Box 1839 Q,G.P.O., Melbourne 3001.

C O N T E N T S

Section 1 INVESTIGATION Page 11.1 History of the Flight 11.2 Injuries to Persons 4.3 Damage to Aircraft 4.4 Other Damage 4.5 Crew Information 5.6 Aircraft Information 5.7 Meteorological Information 5.8 Aids to Navigation 6.9 Communications 6.10 Aerodrome and Ground Facilities 6.11 Flight Recorders 7

Flight Data Recorder 7Cockpit Audio Recorder 7

1.12 Wreckage 81.13 Fire 81.14 Survival Aspects 81.15 Tests and Research 8

Expected Landing Performance 8Evidence from Motion Picture Film 8

Section 2 ANALYSIS 82.1 General 82.2 The Approach to Touchdown 102.3 The Failure to Stop on the Runway 112.4 The Go-around Consideration 12

Section 3 CONCLUSIONS 12

APPENDICESViews of Aircraft and Nose Undercarriage Appendix APlan View of Sydney Airport Runway 25 Appendix BBraking Marks on Runway Appendix CRecorded Flight Data During Approach Appendix D

and LandingFinal Approach Profile and Touchdown Point Appendix EApproach Height Effect Appendix FTranscript of Cockpit Audio Recording Appendix GThree Degree Approach Slope Runway 25 Appendix HLanding Performance Chart Appendix I

THE INCIDENT

At approximately 0912 hours EasternStandard Time (EST) on 18 July, 1971, theBoeing 747 aircraft, registered N652PA, over-ran the end of Runway 25 and became boggedin soft earth whilst landing at Sydney (Kings-ford-Smith) Airport, New South Wales. Theaircraft was engaged in operating Pan AmericanAirways Flight 811, a regular public transportservice from Los Angeles to Sydney with inter-mediate stops at Honolulu and Nadi. Theaircraft sustained no damage and none of the15 crew members or 269 passengers on boardwas injured.

1 — Investigation

1.1 HISTORY OF THE FLIGHT

At 0506 hours EST on 18 July 1971 PanAmerican Airways Flight 811, radio call signClipper 811, departed from Nadi for the flightto Sydney. A crew change had occurred atNadi and the aircraft was now under the com-mand of Captain W. A. Thomas. The otherflight crew comprised First Officer N. S.Simpson and Flight Engineer H. C. Schmidt.Captain Thomas occupied the left-hand controlseat and operated the flight controls on thisroute sector.

At 0844 hours, following an uneventfulflight from Nadi, Clipper 811 advised SydneyArrivals Control that it was over the position-reporting point "Thresher" at Flight Level 350and had received the Automatic TerminalInformation Service (ATIS) broadcast, "Echo"(for details refer to Section 1.7). At 0848 hours,having been cleared to commence descent,Clipper 811 reported leaving Flight Level 350and was advised by Arrivals Control that itwould be making a straight-in approach toland on Runway 25.

At that time another Pan American Air-ways Flight, a Boeing 707 aircraft with thecall sign CLIPPER 812, was approachingSydney from the west and, in accordance withthe Sydney noise abatement procedures, wasbeing processed by Arrivals Control for astraight-in approach to land on Runway 07.

The programmed landing time for CLIPPER811 was several minutes prior to that ofCLIPPER 812 and, to achieve this landingorder, it became apparent to Arrivals Controlthat speed control of both aircraft would benecessary.

The noise abatement procedures applicableto arriving aircraft during the period of theday from 0645 to 1900 hours, specify thatpilots should expect to land on the runwaywhich most nearly affords a straight-inapproach and air traffic control procedures willbe applied to achieve this preferred procedure,having due regard to safety, wind and weatherconditions.

At 0903:13 hours Sydney Approach Con-trol instructed CLIPPER 811, which hadtransferred from Arrivals Control two minutesearlier, to "maintain" as fast a speed as possiblefor as long as possible". CLIPPER 811replied "OK we're out of six for five, we'llmaintain 250 knots."

At 0904:25 hours Approach Control in-structed CLIPPER 811 to descend to 3,000 feetand to report when visual. CLIPPER 811acknowledged this instruction and advised thatthe aircraft was then leaving 5,000 feet.

At 0905:12 hours, CLIPPER 811, notifiedthat it was then reducing speed and the air-craft was instructed to descend to 2,000 feet.

At 0906:11 hours, CLIPPER 811 reportedthat the aerodrome was in sight. SydneyApproach instructed it to make a visualapproach, straight-in and to call Sydney Toweron 120.5 MHz at 10 miles.

Meanwhile CLIPPER 812, which firstreported to Approach Control at 0903:42 hours,on reaching a position 30 miles from Sydney,was given progressive descent instructions andspeed reductions in order that the preferredstraight-in approach for Runway 07 could becontinued.

At 0907:24 hours CLIPPER 812 wasinstructed to descend to 3,000 feet and at0907:32 hours the approach controller askedthe aerodrome controller to advise him whenCLIPPER 811 was assured of a landing so thatfurther descent for CLIPPER 812 could beauthorised.

At 0907.35 hours CLIPPER 811 reportedat 10 miles on the aerodrome control frequency.

The aerodrome controller instructed CLIPPER811 to report on short final but, at 0908:37hours, before CLIPPER 811 had given thisreport, the aerodrome controller cleared theaircraft to land.

At 0908:53 hours, Approach Control toldCLIPPER 812 "you will be number two toland, the number one aircraft is a 747 on fivemile final for Runway 25, can you reduce anyfurther?" CLIPPER 812 agreed to furtherreduce speed and at 0911:14 hours ApproachControl instructed the aircraft to descend to2,500 feet, which would still provide a safevertical separation from CLIPPER 811 in theevent of that aircraft making a missedapproach.

At 0911:20 hours the approach controlleragain asked the aerodrome controller for adviceon CLIPPER 811's progress and was told"advise in one!"

The aerodrome controller has stated thatCLIPPER 811 appeared to be high during itsfinal approach. He observed the aircraft touchdown at approximately the intersection of therunways. At 0911:50 hours, when he was surethat the aircraft would not go around, he toldthe approach controller "he's down" andadded at 0911:58 hours, "he got down at theintersection".

When the approach controller receivedthe advice that CLIPPER 811 had landed (onRunway 25) he instructed CLIPPER 812 tomake a visual approach straight-in (for Run-way 07) and to call Tower on frequency 120.5MHz.

The senior tower controller has statedthat CLIPPER 811 crossed the threshold ofRunway 25 at a height he estimated to beabout 200 feet. The aircraft then levelled andappeared to float losing height slowly andpassed the junction of Taxiway 'N' (seeAppendix B). It appeared to him, at this point,that a go-around was imminent but the aircraftcontinued the approach and the main wheelstouched down at the intersection of the run-ways with the aircraft in a nose^igh attitude.He has also stated that the nosewheels toucheddown abeam of Taxiway ']' with the enginesdelivering reverse thrust. He observed whatappeared to him to be a compressor stall inNo. 3 engine and immediately, at 0912:04hours, he alerted the airport fire service watch

room on a direct inter-communication line —"Will you watch that Jumbo please . . . flamein number 3!"

At 0912:05 hours CLIPPER 812, which wasapproaching to land on Runway 07 made itsfirst call on the aerodrome control frequencyand reported — "SYDNEY TOWER, CLIPPER812 about a four mile final". The aerodromecontroller who was watching the landing runof CLIPPER 811, did not reply to this call.

The senior tower controller has statedthat, whilst water spray and smoke envelopedthe aircraft, it was difficult to see from theTower whether or not CLIPPER 811 had runoff the end of the runway but, at 0912:13 hours,he is recorded as saying, on the direct line tothe airport fire service — "HIT! HIT IT!YES!" indicating a need to sound the crashalarm and, at the same time, he activated thecombined crash call facility to alert the civilemergency services.

The surface movement controller inSydney Tower has stated that he first observedCLIPPER 811 whilst it was still some distanceout on final approach. His attention was nextattracted to that aircraft when the senior towercontroller commented that CLIPPER 811appeared to be high. Although, to him, theaircraft did not appear particularly high atthat time, he estimated it to be about threemiles from the aerodrome. Its excessive heightbecame apparent, however, as the approachcontinued and he estimated that the aircraftwas at a height of between 150 and 200 feetwhen it crossed the threshold of the runway.He has stated that the aircraft continued itsdescent to about the junction with Taxiway'N' where it appeared to commence a flare.The aircraft then appeared to float and passedabeam of the Tower position with the mainbody of aircraft at about his eye level. Duringthis period of high float, which persisted toabout the junction with Taxiway 'L', he hadthe impression that the aircraft was preparingto go-around. Beyond Taxiway 'L' he saw theaircraft commence to sink until the initialtouchdown was made by the rear wheels ofthe outboard bogies just prior to reaching theintersection of the two runways.

The aircraft continued in a nose highattitude to the junction with Taxiway 'J' whereit appeared to the surface movement controllerthat reverse thrust was applied before the

nosewheels actually touched down on therunway. He heard and observed what appearedto be a compressor stall in No. 3 engine whenthe aircraft was in the vicinity of the touchdownmarkings for Runway 07. Although the air-craft was three parts obscured by spray theflash from that engine was easily discernible.He had the impression, looking through thespray cloud, that the aircraft was commencinga turn into Taxiway 'C' at a slightly higherspeed than normal but, when the aircraftstopped suddenly and the nose and left wingtilted down, he believed that it had left thepaved surface and he immediately sounded thecrash alarm.

A fireman on duty at the Airport FireStation adjacent to the Control Tower alsoobserved the approach and landing of CLIPPER811. When he saw the aircraft flying above therunway in a tail down attitude and noticedthat it did not touch down before reachingTaxiway 'L' he immediately alerted the DutyFire Officer. The Duty Fire Officer, observingthat the nosewheels were still not in contactwith the runway at the intersection of therunways, ordered the fire crew to stand bytheir appliances in anticipation of an abnormallanding turn out.

The fireman on duty in the watchroom,which is an observation tower located on topof the Airport Fire Station, was monitoring theaerodrome control frequency. He has statedthat he heard CLIPPER 811 call on thatfrequency and observed the approach andlanding of the aircraft. The aircraft appearedto be high on final approach but he could notestimate its height when it crossed the runwaythreshold. When the aircraft passed abeam ofhis position in the watchroom tower, the bottomof the fuselage appeared to be at his eye level(i.e. about 20 feet). He saw the aircraft's mainwheels first touch down at about Taxiway 'L'in a nose high attitude which was maintainedto the runway intersection or shortly thereafter.He observed a large sheet of flame appearfrom the No. 3 engine when the aircraft wasbetween Taxiways 'V and ']'. At the sametime the Tower phoned him on a direct lineto draw his attention to this occurrence. Henoticed the spray which enveloped the aircraftfrom about Taxiway 'J' and recalls that,immediately after this, the Tower called himagain. Although he could not remember thewords used, the urgency of the voice indicated

that the aircraft was in difficulties. He soundedthe crash alarm and turned out all appliancesto the threshold of Runway 07.

It is apparent that this fireman and thesurface movement controller activated thecrash alarm facility, simultaneously, im-mediately following the alert given by thesenior tower controller at 0912:13 hours.

The aerodrome controller has stated that,after touchdown, he continued to watch thelanding run of CLIPPER 811 and, as itapproached the end of the runway, he sawthe aircraft suddenly "skew to the right". Thecrash alarm then sounded.

At 0912:19 hours the aerodrome controlleradvised the approach controller that CLIPPER812 would be making a missed approach,obtained a clearance for that aircraft andinstructed it to transfer back to the ApproachControl frequency.

At the time of this incident an airportsafety officer was carrying out an inspectionof the manoeuvring area for the presence ofbirds. His vehicle was equipped with a radiotransceiver operating on the surface movementcontrol frequency. He had positioned his vehicleon the grassed area between Runway 16 andTaxiway 'V just outside the southern edgeof the Runway 25 flight strip and he wasfacing towards the Tower (see Appendix B).

The safety officer has stated that he alsoobserved the approach and landing of theBoeing 747 aircraft from a time shortly afterthe surface movement controller notified thatthe aircraft was on a ten mile final. Thisnotification was recorded at 0907:39 hours. Thesafety officer says that the aircraft appearedto be higher than normal over the runwaythreshold and did not touch down until it wasat a position between Taxiway 'L' and Runway16. The landing appeared to be smooth andthe aircraft did not bounce. The rear wheelsof the main gear touched down before the frontwheels and the nosewheels remained clear ofthe runway for some distance. When he sawthe aircraft land so far down the runway heanticipated trouble and turned his vehicle aboutand followed the aircraft to the western end.He did not see the position at which thenosewheels first touched down as he wasengaged in turning his vehicle at that time.

A few seconds after he observed the aircraftcome to rest off the end of the runway and

before he could alert the Tower of the situation,he heard the crash alarm sound.

The safety officer proceeded immediatelyto the aircraft and, at 0913:22 hours, notifiedthe Tower that there was no sign of fire andthat the aircraft only appeared to be bogged.After the airport fire service appliances arrivedat the aircraft, the safety officer returned to therunway and marked the position at which heobserved the aircraft first touch down.

An examination of tyre marks on therunway indicate that the aircraft first madecontact with the starboard body gear truck ata position close to the runway centre-line and4,003 feet beyond the landing threshold. Theaircraft then travelled a distance of some 1,945feet before the nosewheel touchdown occurred.The first identifiable tyre marks associated withheavy braking appeared at a point shortly afternosewheel touchdown and they continued fora distance of 1,714 feet to the end of the run-way as well as across a further 200 feet ofsealed low strength pavement. Whilst crossingthe low strength pavement the aircraft turnedto the right through some 37 degrees from therunway alignment. As the aircraft left thesealed area it entered soft sandy soil and cameto rest with the 16 main wheels bogged tovarying depths up to 2 feet. The nosewheelassembly was buried to the level of the steeringcylinders at a point 325 feet beyond the endof the runway proper (see Appendix C).

The captain has stated that the approachand landing were normal and that flap position30 was used. He states that he was usinga normal 2,000 foot aiming point and touch-down occurred shortly after passing Taxiway'N' (i.e. at a point approximately 1,800 feetbeyond the runway threshold). The targetapproach speed computed on the flight deckwas 140 knots and the first officer called aspeed of 144 knots just prior to the landingflare. The captain further stated that theapproach slope closely approximated threedegrees and that the threshold crossing heightwas normal for a visual approach. He did notuse the T-VASIS system which was operatingnor did he ask for the RED-WHITE VASIS,which was available on request.

The captain has also stated that, aftertouchdown, he immediately selected speedbrakes and commenced the application of ful l

reverse thrust from Nos. 2 and 3 engines atthe same time applying wheel braking to putthe nosewheel on the runway, after which fullwheel braking was applied. The No. 1 enginethrust reverser was placarded "INOPERA-TIVE" and the captain elected not to usereverse thrust on either this engine or the No.4 engine.

The captain has said that there was notany malfunction of the braking system andhe believes that the anti-skid system operatednormally. He has stated that he did not getnormal deceleration, that he felt frequentbrake releases and that he believed that thiswas due to the wet and slippery condition ofthe runway. As the aircraft neared the end ofthe runway, it was steered to the right off theend of the sealed surface to avoid runninginto a large concrete sewage outfall and asunken perimeter road just off the end of therunway.

The first officer's evidence confirmed thatprovided by the captain and he further statedthat, about one hour after the incident, thecrew went back along the runway and examinedit. There had been no rain since the incidentand this examination revealed that the runwaywas wet and that there were scattered puddlesof water up to 3/8 of an inch deep in depres-sions in the runway surface.

The flight engineer did not detect anymalfunction of the anti-skid system during thelanding roll, and after the aircraft had stopped,he satisfied himself that the system operatednormally. At the same time a check of thebrake temperatures revealed them to be in thenormal or slightly below normal heat range.

1.2 INJURIES TO PERSONS

None of the occupants of the aircraft wasinjured.

1.3 DAMAGE TO AIRCRAFT

There was no damage to the aircraft, butboth nosewheels were changed as a precautionagainst possible contamination by the sand inwhich they were buried.

1.4 OTHER DAMAGE

There was no other damage.

1.5 CREW INFORMATION

Captain William Ashbridge Thomas, aged52 years, was the holder of an airline transportpilot certificate and a current first class medicalcertificate. He was authorised to fly Boeing747 aircraft and had accumulated 532 hourson the type. His total flying experienceamounted to 26,055 hours. Captain Thomassaid that he had landed a Boeing 747 aircraftat Sydney on one previous occasion somemonths prior to this incident but that landingwas not on Runway 25.

First Officer Norman Sidney Simpson,aged 40 years, was the holder of an airlinetransport pilot certificate and a current firstclass medical certificate. He was authorised tofly Boeing 747 aircraft and had accumulated730 hours on the type. His total 'flyingexperience amounted to 11,990 hours.

Flight Engineer Harold Charles Schmidt,aged 54 years, was the holder of a flightengineer certificate and a current second classmedical certificate. He was authorised to actas flight engineer in Boeing 747 aircraft andhad accumulated 690 hours on the type. Histotal flying experience amounted to 27,947hours.

1.6 AIRCRAFT INFORMATION

The aircraft, a Boeing 747, was construc-ted in the United States of America in 1970and had been owned and operated solely byPan American World Airways Inc. sincemanufacture.

It had flown a total of 886 hours sincenew and, with the one exception mentionedhereunder, there was no evidence in the air-craft records of any engineering deficiencywhich could have been relevant to this incident.The No. 1 engine thrust reverser, was placar-ded "INOPERATIVE" because the turbinethrust reversing element had been renderedinoperative by the maintenance staff but thepilot was able to use both the turbine andfan thrust reversers on the two inboard engines.Nevertheless, the effect of reverse thrust is nottaken into account in determining the requiredlanding distance and the FAA approvedminimum equipment list permits both turbineand fan thrust reversers on the outboardengines to be inoperative without any additionto the required landing distance.

The maximum permissible gross weightsfor this aircraft, having regard to structuralconsiderations only are 710,600 Ib for take-offand 564,000 Ib for landing. The anticipatedfuel burn-off during this flight to Sydney was110,400 Ib which limited the maximum grosstake-off weight at Nadi to 674,400 Ib. Theactual gross take-off weight at Nadi was590,935 Ib and the landing weight at Sydneywas estimated to be 480,535 Ib. The loadingcalculations also show that the aircraft's centreof gravity would have remained within safelimits during the whole of the flight. At thecommencement of the descent the flightengineer calculated the landing weight to be484,000 Ib and this figure was used to computethe target approach speed.

The target approach speed used by PanAmerican Airways is termed the programmedspeed (V prog). This speed is derived from abasic threshold speed (Vth) specified in theflight manual for the landing gross weightand the aircraft configuration. The Vth onthis occasion was 130 knots. There was noadjustment required for wind gradient or gustsbut the maximum permissible optional perfor-mance adjustment of 10 knots was added tothe Vth, giving a target approach speed or Vprog of 140 knots. Using the landing weightcomputed at the commencement of the descent,the existing conditions of surface wind, the flapsetting, the runway pressure altitude and anadditional 15% margin for wet runway surface,the required landing field length specified inthe flight manual is 6,900 feet. The availablelength for landing on Runway 25 is 7,898 feet.

1.7 METEOROLOGICAL INFORMATION

Route and aerodrome weather forecastsprepared by the Sydney Area MeteorologicalOffice are distributed on a routine basis to theNadi Meteorological Office. The aerodromeweather forecast for Sydney covering theestimated time of arrival at Sydney of CLIPPER811 was prepared at 2205 hours on 17 July.The forecast was valid for the period 0001 to1200 hours, 18 July, 1971 and specified a windvelocity of 320 degrees at 5 knots; visibility 20miles and 4/8 strato-cumulus cloud at 4,000feet. It was also forecast that, during the period0800-1000 hours, the wind direction wouldback to 290 degrees with the wind speedincreasing to 12 knots and the cloud amount

would decrease to 3/8 cover. The crew ofCLIPPER 811 received a copy of this forecastfrom the Meteorological Office, before departingfrom Nadi.

The routine aerodrome weather reportprepared by the Sydney Meteorological Officeobserver at 0855 hours on 18 July, 1971recorded a wind velocity of 280 degrees at 5knots, visibility 30 nautical miles, 1/8 strato-cumulus cloud at 2,500 feet and 5/8 strato-cumulus cloud at 6,000 feet. The only changesappearing in the next routine aerodrome reportat 0925 hours were in respect of wind velocitywhich had altered to 260 degrees at 8 knotsand the total cloud cover to 5/8 strato-cumulusat 5,000 feet.

Routine broadcasts of selected meteoro-logical information for use by aircraft in flightare made by Sydney Flight Service commencingon the hour and half hour. These broadcasts,designated VOLMET, are not recorded but itis probable that the amended Sydney aero-drome forecast, issued at 0527 hours on 18July, 1971 was first included in the VOLMETBroadcast made at 0530 hours. This amendedforecast, which was valid for the period 0600to 1800 hours specified a wind velocity of 230degrees at 12 knots, visibility 10 nautical miles,rain, 8/8 strato-cumulus cloud at 4,000 feetand 2/8 stratus cloud at 1,200 feet. It wasfurther forecast that, gradually, between 1200and 1400 hours, the wind direction would backto 200 degrees with a speed of 10 knots andthe cloud cover would become 4/8 strato-cumulus at 5,000 feet.

The aerodrome controller, located inSydney Tower, continually observes the existingweather conditions for the purpose of providinginformation to aircraft landing and taking-off.The observed weather conditions, together withpertinent aerodrome and operational infor-mation are contained in the Automatic Ter-minal Information Service (ATIS) broadcaston the Sydney VOR and NDB frequencies.The ATIS designated "ECHO" which wascurrent until 0844 hours on 18 July, 1971specified:

"Runway 16 for departures, runways16 or 07 for arrivals, wet, wind lightand variable, downwind 3 on bothrunways, QNH 1015, temperature 11,low cloud 3/8 at 2,500, light rain in

area, many birds on the aerodrome,on your first contact with SydneyTower or Approach notify receipt."

The anemometer head which is locatedsome 30 feet above the ground at a positionon Sydney Airport indicated in Appendix Brecorded at 0912 hours on 18 July, 1971, amean surface wind velocity of 280 degrees6 knots. About this time the recorded winddirection varied between 260 degrees and 290degrees and the recorded wind speed variedbetween 5 and 8 knots. The upper windvelocities obtained from a balloon flight carriedout at 0900 hours were: 500 feet — 246 degrees,14 knots, 1,000 feet —245 degrees, 20 knotsand 2,000 feet —245 degrees, 24 knots.

A pluviograph and a rain gauge are bothlocated at Sydney Airport, as indicated inAppendix B. The pluviograph, which providesa progressive record of daily rainfall, recordeda total of 5 points of rain during the twentyfour hour period from 0840 hours on 17 July,1971 to 0845 hours on 18 July, 1971 andshowed that the entire 5 points fell between0630 and 0700 hours on 18 July, 1971. Therain gauge, which is read by the meteorologicalobserver at three hourly intervals, registereda total of 6 points for the period 0600 to 0900hours of 18 July, 1971. No further rain wasrecorded by either instrument during theremainder of 18 July, 1971.

1.8 AIDS TO NAVIGATION

Navigation aids were not a factor in theincident.

1.9 COMMUNICATIONS

Communications with the aircraft werenormal in all respects and were not a factorin this incident.

1.10 AERODROME AND GROUNDFACILITIES

Runway 25 at Sydney Airport is 8,298feet in length and 200 feet wide, but the landingthreshold is permanently displaced by 400 feetand, consequently, a distance of 7,898 feet isavailable for landing. The runway is aligned242 degrees magnetic (254 degrees true) andits elevation above mean sea level is 20

feet at the eastern end and 16 feet at thewestern end. The surface is composed ofbituminous concrete material with the excep-tion of 500 feet at the western extremity whichis composed of portland cement concrete. TheRunway 07 threshold stripes and identificationnumber have been painted on the cementconcrete area with white paint on a paintedblack background. At the time of this incidentit was evident that a number of layers of whitepaint had been applied to these markings andthe surface exhibited the usual powdery con-dition. The painted, fixed distance, touchdownzone markings and runway centre-line markingswere in a similar condition. The unpaintedrunway surface was in good condition exceptfor heavy rubber deposits in the vicinity of thetouchdown zones. At the western end, thesewere found in the area between 800 and 2,300feet from the western threshold and the heaviestdeposits were within the section of the runway1,300 to 2,000 feet from the threshold. In thisarea there was partial to complete filling ofthe pavement texture in the central portionof the runway.

Runways 16 and 07 at Sydney Airportwere equipped with full instrument landingsystems whilst Runway 34 had a T-VASISinstalled and Runway 25 had both RED/WHITE VASIS and T-VASIS installed toprovide visual approach slope guidance tolanding aircraft. In accordance with normalprocedures, the T-VASIS on Runway 25 wasilluminated for the landing approach ofCLIPPER 811 and the RED/WHITE VASISwas immediately available on request by thecrew of the aircraft.

1.11 FLIGHT RECORDERS

Flight Data Recorder The aircraft wasequipped with a Lockheed Aircraft ServiceModel 109D Flight Recorder which records, onan aluminium foil, vertical acceleration, head-ing, indicated airspeed and altitude against atime base.

At Appendix D there is a graph presen-tation of the flight data record commencingat an altitude of approximately 1,200 feetduring this landing approach. At Appendix Ethere is a profile of the final part of thisapproach and it is compared with the thresholdcrossing heights and touchdown points for 21

and 3 degree approach slopes. It should benoted that the touchdown points for the 2iand 3 degree approach slopes are for "no flare"landings and that the implementation of anormal landing flare would extend the touch-down points by about 500 feet.

From these Appendices it can be seen thatthe early part of the final approach from 1,200feet to 650 feet above the runway elevationwas well controlled in respect of airspeed,heading and slope angle. At about 650 feet,however, the aircraft diverged slightly abovethe desired approach slope and remained aboveit for the remainder of the approach. Below200 feet the achieved approach slope tendedto flatten somewhat to an angle of about 21degrees and the aircraft crossed the thresholdwith a wheel height indicated to be 123 feetinstead of with the desired wheel height of 62feet specified by Pan American Airways forthe 30 flap configuration and a 3 degreeapproach slope. The Operator has also specifieda minimum recommended approach slope of2.5 degrees which, in conjunction with thespecified aiming point of 2,000 feet beyond thethreshold and flap 30, will produce a minimummainwheel height at the threshold of 44 feet.

Below a height of about 50 feet abovethe runway the aircraft's static system is subjectto pressure changes arising from ground effectand, consequently, the shape of the altitudegraph and absolute height values depicted inAppendix D are unreliable in this area.Similarly, during deceleration the airspeedrecord is subject to a rapid dynamic changeand the graph suffers from the lag characteris-tic which the recorder is subject to under suchconditions.

Cockpit Audio Recorder A Fairchild Indust-rial Products Model A100 Cockpit AudioRecorder was installed in the aircraft. The tapefrom this recorder which provides a record ofthe cockpit audio programme including audiocommunications, over a 30 minute period wastaken into custody following the incident. Thetape was subsequently returned to PanAmerican World Airways whence a copy wasmade available to the National TransportationSafety Board in the U.S.A. who read it out.A transcript of the recording for a period ofabout 5i minutes embracing this incident wasmade available to the investigation and appearsat Appendix G.

1.12 WRECKAGE

Not applicable to this occurrence.

1.13 FIRE

There was no fire.

1.14 SURVIVAL ASPECTS

The accelerations to which the occupantswere subjected during the landing roll were ofa low order and the question of injury did notarise. Mobile stairways were used for thedisembarkation of the passengers and crew.

1.15 TESTS AND RESEARCH

Expected Landing Performance Althoughthere is no certification test data relating tothe landing performance of Boeing 747 aircrafton wet runways, some data on wet runwaylandings carried out by The Boeing Companyhas been included in their Performance Engi-neers Manual. From this data the performancechart at Appendix I covering landings on wetand dry runways using brakes, spoilers and 2reversers has been constructed.

Obviously, in the landing case, the airdistance from 50 feet and the transition distance(i.e. the runway distance consumed after touchdown up to the point where spoilers aredeployed and wheel braking applied) will notbe affected by the state of the runway surface.The braking distance is the only variable tobe accounted for in any comparison of theoverall landing distances on wet or dryrunways.

Appendix I indicates that, for a grossweight of 484,000 Ib, the landing ground rolldistance on a dry runway will be 2,460 feetincluding 2,030 feet of braking distance. Ona wet runway, the ground roll will be 3,770feet including 3,340 feet of braking distance.This implies a braking distance factor of 1.64for wet surfaces which, as a matter of possiblerelevance, is in quite close agreement with thecertified results of wet landing tests carried outon the Boeing 727/200 aircraft at the time ofits certification.

Evidence from Motion Picture Film Thetouchdown of CLIPPER 811 and the first 24seconds of the landing roll were recorded byan amateur photographer using a clockwork-

driven 8 mm movie camera from a knownposition on the observation deck of an airportbuilding. Landmarks within the camera's fieldof view confirm the touchdown position estab-lished from eye-witness and other evidence.From an examination of the film and, afterapplication of a correction to the film's runningspeed obtained by calibration of the camera,calculations indicated that the aircraft's groundspeed at touchdown was 129.6 knots to whicha tolerance of plus or minus 1 knot to accom-modate any possible variation in the clock-work spring tension of the camera may beapplied. The body angle at touchdown wasmeasured and found to be 4.7 degrees nose-up.One second after touchdown it was 4 degreesnose-up, 2 seconds after touchdown it hadreduced to 2.8 degrees and 3i seconds aftertouchdown it was down to 2.1 degrees nose-up.This body angle was substantially maintaineduntil 51 seconds after touchdown and thenit decayed at a uniform rate until the nose-wheel contacted the runway 9.5 seconds aftertouchdown. The film indicated that nosewheelcontact first occurred at a point 2,038 feetbeyond the mainwheel touch down point andthe ground speed of the aircraft at that timewas between 105 and 110 knots.

2 — Analysis

2.1 GENERAL

The circumstances of this incident presentthree principal questions for consideration.Why did the aircraft touch down so far alongthe runway?; why did the aircraft fail to cometo a halt in the runway length remaining aftertouchdown?; and why did the pilot not goaround at some time before the overrun becameinevitable? Before considering these threequestions in detail, however, it is necessary toexamine the circumstances in which thislanding approach was carried out.

There were no meteorological conditionswhich could have adversely affected the capacityof the pilot to carry out a normal landing.The approach was conducted in clear, daylightvisibility with no evidence of significantturbulence or wind shear and the pilot wasaware that the runway surface was wet.

There is no evidence of any conditionof health or of fatigue affecting the pilot'snormal judgment. The only item of aircraftunserviceability having any possible signifi-

8

cance to this occurrence was the INOPERA-TIVE status of the No. 1 engine thrust reverser.Because of the need to use symetrical reversethrust this condition limited the captain to theuse of reverse thrust on the inboard enginesonly during the landing roll. Undoubtedly theavailability of reverse thrust on all four engineswould have improved the aircraft's stoppingcapacity but the fact that only two enginescould be used in this role was well known tothe captain prior to his commencement of thelanding approach and the landing distanceavailable was more than adequate for a safelanding to be completed in this condition.

In accordance with the prescribed noiseabatement procedures the pilot was assignedthe landing runway which was most closelyaligned with the aircraft's arrival track and astraight-in approach was made from cruisingaltitude. The crew was given adequate noticeof the runway on which the aircraft could beexpected to land and, except for some requestsfor speed adjustments to facilitate trafficseparation, the air traffic control instructionsduring the landing approach were routine.The pilot-in-command has not suggested thatthe required speed adjustments in any wayaffected his landing approach.

The assigned Runway 25 was the most"into-wind" runway. It is accepted that, in theabsence of an instrument landing system glide-path, a straight-in landing approach calls forthe exercise of a high degree of pilot judgment.Nevertheless, a straight-in approach cannot beregarded as an abnormal procedure. Pilots aretrained in carrying out this type of landingapproach and the instrumentation in this typeof aircraft provides an adequate assistance totheir visual judgment. Alternatively, on thisoccasion two other runways which were suitablefor landing and equipped with electronic glide-path guidance were available and, on requestfrom the pilot, the aircraft would have beencleared to land on either of them.

In order to define the proper approachslopes to be used under visual conditions, theDepartment of Civil Aviation has installedvisual approach slope indicating systems(VASIS) on most of the runways not servedby instrument landing systems at the majorairports. The two best known VASIS are theRED-WHITE System and the Australian T-VASIS, both of which were installed on

Runway 25 at Sydney at the time of thisoccurrence. These systems were originallydesigned and aligned for use by smalleraircraft. With the advent of the wide-bodiedjets, of the Boeing 747 type, where the verticaldistance between the pilot's eye and the mainlanding gear is significantly greater and, in thenormal approach attitude, is of the order of40 feet, it became apparent that, in the originalconcept of their use, the existing VASISinstallations provided inadequate mainwheelclearance at the runway threshold. Examinationand testing of existing installations has shownthat, for the RED-WHITE system to be fullyusable by the wide-bodied jets, a modificationin the form of a further light bar up-wind ofthe standard system must be installed. Subjectto a procedural change, however, the T-VASISis quite satisfactory for use by the larger aircraftwithout modification of the standard instal-lation. In the case of the Boeing 747, it isnecessary for the pilot to maintain an approachslope indication of two-lights "fly down" insteadof the "on slope" indication applicable to thesmaller aircraft. This has the effect of increas-ing the height over the threshold without sig-nificantly affecting the approach slope angle.It presents no undue difficulties to the pilotand ensures adequate mainwheel clearance atthe threshold.

The T-VASIS installation on Runway 25at Sydney was commissioned during February,1964. The commissioning of the aid wasnotified to all operators, including PanAmerican World Airways, and its availabilitywas subsequently reflected in the Approachand Landing Charts issued in respect of SydneyAirport. Pan American World Airways, there-fore, had adequate advice of the installationand availability of the aid and information onits characteristics was readily available to them.Furthermore, on 17 September, 1970, shortlybefore Pan American World Airways com-menced Boeing 747 operations into Sydney, aletter containing information on the T-VASISand its applicability to Boeing 747 operationswas sent by the Department of Civil Aviationto the Pan American World Airways ExecutiveDirector for Australia. The Director has statedthat this letter was not received by him andit is apparent that the suitability of theT-VASIS for Boeing 747 operations was notbrought to the attention of Pan American flightcrews.

2.2 THE APPROACH TO TOUCHDOWN

The weight of evidence leaves no doubtthat the first touchdown occurred at a point4.003 feet beyond the runway threshold and,as is shown in Appendix B, this is some 2,500feet beyond the touchdown zone delineated bythe fixed distance markers. It is also grosslybeyond any description of the normal orexpected touchdown point contained in thePan American "Aircraft Operating Manual".

The reasons for this delayed touchdownmay be found in an examination of AppendicesE and F. The approach profile at Appendix Eshows that the aircraft crossed the thresholdwith a wheel height of 123 feet and with anapproach slope angle of 2| degrees. AppendixF, a graph supplied by The Boeing Company,indicates that this combination of excessivethreshold height and shallow approach slopewill result in overshooting the normal touch-down point by some 2,200 feet. Since thenormal touchdown point from a 3 degreeapproach slope in this type of aircraft, withdue allowance for 500 feet consumed duringthe landing flare, is specified by the manufac-turer as being 1,675 feet beyond the threshold,a touchdown in this case at about 4,000 feetbeyond the threshold is not a surprising result.

With due allowance for the prevailingwind velocity, an integration of the speed andaltitude data at Appendix D shows that theapproach, down to a height of about 700 feet,was consistent with a three degree approachslope appropriate to the normal, permanentlydisplaced, landing threshold on Runway 25.At a height of about 700 feet there was asubstantial flattening of the approach slopewhich coincided in time with the initiation ofa discussion in the cockpit, between the captainand first officer, as to the existence or other-wise of a displaced threshold. The evidence ofthis discussion is in the transcript of the cock-pit audio record at Appendix G. In the courseof the discussion, the captain provided apossible explanation for the change in approachslope in his statement "I'm going to give it alittle room . . ." Appendix D shows that theflattened approach slope was maintained fora period of approximately 30 seconds and thensteepened at a time which was approximatelycoincident with references, by the first officerto a "foreign kind of VASI", the indications

of which he interpreted as showing their aircraftto be too high on the approach.

The landing threshold for Runway 25 ispermanently displaced 400 feet in from theend of the runway and the displaced thresholdand runway markings were in accord withinternationally prescribed standards. Therewas no current NOTAM advice which indi-cated or suggested a further temporary dis-placement of the threshold from its normalpermanently displaced position. The fact thatthe threshold proper is displaced, however,could have been the factor which promptedthis cockpit discussion, either as a result of avisual observation at the time or as a resultof some memory cue. On the other hand thecockpit discussion could have been promptedby some other visible feature and, notwith-standing some intelligibility problems in thetranscription of the audio record, the possibilitythat the "on-slope" bar of the T-VASISsystem, in association with the nearby 1,000foot fixed distance markers (see Appendix H)was mistaken for an indication of a displacedthreshold is tenable in the light of the termsof the recorded conversation. The availableevidence docs not permit further resolution ofthe reason for the displaced threshold discussionand it was not practicable for the investigationto fur ther pursue this aspect. Nevertheless, itcan be concluded that some doubts did ariseon the flight deck as to the position of thelanding threshold, that there was an adoptionof a flight path more cautious in respect of anypossible undershoot and that the adjustmentof the flight path, apparently to achieve thispurpose, was substantial.

The available landing distance, as deter-mined in relation to the permanently markedthreshold, provided a margin of 998 feet inexcess of the computed landing distancerequired in the prevailing circumstances. Anyassumption of a further displacement of thethreshold or any action to give the thresholdproper "a little room" by deliberately settingout to land further into the runway than isnormal would have reduced this margin. Forexample, the margin existing in relation to alanding predicated on an assumed thresholdat the T-VASIS would have been only 98 feet.It can be argued that the touchdown zonemarking provided a relatively precise basis forthe assessment of any diminution of the avail-able landing distance arising from an assump-

10

tion of a displaced threshold but, having regardto the consequential reduction of availablemargins, continuation of the operation on thispremise would demand an increased vigilancedirected to achieving touchdown at theoptimum position. Alternatively, it shouldhave been apparent that any doubts as to thetrue position of the landing threshold couldhave been resolved by an interrogation ofSydney Tower and this would have been aprudent action even at the expense of aban-doning the current approach. The captain didnot make any attempt to follow such a courseof action.

Whilst the available evidence is not suchas to allow a firm determination of the factorgenerating the flight crews' discussion as to adisplaced threshold, it is reasonable to assumethat any doubts which they had, did notinvolve an assumption of displacement beyondthe first 1,000 foot fixed distance marker. Inthis, the worst case, the expected touchdownpoint for a normal landing, including dueallowance for the flare, would be at approxi-mately 2,700 feet beyond the landing thresholdproper. Thus, the relationship of the actualtouchdown point at 4,003 feet to the touchdownpoints which would result from properly judgedapproaches, based on thresholds at or withinthe first 1,000 feet of runway, represents aminimum judgment error of 1,300 feet and apossible error of up to 2,300 feet. The markingon Runway 25 provided ample reference datafor a properly judged approach to the singlelanding threshold displayed. Furthermore,within the pilot's visual reference area, thephysical features of the airport were such thathe should have been able to accurately assessthe misjudgment which followed the approachslope adjustment before he finally committedthe aircraft to a ful l stop landing.

2.3 THE FAILURE TO STOPON THE RUNWAY

The performance data at Section 1.15 ofthis report and at Appendix I indicates that,on a wet runway, using brake's, spoilers andthe thrust reversers from two engines it ispossible to stop a 484,000 Ib gross-weightaircraft in a ground roll distance of 3,770 feet.From the position at which the aircraft firsttouched down on the runway," 4,003 feetbeyond the threshold, the runway distance

remaining in which to bring the aircraft to ahalt was 3,895 feet. In addition there is 200 feetof low strength pavement beyond the etid of therunway which is not considered suitable fornormal operations, but which can be used forstopping in an emergency situation even thoughthe surface might be damaged or evenpenetrated.

Despite the apparent existence of anexcess of 325 feet of sealed surface in theavailable stopping distance, there are, first ofall, some reasons why the capacity of the air-craft to stop in the available distance shouldbe regarded as marginal. Although the databasic to the wet runway performance chartwas obtained from actual tests conducted onwet runways, it is not possible to reliablycompare the degree of wetness of the testrunways with that pertaining at Sydney atthe time of this incident. Similarly, it is notpossible to accurately compare the surfacetexture of the test runways with that of theSydney runway. It is, however, reasonable toassume that the tests were landings in whichthe touchdown occurred at the normal positionon the runway and that the braking zonecomprised relatively clean pavement unaffectedby touchdown rubber deposits and paintedareas. In this particular landing, however, thepavement in the braking zone comprised a largearea of rubber-filled surface and some paintedareas where the braking co-efficient wasalmost certainly lower than that achieved underthe test conditions.

In addition to these considerations as tothe capacity of the aircraft to stop, there isalso some evidence that the aircraft's fullbraking potential was not utilised in thislanding. The nosewheel remained off theground for a period of 9.5 seconds aftermainwheel touchdown and, in this time, theaircraft traversed a distance of approximately1,945 feet. In all of the landings carried outduring certification of the aircraft type thenosewheel was on the runway within twoseconds of mainwheel touchdown and asampling of 36 landings in an airline trainingoperation produced an average interval betweenmainwheel and nosewheel touchdown of fiveseconds.

The chart at Appendix C indicates thatthe discernible braking marks commenced at apoint on the runway 1,714 feet from its end

11

and thus some 236 feet beyond the mainwheelposition at the time of nosewheel touchdown(the distance between the nosewheel and rearmainwheel axes in this aircraft is 92 feet). Thefilm has shown that the aircraft's groundspeed at the time of nosewheel touchdownwas 105 to 110 knots which suggests a ratherlow degree of retardation between mainwheeltouchdown and this point. Discussions with TheBoeing Company indicate that the very power-ful elevator control on this aircraft permits alarge proportion of the available brakingcapacity to be employed before the nosewheelis on the ground but it would seem that allof this capacity was not used by the pilot-in-command during the nosewheel hold-off periodof 9.5 seconds.

From the point where the first wheelbraking marks were evident on the runway,it is apparent that heavy braking was main-tained continuously throughout the remainderof the ground roll on the runway and over-run.The cockpit audio record also suggests that thespoilers were deployed some 4-6 seconds aftermainwheel touchdown (i.e. before there wasnosewheel contact) and this is consistent withthe adoption of a maximum deceleration mode.It is not possible to determine the speed atwhich the aircraft left the end of the runwayand, later, the low strength pavement, but thelack of damage to the aircraft and the relativelyshort distance that the aircraft travelled throughthe sand attest that a very substantial decreasein speed occurred beyond the point where itis first evident that mainwheel braking wasbeing employed.

Although no firm conclusion can be drawnit seems likely that, had the pilot placed thenosewheel on the ground earlier and there-after applied maximum braking, the aircraftwould not have over-run the runway or at leastit may have been brought to a stop on the lowstrength pavement. The available margin wasso small, however, and the variables affectingthe result so significant, that the ability of theaircraft to stop in the runway length remainingcannot be determined with certainty.

2.4 THE GO-AROUND CONSIDERATION

A straight-in approach without electronicor visual glideslope guidance is more demand-ing of accurate visual judgment from the pilotthan one carried out with such an aid or

following a normal visual circuit and, in thesecircumstances, the possibility is heightened thatthe approach may have to be abandoned anda go-around carried out. There are a numberof factors which will determine the last pointfrom which a go-around can be safely accomp-lished, but The Boeing Company recommendsthat a go-around shall not be attempted fromthe landing roll once the reverse thrust levershave been actuated.

When asked if he considered a go-aroundat any stage during this approach and landingthe captain said that he did not think suchan action was necessary. It is apparent, never-theless, that the aircraft was inordinately highcrossing the threshold proper and still had amain wheels height of 78 feet above the runwayat the position of the 1,000 foot distancemarker. In fact, before a normal thresholdheight of say 50 feet above the runway wasachieved some 2,000 feet of its length hadalready been consumed. In these circumstancesit is just as difficult to understand the captain'sbelief that a touchdown was achieved shortlyafter passing Taxiway 'N' as it is to understandwhy he failed to appreciate the excessive heightof the aircraft at whichever threshold he wasusing.

There can be no doubt that this was anapproach which should have been abandonedperhaps as early as the point at which doubtarose on the flight deck as to the real positionof the landing threshold. Certainly in theensuing 78 seconds to touchdown there wasno impediment to the initiation of a go-aroundand the rapidly dwindling safety marginsimplicit in the excessive height of the aircraftmade this action imperative. Perhaps theemployment of a maximum deceleration effortafter touchdown might still have brought theaircraft to a halt on the runway but such apersistence with an operation from which allsafety buffers had disappeared cannot becondoned, particularly, when a safe alternativecourse of action was available.

3 — Conclusion1. The flight crew members of the aircraftwere properly licensed and experienced to carryout their duties.

2. There was no evidence of any defect inthe aircraft which could have contributedsignificantly to the incident.

12

3. In the relevant circumstances of thislanding and, after the addition of theappropriate factor for a wet runway surface,the landing distance required was some 1,000feet less than the landing distance availableon Runway 25.

4. At the time of this incident a visualapproach slope indicating system (T-VASIS)suitable for use by aircraft of this type, wasoperating on Runway 25. The Department ofCivil Aviation, on 17 September 1970, forwar-ded to the Executive Director for Pan AmericanWorld Airways in Australia advice as to theavailability and characteristics of this system.The Director has said that he did not receivethis advice. Consequently, it did not becomeavailable to the flight crew and this visualaid was not used, as such, by them during thelanding approach.

5. When the aircraft was approximately twomiles from the end of the runway, at a heightof about 700 feet, the captain flattened theapproach slope apparently in the belief thatthis action was necessary to allow for theexistence of a displaced threshold. The captainmisjudged the approach slope alteration andthe aircraft crossed the landing threshold andthe whole of the marked touchdown zone atan excessive height and with a shallower-than-normal approach slope, to finally touch down

4,003 feet beyond the landing threshold or3,895 feet from the upwind end of the1 runway.

6. It is probable that the spoilers weredeployed within 4-6 seconds of a mainwheeltouchdown but the nosewheel touchdown didnot occur until 9.5 seconds after the firstmainwheel touchdown.

7. There was no evidence of braking markson the runway until the aircraft had travelleda distance of 2,181 feet beyond the mainwheeltouchdown or 236 feet beyond the nosewheeltouchdown point. Thereafter, there wasevidence of heavy brake application during theremainder of the aircraft's ground roll.

8. The aircraft over-ran the runway and,after turning 37 degrees to the right, becamebogged in soft ground with its nosewheel 325feet beyond the end of the runway.

9. It has not been possible to determine withcertainty whether or not, even with optimumretardation actions, the aircraft could havebeen stopped in the runway distance remainingafter mainwheel touchdown.

Cause10. The cause of the incident was that thepilot-in-command did not take a timely decisionto initiate go-around procedures in the circum-stances of a misjudged landing approach.

13

Appendix A

The nose undercarriage of N652PA showing the depth to which the wheels penetrated the softearth.

14

Q.5'

The aircraft as it came to rest a short distance beyond the end of the runway.Note the sunken perimeter road and the sewage outfall.

Appendix B

PLUVIOGRAPHr&SU? RAIN GAUGE

CONTROL TOWER& FIRE SERVICE

!*3MAIN WHEEL TOUCH-DOWNiJ&c oni MT

INTERNATIONAL APRONCONTROL TOWER

NOSE WHEEL TOUCH-DOWN 1945 APPROX. FROM MAINWHEEL .

PLAN VIEW OF SYDNEYJ AIRPORT RUNWAY 25

1950 APPROX. FROM NOSEWHEEL'.

16

<J.3

FIXED DISTANCE MARKINGS

BRAKING MARKS ON RUNWAY

100 0I I

Scde of feet

100 20O JOO 40OI

Appendix D

INDICATEDAIRSPEED

KNOTS140

130

120

110

100

90

80

70

60

50

40

30

20

10

MAGNETICHEADINGDEGREES

2SO

270

260

INDICATED AIRSPEED

VERTICALACCELERATION

'G1

VERTICAL ACCELERATION

WHEEL HEIGHTABOVE RUNWAY

FEET

1400

1300

12 OO

1100

1000

9OO

800

7OO

600

500

400

3OO

200

100

20 4OTIME IN SECONDS

80 100 120

19 Recorded flight data during approach and landing.

FINAL APPROACH PROFILE ANDTOUCH-DOWN POINT.

DESIRED AND MINIMUM GLIDESLOPES SHOWN FORCOMPARISON OF THRESHOLD CROSSING HEIGHTSAND TOUCH-DOWN POSITIONS.

3895 FEET TO ENDOF RUNWAY

4003

FROM THRESHOLD

PRESCRIBED AIMING POINT FOR ALLAPPROACHES 2,000 FEET

1175' 1010'

FROM THRESHOLD

RUNWAY THRESHOLD(DISPLACED 400 FEET)

g

•o•a3°r5'W

Appendix F

I-LLJUJU.

8

UJO

1005O

<o

UJ

Xo

GLIDE PATH ANGLE - DEGREES

FLAT GLIDE SLOPE PATH AND EXCESSIVE HEIGHTOVER END OF RUNWAY COMBINE TO EXTENDLANDING DISTANCE REQUIRED DUE TO RUNWAYUSED BEFORE TOUCH DOWN.

BROKEN LINE INDICATES SITUATION OF N652PADURING THE LATER STAGES OF THIS APPROACH.

APPROACH HEIGHT EFFECT

21

Appendix G

NATIONAL TRANSPORTATION SAFETY BOARD

Bureau of Aviation SafetyWashington D.C.October 26, 1971

SPECIALIST'S FACTUAL REPORT OF INVESTIGATIONCOCKPIT VOICE RECORDER

A. INCIDENTLocation: Sydney, AustraliaDate: July 18, 1971Aircraft: Boeing 747, Pan American World Airways Flight 811

B. GROUPNot applicable.

C. SUMMARYNot applicable.

D. DETAILS OF INVESTIGATION

The transcription, which appears as an attachment hereto, was prepared at the requestof the Department of Civil Aviation, Commonwealth of Australia. The data source was a copyof the original cockpit voice recorder (CVR) tape provided to the undersigned by the operatorat the request of the Investigator-in-Charge. The copy was of the cockpit area microphonechannel only.

The CVR was a Fairchild Model A-100, serial number unknown. Its condition wasunknown. The tape copy provided was satisfactory in respect to intelligibility of communicationsrecorded thereon. Investigation disclosed that the original tape had been operating from 5 to7% faster than nominal speed. According to the manufacturer, this could have occurred ifthe CVR was recording at the upper limits of its speed tolerance (2-3%) and the frequencyof the aircraft generated electrical current was 3-4% above its nominal 400 Hz level.

Subsequent to the landing roll-out and the incident concurrent therewith, therecorder was allowed to operate for some ten minutes or so prior to being shut down. Thus,the attached description does not reflect the last 5i minutes of recording but rather a 5iminute segment of flight along the final approach course, the landing and roll-out, thedeparture from the paved runway surface and about 3/4 minute thereafter.

Robert D. RudichAttachment Chief, Audio Laboratory

22

Appendix G (Continued)

TRANSCRIPTION OF 54- MINUTES OF COCKPIT VOICE RECORDING

PAN AMERICAN WORLD AIRWAYS BOEING 747, FLIGHT 811

SYDNEY, AUSTRALIA, JULY 18, 1971

CAMRDO-1-2-3

SOURCE& TIME

0:00CAM-1

0:02CAM-20:06.6CAM-3CAM-2CAM-1CAM-3CAM-2CAM-3CAM-2CAM-3

0:25.6CAM-2CAM-3CAM-2

0:30.3CAM-1CAM-2CAM-2CAM-?CAM-2

0:47.5CAM-1CAM-2CAM-2

LEGEND

Cockpit area microphone voice or sound sourceRadio transmission from Flight 811Voice identified as CaptainVoice identified as First OfficerVoice identified as Second OfficeT (Flight Engineer)Voice unidentifiedUnintelligible wordQuestionable textEditorial insertionNote: Times shown are cumulative, from beginning of transcription.

CONTENT

Might as well try to make these altitudes

Sure, okay, you have, ah, two thousand feet and another mile and a half to go

Gear is down, no smoking's on, VOR-ADF selectors?VOR -- VOR approachCorrect positionYou want to check me on that gear down?Gear is down, one green lightSpeed brake(Forward)Wing flaps

They are at ten degrees right nowStanding byOkay

Seven milesSeven miles, two thousand feet'kay, you're seven hundred and fifty feet to minimums(Guess) we're not hereThat's just for three miles

Okay, flaps twentyFlaps going two zeroHell of a place for a graveyard - - prime real estate

23

Appendix G (Continued)

1:07.0CAM-1CAM-2CAM

1.17.0CAM-1CAM-2CAM-3

1:23.7CAM-2CAM-2CAM-?

1:27.5CAM-2CAM-3CAM-2CAM-?CAM-3

CAM-2CAM-2CAM-?CAM-?

2:19.4CAM-1CAM-2CAM-?CAM-2CAM-1CAM-1CAM-2CAM-1CAM-2

2:43.7CAM-?CAM-2

2:56.2CAM-2

3:02.2CAM-2

3:08.4CAM-2

Flap twenty-fiveFlap twenty-fiveSound similar to flap handle entering detent

And flap thirtyCoin' to thirtyOkay, wing flaps

They're set for twenty-five, they won't go down yetGate switchThere - -

There they go —Okay

set for thirty'kay, I got a green lightHydraulic pressure and quantity are normal, engine ignition at flight start, landingchecklist is completeAbsolutely beautifulThis thing * * going right to the right, 'n off we go(Sorry about that)* * (O'Hare)

There's a displaced threshold, (Ron)Not on this one - - oh, we do * *((multiple voices)) * yeah, marked, yeah * *No * * * not USed to that, that may mean a VASI, you knowWell, it could at that, but — yeah, it couldWell, I'm going to give it —* * * has VASII'm going to give it a little room andNo, that's just got the thousand foot marker on the runway, I don't see anydisplacement there, if it is displaced.

The birdsYeah - - that should show the VASI so that's the VASI. Could be it's that foreignkind of VASI - - shows too high, I guess

'kay, one forty-four, seven hundred feet a minute, three hundred feet above theground.

One forty-three, seven hundred feet a minute, two hundred feet above the ground.

One forty-two, two hundred feet

24

Appendix G (Continued)

3:13.2CAM-2

3.13.2CAM-2

3:20.7CAM-2

3:26.6CAM-2

3:31.4

3:35.5

3:38.7CAM

3:45.1CAM

3:49.2CAMCAM-2

3:51.2CAM-3

3:53.0CAM-2

4:03.5CAM-24:05.3CAM

4:06.9CAMCAM-3CAM-1CAM-?CAM-1CAM-2CAM-1CAM-1CAM-1CAM-1CAM-2

4:49.9RDO-1

One forty-four, six hundred feet a minute down, one hundred

and fifty feet

One four three, one hundred feet, six hundred feet a minute down

One forty-eight, fifty feet

One forty-five, fifty feet

One forty ((spool-down commences))

Light sound of lever click

Heavier sound of lever click

Multiple sounds of lever clicks* *

Inboards full reverse ((sound of engine spool up))

You're at a hundred knots, get on 'em!!

Sixty knots!

Sound of first bang

Sound of second bang followed by engine spool-downSaved that one!(Shut 'em)Okay((on public address system)) Do not evacuate, do not evacuate the airportYou want to cut 'em?YeahYou'll have to make some radio contactsAh, keep this one on((on public address system)) Tower from Clipper eight elevenYou're on PA, you're on PA

Tower from Clipper eight eleven, will you send the fire trucks out? We have,ah, run off the end of the runway, (done) practically no damage. However, sendthe, ah, trucks and evacuation ladder, please.End of pertinent recording.

25

Appendix H

Runway 25 as seen from a position on a three degree approach slope, approximately two milesfrom the landing threshold.

26

Appendix I

FLAPS 30

until

LU

I

UJ

2 3<</>Q

I I I I T i I I I I I I I i I I i i in i i i i:UNFACTORED LANDING DISTANCES

FROM 50 FEET MS- ( INTERLOCK) -SELECTED-

BRAKES, SPOILERS AND REVERSERS (2)_i-_-i i i_L_.

ANTI-SKID OPERATIVESEA LEVEL STANDARD DAYZERO WIND & SLOPE -M-MANUAL SPOILERS

450 500GROSS WEIGHT - 1000 LB

60U

Boeing 747 landing performance chart.

27

71-2