In-flight upset - 154 km west of Learmonth, WA, 7 October 2008,

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• The flight crew provided inputs to the EFCS, either indirectly using the autopilotor directly using the flight crew controls. The controls included the sidestickcontrollers (or sidesticks) to manoeuvre the aircraft in pitch and roll, and footoperatedrudder pedals to control yaw.• The air data and inertial reference system (ADIRS) provided information onimportant flight parameters such as airspeed, altitude, angle of attack (AOA),and attitude to the EFCS and autopilot, as well as to the flight displays used bythe crew.Figure 3: Simplified overview of the relationship between aircraft systems1.6.3 Electrical flight control system (EFCS)System overviewThe A330’s electrical flight control system (EFCS) was a ‘fly-by-wire’ system.That is, there was no direct mechanical linkage between most of the flight crew’scontrols and the flight control surfaces. 25 Flight control computers sent movementcommands via electrical signals to hydraulic actuators that were connected to thecontrol surfaces. 26 The computers sensed the response of the control surfaces tothese commands, and adjusted the commands as required.Figure 4 provides an overview of the Airbus fly-by-wire system, and Figure 5shows the flight control surfaces on the A330.25A330s are described as either ‘basic’ or ‘enhanced’ models (QPA was an enhanced model). Basicmodels have a mechanically-controlled rudder while the later enhanced models have fly-by-wirerudder control. For both models, elevator trim included a mechanical backup.26On a conventional airplane‚ inputs from the pilots or the autopilot were transmitted to thehydraulic actuators by an arrangement of mechanical components.- 10 -
Figure 4: Overview of a fly-by-wire flight control systemFigure 5: A330 flight control surfacesThe A330 EFCS had three flight control primary computers (FCPCs, commonlyknown as PRIMs) and two flight control secondary computers (FCSCs, commonlyknown as SECs). One of the FCPCs (normally FCPC 1) acted as the ‘master’FCPC. It computed the appropriate control orders, and sent these orders to the othercomputers to action. More detailed information regarding the functioning of theFCPCs is provided in section 2.1.Overall, the A330’s EFCS provided many advantages relative to a conventionalflight control system, including stability augmentation, reduced crew workload, andflight-envelope protection.Flight control lawsThe master FCPC computed the control orders according to a ‘control law’, withdifferent functionality provided depending on the law being used. There were threelevels of control law, and each level provided different functionality as follows:• Normal law. The EFCS detected when the aircraft was approaching the limits ofcertain flight parameters, and commanded control surface movements to preventthe aircraft from exceeding these limits (that is, it prevented the aircraft from- 11 -
Page 1: ATSB TRANSPORT SAFETY REPORTAviatio
Page 4 and 5: Published by: Australian Transport
Page 6 and 7: 3 FACTUAL INFORMATION: AIR DATA INE
Page 9 and 10: DOCUMENT RETRIEVAL INFORMATIONRepor
Page 11: TERMINOLOGY USED IN THIS REPORTOccu
Page 14 and 15: CSMCSSCVRDADSDCDGACDMCDMUEASAECAMED
Page 16 and 17: RAMRTCASATCOMSAESAOSDSECSEESEUSSASS
Page 18 and 19: FCPC design limitationAOA is a crit
Page 20 and 21: - xviii -
Page 22 and 23: associated with a master caution ch
Page 24 and 25: Figure 2: Aircraft track and key ev
Page 26 and 27: The crew decided that they needed t
Page 28 and 29: 1.3 Damage to aircraftThere was sig
Page 32 and 33: exceeding a predefined safe flight
Page 34 and 35: Table 1: Examples of ADIRU flight d
Page 36 and 37: Inertial reference partThe IR part
Page 38 and 39: ADIRS switching controlsIn normal o
Page 40 and 41: Processing by ADIRUs and FCPCsEach
Page 42 and 43: The information presented on the fl
Page 44 and 45: A system could flag its output data
Page 46 and 47: Table 4: Summary of indications for
Page 48 and 49: Figure 17: ECAM engine / warning di
Page 50 and 51: Table 6: Required actions associate
Page 52 and 53: For internal aircraft communication
Page 54 and 55: Table 7: Sequence of events (from t
Page 56 and 57: In summary, the source of most of t
Page 58 and 59: Summary of IR data for the occurren
Page 60 and 61: Figure 22: QAR plot showing oscilla
Page 62 and 63: QAR dataOverall, the QAR recorded 4
Page 64 and 65: Flight crew pitch inputsDuring manu
Page 66 and 67: They provided information for maint
Page 68 and 69: Table 11: Cockpit effect messages d
Page 70 and 71: Table 13: Troubleshooting data rela
Page 72 and 73: position 1 on QPA. Further details
Page 74 and 75: class 1 fault messages shown in Tab
Page 76 and 77: If there was a discrepancy between
Page 78 and 79: 1.15 Survival aspectsInformation on
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did not identify any faults. The BI
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Comparison of the three occurrences
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1.17.2 Processes for reporting and
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2 FACTUAL INFORMATION: ELECTRICAL F
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monitored external systems that pro
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Each FCPC used a number of paramete
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AOA computation logicThe FCPC softw
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Figure 29: FCPC processing of sever
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Table 19: Characteristics of elevat
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Simulation of AOA values for the fi
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2.2.2 Review of recorded flight con
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second PRIM 3 FAULT. The role of ma
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The ACJ was built around the princi
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• It stated that the identificati
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The second part of the V-cycle invo
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• Functional requirements. These
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2.4.5 Safety assessment activitiesG
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equipment software and aircraft ins
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2.5.4 Factors associated with the i
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it is very difficult if not impossi
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applicable to highly-integrated or
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Ongoing developmentsA range of rese
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To conduct an effective fault tree
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According to this model, accidents
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3 FACTUAL INFORMATION: AIR DATA INE
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• inertial reference input/output
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3.3 Examination of data-spike patte
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Figure 38: ARINC 429 word for an AO
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3.3.4 Data-spike patterns for the 7
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Figure 43: Qualitative correlation
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etween the values of any of the fou
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3.4.3 Calculating parameter valuesA
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3.4.5 Packaging the ARINC 429 wordT
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3.4.8 Transmitting data to other sy
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ARINC 429 packaging analysisThe ADI
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component configurations of differe
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manufacturer reported such BITE dat
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3.6 Potential trigger types3.6.1 Ba
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such as liquids or small loose frag
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wires). The electric 144 field stre
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Although the investigation could no
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3.6.6 Single event effectsBackgroun
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until a few years ago, were not dir
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Unit testingIn 2005, as part of the
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that involved a NAV IR and/or NAV A
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EMI from other aircraft systems (su
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from ADIRU 1 was not correctly reco
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• Detected failure. Any failure w
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The ADIRU manufacturer’s analysis
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the aircraft and ADIRU manufacturer
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4 FACTUAL INFORMATION: CABIN SAFETY
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Summary details of the cabin crew
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section, and the ninth flight atten
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Table 29: Significant cabin communi
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Figure 48: Example of damage to the
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4.3.2 Seat belt examinationsSix pas
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The flight crew’s procedures requ
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takeoff, landing or when the seat-b
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Table 31: Levels of injuryInjury le
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4.6.4 Injuries to seated occupants
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The percentage of occupants who wer
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Statistical analyses 197 were done
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passengers reported that they had h
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that seat belts should be worn only
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4.8.2 Handholds in the cabinThe FAA
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Figure 53: Overview of the 7 Octobe
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process needs to ensure that there
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and determine whether they could le
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useful in this case. If the EFCS sp
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5.3.2 Risk associated with the fail
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• All three events occurred in a
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place. Although aviation manufactur
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equiring cabin crew to enforce the
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With the information available to t
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ADIRU 1 affected the operation of a
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6 FINDINGSFrom the evidence availab
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• As of April 2010, the LTN-101 a
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did not illuminate. The new OEB (A3
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modifications were made to its guid
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this advice. At the time of the fir
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APPENDIX A: VERTICAL ACCELERATIONST
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APPENDIX B: FLIGHT RECORDER INFORMA
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APPENDIX C: POST-FLIGHT REPORTThe f
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- 231 -
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- 233 -
Page 255 and 256:
APPENDIX D: OTHER DATA-SPIKE OCCURR
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Occurrence on 27 December 2008Overv
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Figure D2: FDR data for the 27 Dece
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ADIRU informationADIRU 1 was the sa
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APPENDIX E: ADIRU TESTINGTest plan
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Visual inspectionsExternal visual i
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(ADR) output databuses. Loading on
Page 269 and 270:
Unit 4167 passed 2,223 of 2,272 tes
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dwells (sustained testing at a fixe
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APPENDIX F: AIRCRAFT LEVEL TESTINGI
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APPENDIX G: ELECTROMAGNETIC RADIATI
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cannot be ‘decoded’ by the rece
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APPENDIX H: SINGLE EVENT EFFECTSNot
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Factors affecting SEE exposureAn ai
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portions of memory are constantly b
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Depending on the form of EDAC, sing
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• crew actions: the passenger’s
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The questionnaire respondents were
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was centred across the passenger’
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Previous occurrencesThe seat belt m
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Australian turbulence eventsThe mos
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APPENDIX L: SEAT BELT USE IN ROAD V
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Table L1: Recent seat belt use rate
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US Federal Aviation AdministrationT
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APPENDIX N: SOURCES AND SUBMISSIONS
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Hanson, RJ 1987, Conducted electrom
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Tvaryanas, AP 2003, ‘Epidemiology
Page 313:
In-flight upset - 154 km west of Le
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In-flight upset - 154 km west of Learmonth, WA, 7 October 2008,

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