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

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messages. After other tests had been conducted, further BITE data was successfullywritten by the ADIRU and then downloaded with no anomalies or recorded faults.ADIRU 4687 recorded three fault messages and ADIRU 4663 contained five faultmessages, and all of these messages related to the performance of ADIRU4167 (section 1.12.6). ADIRU 4122 (from the 27 December 2008 occurrence)exhibited the same type of anomalies in the BITE data as ADIRU 4167 from the7 October 2008 occurrence (Appendix D).Maintenance test procedureThe maintenance test procedure was a standard procedure that was performed on allproduction and service ADIRUs. It tested hardware functionality, includingnavigation performance and the download of BITE data. It consisted of a total of177 specific subtests. Results from these tests were compared with the acceptancetest procedure results from the most recent service on the units.As the procedure loaded special test software to replace the normal flight software,it was performed after the operational flight program integrity check. The flightsoftware was then re-installed at the end of the procedure.A system functional test was also conducted as part of the standard maintenance testprocedure with a navigation performance (‘drift’) test. The navigation performancetest was run on a moving platform to exercise the unit’s inertial sensors, firstly for1 hour from a cold turn-on and another hour from a warm turn-on. An additionalBITE data download was performed after the navigation performance test.No problems were identified with any of the units.Acceptance test procedureThe acceptance test procedure was normally conducted on production and serviceADIRUs after a unit had been disassembled to ensure its proper reassembly. Ittested hardware functionality including navigation performance and download ofBITE data. It was similar to the maintenance test procedure, although lesscomprehensive as it did not overwrite the unit’s operational flight program(software). Since the acceptance test procedure could be conducted withoutchanging a unit’s configuration, the unit could subsequently be tested while still inits ‘original’ condition. No problems were identified.Databus output waveform measurement and data monitoringThis test focused on the ARINC output transmission circuitry. The goal was toestablish if data anomalies could be observed that were similar to spike anomaliesrecorded during the occurrence. The procedure was performed on the engineeringmanual integration test station (MITS). This was the same station used for allsoftware integration and formal software testing. The station capabilities allowedreal-time monitoring of any BITE failures that may occur. It also separated out allARINC databuses so that they could be loaded or connected to any receivingequipment desired.The ARINC transmission levels were measured using an oscilloscope, inspected forindications of noise or abnormal waveforms, and compared to the ARINCspecification. This was repeated on all inertial reference (IR) and air data reference- 246 -
(ADR) output databuses. Loading on each output bus (that is, the number of deviceson the bus) was varied from none to the maximum specified by ARINC 429(20 devices).For unit 4167, two ADR output databuses (ADR 7 and ADR 8) exceeded theno-load negative voltage limit by a very small amount. The failures were consideredto be a result of measurement equipment tolerance and not related to theoccurrence. 210 Some output data values exceeded the test’s data variationtolerances, which were used to detect excessive variations in the ADIRU’s outputdata. These were attributed to variations arising from the ADIRU being switchedON and OFF during the test, and to scaling errors in the test software. Accordingly,the variations were considered a result of minor problems with the test proceduredesign.These issues were not considered relevant to the occurrences under investigation.No other problems were identified.Module-level testingThe units underwent a detailed bench test that involved dismantling the unit andconducting functional tests of each module to identify any malfunctioning circuitrythat was not evident at the system level. These activities included:• the removal and inspection of modules for damage, heat damage, foreignmaterial or residue, connector contamination, loose components, and solder jointintegrity;• motherboard and motherboard connector inspection;• a rear panel EMI protection diode conduction check; and• individual module functional tests.For unit 4167, the following aspects were noted:• Some minor failures occurred as a result of problems with the design of the testprocedure.• An analogue-to-digital converter within the (inertial) sensor electronics modulewas found to be out of tolerance. The ADIRU would normally detect and correctfor the error when the module was installed.• A failure occurred within the power supply of the inertial sensor electronics, butdid not reoccur when the test was repeated several times.For unit 4122, the following aspects were noted:• Some minor failures occurred as a result of problems with the design of the testprocedure.• Some minor physical anomalies not related to the data-spike failure mode (forexample, insulation damage on a wire used only by test equipment) wereobserved. A waxy residue was found on the connector sockets on the sensorelectronics module. The residue had been deposited during manufacture as the210ADR 7 was always connected to a load in the A330-300 installation, so it would be very unlikelyto exceed tolerances when in actual operation. ADR 8 was not connected to any other systems inthe A330-300 installation and any fault with that databus would have no effect on the aircraft.- 247 -
Page 1:
ATSB TRANSPORT SAFETY REPORTAviatio
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Published by: Australian Transport
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3 FACTUAL INFORMATION: AIR DATA INE
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DOCUMENT RETRIEVAL INFORMATIONRepor
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TERMINOLOGY USED IN THIS REPORTOccu
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CSMCSSCVRDADSDCDGACDMCDMUEASAECAMED
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RAMRTCASATCOMSAESAOSDSECSEESEUSSASS
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FCPC design limitationAOA is a crit
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- xviii -
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associated with a master caution ch
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Figure 2: Aircraft track and key ev
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The crew decided that they needed t
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1.3 Damage to aircraftThere was sig
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• The flight crew provided inputs
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exceeding a predefined safe flight
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Table 1: Examples of ADIRU flight d
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Inertial reference partThe IR part
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ADIRS switching controlsIn normal o
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Processing by ADIRUs and FCPCsEach
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The information presented on the fl
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A system could flag its output data
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Table 4: Summary of indications for
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Figure 17: ECAM engine / warning di
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Table 6: Required actions associate
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For internal aircraft communication
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Table 7: Sequence of events (from t
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In summary, the source of most of t
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Summary of IR data for the occurren
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Figure 22: QAR plot showing oscilla
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QAR dataOverall, the QAR recorded 4
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Flight crew pitch inputsDuring manu
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They provided information for maint
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Table 11: Cockpit effect messages d
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Table 13: Troubleshooting data rela
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position 1 on QPA. Further details
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class 1 fault messages shown in Tab
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If there was a discrepancy between
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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
Page 216 and 217: and determine whether they could le
Page 218 and 219: useful in this case. If the EFCS sp
Page 220 and 221: 5.3.2 Risk associated with the fail
Page 222 and 223: • All three events occurred in a
Page 224 and 225: place. Although aviation manufactur
Page 226 and 227: equiring cabin crew to enforce the
Page 228 and 229: With the information available to t
Page 230 and 231: ADIRU 1 affected the operation of a
Page 233 and 234: 6 FINDINGSFrom the evidence availab
Page 235: • As of April 2010, the LTN-101 a
Page 238 and 239: did not illuminate. The new OEB (A3
Page 240 and 241: modifications were made to its guid
Page 242 and 243: this advice. At the time of the fir
Page 245 and 246: APPENDIX A: VERTICAL ACCELERATIONST
Page 247 and 248: APPENDIX B: FLIGHT RECORDER INFORMA
Page 249 and 250: APPENDIX C: POST-FLIGHT REPORTThe f
Page 251 and 252: - 231 -
Page 253 and 254: - 233 -
Page 255 and 256: APPENDIX D: OTHER DATA-SPIKE OCCURR
Page 257 and 258: Occurrence on 27 December 2008Overv
Page 259 and 260: Figure D2: FDR data for the 27 Dece
Page 261 and 262: ADIRU informationADIRU 1 was the sa
Page 263 and 264: APPENDIX E: ADIRU TESTINGTest plan
Page 265: Visual inspectionsExternal visual i
Page 269 and 270: Unit 4167 passed 2,223 of 2,272 tes
Page 271 and 272: dwells (sustained testing at a fixe
Page 273 and 274: APPENDIX F: AIRCRAFT LEVEL TESTINGI
Page 275 and 276: APPENDIX G: ELECTROMAGNETIC RADIATI
Page 277 and 278: cannot be ‘decoded’ by the rece
Page 279 and 280: APPENDIX H: SINGLE EVENT EFFECTSNot
Page 281 and 282: Factors affecting SEE exposureAn ai
Page 283 and 284: portions of memory are constantly b
Page 285: Depending on the form of EDAC, sing
Page 288 and 289: • crew actions: the passenger’s
Page 290 and 291: The questionnaire respondents were
Page 292 and 293: was centred across the passenger’
Page 294 and 295: Previous occurrencesThe seat belt m
Page 296 and 297: Australian turbulence eventsThe mos
Page 299 and 300: APPENDIX L: SEAT BELT USE IN ROAD V
Page 301: Table L1: Recent seat belt use rate
Page 304 and 305: US Federal Aviation AdministrationT
Page 307 and 308: APPENDIX N: SOURCES AND SUBMISSIONS
Page 309 and 310: Hanson, RJ 1987, Conducted electrom
Page 311 and 312: 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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