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

APPENDIX F: AIRCRAFT LEVEL TESTINGIn May 2009, an assessment of the aircraft (VH-QPA) was conducted tocharacterise the electromagnetic environment around air data inertial reference unit(ADIRU) 1 during normal operation and in relative proximity to potential sourcesof electromagnetic interference (EMI). 214 Measurements included the following: 215• ‘Conducted’ bulk current 216 measurements were taken in the cable bundlesconnected to ADIRU 1 during ground and flight testing, and in the cable bundlesconnected to ADIRU 3 during ground testing. The measurements characterisedthe current in the cables at frequencies between 10 kHz and 500 MHz.• ‘Radiated’ electric fields measurements were taken at a location immediately tothe rear of ADIRU 1 during ground and flight testing, and immediately to therear of ADIRU 3 during ground testing. These measurements characterised theelectric fields near the ADIRUs at frequencies between 500 MHz and 7 GHz.Other frequencies could not be tested due to limitations of the test equipmentavailable. Measurements from the sensors were logged by computer.The measurements were taken in the following stages:• Measurements taken with the aircraft on the ground and without any aircraftpower applied, including with several mobile phones being operated on boardthe aircraft while the measurements were taken.• Measurements taken with the aircraft on the ground and with auxiliary powerunit (APU) power applied.• Measurements taken with the aircraft in flight, including with various aircraftsystems in operation (such as the passenger in-flight entertainment system andvarious radio communication systems).The assessment flight was conducted on 17 May 2009. The aircraft departed fromSydney, New South Wales, flew to Learmonth, Western Australia, and operated inthe vicinity of the Harold E. Holt Naval Communication Station near Learmonth,Western Australia, for about 2 hours (Figures F1 and F2). The aircraft was flowndirectly over the facility in a northerly and easterly direction, along a 90° quadrantat a constant distance to the north-west of the facility, past the facility at a tangent,and for some distance along the 7 October 2008 flightpath before returning toSydney. The duration of the flight was 10 hours and 48 minutes, during which bothradiated field and conducted current measurements were observed continuously andrecorded at intervals.All aircraft systems, including the ADIRUs and electronic flight control system(EFCS), operated normally throughout the testing activities.After the flight, the flight data recorder (FDR), quick access recorder (QAR) andlogged test data were analysed. The analysis did not reveal any anomalous results.214215216At the same time, a range of other tests and checks of the wiring and configuration associated withthe aircraft’s ADIRUs was also undertaken (section 1.12.5).Refer to Appendix G for an explanation of technical terms relating to EMI.Bulk current measurements are taken from an entire cable bundle at once, as distinct frommeasurements taken from each cable individually.- 253 -