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

QAR dataOverall, the QAR recorded 46 spikes in AOA 1 during the period from 0440:26 towhen the aircraft landed. No spikes or problems were evident at any time for theAOA 2 values.Although not exact, there was a reasonable correlation in the timing between theAOA 1 spikes recorded by the QAR and the FDR. The FDR and QAR systemswere not synchronised, so the time at which both recorders sampled the AOAvalues was not always the same. As a spike may have affected one ADIRU outputvalue but not the next, it was possible that the FDR may have recorded a spikewhen the QAR did not, and vice versa.Even when the FDR and QAR recorded AOA 1 spikes at about the same time, theywere not always the same value. This difference was due to the two recordershaving a different range and resolution for AOA. In short, an AOA value of morethan 45° was recorded incorrectly by the QAR as a value of about 45° less than theactual value. For example, a 50.625° spike would be recorded by the QAR as avalue of 5.801°.CVR dataThe signal path for the CVR was different to that for the FDR, so the timing of thestall warnings recorded by the two systems would not be exactly the same.Allowing for this difference, the CVR and FDR data were in general agreement.The timing of the stall warnings recorded by the CVR was also generally consistentwith the intermittent AOA spikes recorded on the FDR.1.11.5 Data associated with the pitch-down eventsElevator movementsThe range of elevator movement was +15° (nose-down) to -30° (nose-up) and theelevators could move rapidly. Both the left and right elevator positions wererecorded on the FDR, and each was sampled twice per second.During both pitch-downs, both elevators’ positions changed abruptly in thenose-down direction (Figure 24 and Figure 25). The magnitude of the change forthe first pitch-down was larger, and the rate of change was approximately 15° persecond. The duration of the second pitch-down was slightly longer than the first.The abrupt changes for both pitch-downs were followed soon after by a slowerrecovery period back to normal values.The movements of the left and right elevators were consistent, and the magnitude ofthe elevator movements was also consistent with the magnitude of the aircraft’spitch changes.- 42 -