2003 IMTA Proceedings - International Military Testing Association

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Fig. 6b: Heading performance of the volunteer (as RMS error in degrees) for each of the four
turbulence levels (none, light, moderate, and severe) for the CD (left group of histograms), OZ
(middle group of histograms) and OZ while reading (right group of histograms).
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With CD, performance degraded with increased turbulence, as shown by the RMS error
values on the y-axis; the larger the RMS, the poorer performance. Note that for the task of flying
with CD, the participants did not perform the secondary reading task; their only responsibility
was to control the aircraft. The secondary task of reading was simply impossible for the
participants with CD. Performance with OZ without the secondary task replicated Experiment 1,
but the participants were much more experienced.
ANOVAs for altitude (F = 4.542, MSe = 2480.073, df = 11, 308; p < 0.0001) and heading
(F = 38.8159, MSe = 576.668, df = 11, 308; p < 0.0001) and Post Hoc tests (LSD) showed that
while turbulence did significantly degrade performance with CD, it did not degrade performance
with OZ with or without the additional reading task. This difference between OZ and CD for
turbulence is clearly shown in Figure 6. Particularly noteworthy is the absence of a statistically
significant difference between OZ flight performance with and without the secondary the reading
task. This finding is also visually evident in Figure 6.
45 th Annual Conference of the International Military Testing Association
Pensacola, Florida, 3-6 November 2003