2003 IMTA Proceedings - International Military Testing Association

Procedure: Data collection consisted of the participant flying one display for 3000
simulator cycles, which was about three minutes, then flying the other display for 3000 cycles,
alternating between the displays for from one to two hours. Data collection for both displays
continued for a given turbulence condition until the participant felt that the flight performance
had stabilized on both displays. Whether OZ or CD began the run was determined randomly.
The condition without turbulence was completed first. This condition was followed by the low
turbulence, followed by the moderate turbulence followed by the extreme turbulence. One
turbulence level per day was collected per participant. Several days could intervene between
data collection. The two participants worked as a pair, one serving as the experimenter for the
other.
Data Reduction: Flight performance was scored as root mean square (RMS) error. RMS
error was chosen because it combines two different aspects of performance into a single metric-the
variability of the observed performance relative to a target performance, which itself can be
displaced from the average performance (1, 14, 31). RMS errors for both heading (in degrees)
and altitude (in feet) were calculated from 300 successive simulation cycles, each cycle
providing a heading and an altitude RMS. A trial consisted of 10 heading and altitude RMS
error scores, summarizing the 3000 successive simulation cycles. For a trial, the 10 RMS scores
for heading and 10 RMS scores for altitude were further reduced to a mean altitude RMS error
and mean heading RMS error.
Results
To illustrate how the data were reduced for analysis, Figure 4 plots, as a function of time,
flight performance data of individual trials obtained for a single condition and participant. Panel
(a) shows RMS altitude error in feet and panel (b) shows RMS heading error in degrees under
the condition of light turbulence. Each dot displays RMS error for 300 simulator cycles obtained
with OZ; the line connects comparable RMS errors obtained with CD. The horizontal axis
shows the that data collection duration for this run lasted 66 minutes (33,000 simulator cycles).
Before this run, the participant had about 45 minutes of flight experience obtained during the no
turbulence condition. Data from the other participant were essentially identical to those shown
in the Figure.
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45 th Annual Conference of the International Military Testing Association
Pensacola, Florida, 3-6 November 2003
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