Dalecki M, Bock O, Guardiera S. Simulated flight path control of fighter pilots and novice subjects at +3 G_z in a human centrifuge. Aviat Space Environ Med 2010; 81:484-8.Background: We have previously shown that subjects produce exaggerated manual forces in +3 G_z. When subjects execute discrete flight path changes in a flight simulator, their performance is less stable in +3 G_z than in +1 G_z. Here we explore whether G_z-related deficits are found with continuous flight path changes. Methods: Novice subjects and fighter pilots sat in a high-fidelity flight simulator equipped with the reproduction of the Eurofighter 2000 cockpit, including the realistic flight stick, and pursued continuous altitude changes of a target airplane in +1 G_z and +3 G_z. Subjects also produced verbal responses in a Stroop task. Pursuit and Stroop tasks were administered alone and concurrently. Results: Flight instability increased in +3 G_z compared to +1 G_z in novices (+46%), but not in pilots (+3%), and even there only during the first minute. Flight performance improved after the first minute in both subject groups. Stroop reaction time was higher in novices (+5.27%) than in pilots (+3.77%) at +3 G_z. Dual-task costs did not differ between groups or G_z levels. Discussion: Deficits of force production in high G_z are largely compensated for when subjects apply forces to produce a continuously changing flight path. This compensation seems not to require additional cognitive resources and may be achieved by using visual feedback. Force production deficits in high G_z seem to have no appreciable effects on flight performance and cognitive load of experienced pilots using a force-plus-displacement stick in +3 G_z. It remains to be shown whether this conclusion extends to purely isometric sticks and to higher G_z levels.