Aircraft control forces and EMG activity in a UH-1H Iroquois helicopter during routine maneuvers

Flying a helicopter requires greater coordination than flying a fixed-wing aircraft, because the pilot is required to apply force simultaneously to th ree controls: the cyclic, collective, and pedals. There has been one study of pilot applied forces during helicopter flight, but this investigation di d not examine muscle activity patterns. The aim of this study was to examin e the muscle activation patterns and control forces of helicopter pilots du ring routine maneuvers. Methods: Six pilots were tested in a UH-1 h Iroquoi s helicopter. The maneuvers involved hovering, winching, under-slung loads, a constant rate turn, and a high-speed valley turn. Variables recorded wer e pilot applied forces and electromyographic activity (EMG). Multivariate a nalysis of variance was used to test for differences between maneuvers. Res ults: Significant differences between the maximum forces recorded from each control across all maneuvers were recorded (p < 0.05). The greatest pilot applied forces were recorded from the pedals. No muscles were activated mor e than 25% of a maximum voluntary contraction for any maneuver. The greates t magnitude of EMG activity was recorded from vastus lateralis during high- speed valley turns. There were significant differences behween the EMG acti vity of left triceps, right triceps, and right deltoid for some maneuvers ( 0 < 0.05). Conclusion: The control forces required to fly a helicopter duri ng routine maneuvers are small. The levels of muscle activation associated with pilot applied forces are also low, but are similar to those reported d uring routine maneuvers in a fast-jet flight simulator.