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

Abstract

Flying a helicopter requires greater coordination than flying a fixed-wing aircraft, because the pilot is required to apply force simultaneously to three controls: the cyclic, collective, and pedals. There has been one study of pilot applied forces during helicopter flight, but this investigation did not examine muscle activity patterns. The aim of this study was to examine the muscle activation patterns and control forces of helicopter pilots during routine maneuvers. METHODS: Six pilots were tested in a UH-1 h Iroquois helicopter. The maneuvers involved hovering, winching, under-slung loads, a constant rate turn, and a high-speed valley turn. Variables recorded were pilot applied forces and electromyographic activity (EMG). Multivariate analysis of variance was used to test for differences between maneuvers. RESULTS: 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 more than 25% of a maximum voluntary contraction for any maneuver. The greatest magnitude of EMG activity was recorded from vastus lateralis during high-speed valley turns. There were significant differences between the EMG activity of left triceps, right triceps, and right deltoid for some maneuvers (p < 0.05). CONCLUSION: The control forces required to fly a helicopter during routine maneuvers are small. The levels of muscle activation associated with pilot applied forces are also low, but are similar to those reported during routine maneuvers in a fast-jet flight simulator.