In-Flight Control Force Inputs for the US Army UH-1 Helicopter during 'Hydraulics-On' and 'Hydraulics-Off' Approaches and Landings,
ARMY AEROMEDICAL RESEARCH LAB FORT RUCKER AL
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There is little information available regarding the magnitude of force input to helicopter controls under emergency conditions. Accordingly, 12 male US Army aviators each flew six normal and six simulated emergency condition hydraulics-off approaches and landings in an Army JUH-1H utility helicopter. Because there existed concern that forces applied might vary substantially with flight experience, the aviators who participated in the study were solicited from two groups differing widely in the number of hours flown. The three principal controls of the aircraft cyclic, collective, and pedals were strain-gage instrumented. The outputs recorded during the last 60 seconds of flight prior to each touchdown were studied. Analyses of variance undertaken on the means of the forces recorded during successive 5-second intervals revealed significant differences in the magnitude of the forces applied as a function of hydraulics condition and time-to--touchdown i.e., forces differentially increased as touchdown neared during hydraulics-off approaches. With the exception of inputs in the downward direction on the collective, the descriptive statistics showed the overall mean and median forces for both groups of aviators to be lower than previously reported helicopter-control-referenced maximal 4-second strength capabilities of small Army males and females.
- Personnel Management and Labor Relations
- Military Aircraft Operations