Military standards and design guidelines do not consider the potential for degradation in the magnitude of force which can be applied by a crewmember or operator as the result of having to perform more than one control input at the same time. In assessing helicopter-control referenced strength capabilities as a part of an overall program to update medical standards for US Army flying duty, 130 subjects performed maximal voluntary exertions on each of the three primary helicopter controls cyclic, collective, and pedals. These exertions were undertaken both as separate inputs to single controls and as simultaneously executed inputs to all three controls. The findings revealed substantial and significant force degradation occurred during simultaneously executed exertions relative to the magnitudes of single control exertions. Cyclic inputs were affected least. The degree of force degradation associated with collective and pedal inputs varied with the particular combinations of direction-of-exertion employed. The resulting patterns for force degradation were similar for the collective and pedal with the extent of degradation being larger for the pedal inputs typically 40-50 percent than for collective inputs typically 20-35 percent. Substantial proportions of the subjects approximately 50 percent of the males and more than 90 percent of the females were unable to consistently attain design-guide force levels MIL-H-8501A, 1961 on all three controls during all of the 16 simultaneously executed exertions.