Helicopters for logging : characteristics, operation, and safety considerations
P. M. Stevens (Author), Edward H. Clarke (Author), Pacific Northwest Forest and Range Experiment Station (Portland, Or) (Issuing body), United States Department of Agriculture, United States Forest Service
"This report presents a general overview of factors relevant to the productive and safe use of helicopters for timber harvesting, with emphasis on candidate helicopters and their characteristics."
Print Book, English, 1974
United States Department of Agriculture, United States Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, Oregon, 1974