Cabin noise exposure assessment of the Royal Canadian Air Force CH-147F helicopter through flight testing

Military helicopter aircrew are often required to spend long hours at their station in the cockpit or the cabin to perform various duties. For example, Canadian aircrews are routinely known to spend over six hours per day in order to perform operations that include pre-flight, flight, and post-flight tasks while wearing helmets for hearing protection. The objective of this particular measurement campaign was to measure the cabin noise levels of the CH-147F helicopter at selected aircrew stations through representative flight operations and to determine the aircrew noise level exposures inside the aircraft during flight missions. This paper focuses on the performance evaluation of existing hearing protection solutions used by the Royal Canadian Air Force (RCAF) personnel at selected aircrew workstations, based on noise level measurements on a RCAF CH-147F Chinook helicopter during representative flight conditions. The study allowed the selection of an optimal hearing protection solution for CH-147F helicopter aircrew. Additionally, the present study provided a clear insight on the difference between open and closed door flight mission segment noise environments as well as specific behavior related to various flight conditions. A number of recommendations were provided to the RCAF to mitigate hearing damage risk in diverse mission situations.