Cabin Noise Assessment of the RCAF CH-149 Cormorant Helicopter through Flight Testing

摘要

Royal Canadian Air Force (RCAF) CH-149 Cormorant helicopter aircrew are often required to spend long hours performing flight duties in various flight conditions to complete Search and Rescue (SAR) missions. The RCAF aircrew are often exposed to a diverse range of operational activities included exiting the aircraft seat in order to perform various in-flight procedures. A noise survey of the RCAF Cormorant helicopter has been performed to characterize the noise environment of the helicopter platform. The objective was to assess the noise environment of the CH-149 helicopter throughout representative flight conditions at a selection of cabin and cockpit crew locations to enable quantitative evaluation of the aircrew noise exposure in SAR missions. Noise measurement results indicated that the sound pressure levels varied considerably with flight conditions and the opening status of the cabin doors. The highest A-weighted sound pressure levels in the helicopter cabin reached 107 dB(A). Based on the insertion loss performance of the RCAF SPH5-CF flight helmet, the aircrew with a properly fitted flight helmet may experience overall sound pressure levels in excess of 85 dB(A) in the doors open configuration and 79 dB(A) in the doors closed configuration at 120 knots steady level flight condition.