Aircraft noise affects crew communication and comfort and continued exposure can lead to hearing loss if the personnel hearing protection is insufficient or improperly worn. Therefore, evaluation of the noise levels experienced by helicopter aircrew is essential in order to select optimum hearing protection solutions to enhance aircrew safety and reduce the potential for health issues in the long term. Cabin noise exposure of crew members was investigated in the NRC Bell 412 helicopter, the civilian variant of the CH-146 employed by the RCAF and the results were compiled with regard to the acoustic specifications of hearing protection devices in use during missions. The tests were conducted in accordance with standard test procedures ISO 5129:2001 “Acoustics - Measurement of sound pressure levels in the interior of aircraft during flight” and MIL-STD-1294A “Acoustical noise limits in helicopters”. Acoustic sound pressure levels (SPL) were recorded in the aircraft interior at different crew station locations during various flight conditions.