A comprehensive noise survey of the S-70A-9 Black Hawk Helicopter

Purpose: This paper reports the results of a comprehensive noise survey of the Sikorsky S-70A-9 Black Hawk helicopter environment and provides an asse ssment of the hearing protection devices worn by Australian Army personnel exposed to that environment. Methods and Results: At-ear noise levels were measured at 4 positions in the cabin of the Black Hawk under various flight conditions and at 13 positions outside the Black Hawk under various ground running conditions using the Head Acoustic Measurement System (Head, GmbH) . The attenuation properties of the hearing protection devices (HPDs) norma lly worn by aircrew and maintenance crews (the ALPHA helmet and the Roanwel l MX-2507 Communications headset) were also assessed. At-ear sound pressure levels that would be experienced by personnel wearing their normal HPDs we re determined at the positions they would normally occupy in and around the aircraft. Conclusion: Results indicate that HPDs do not provide adequate h earing protection to meet current bearing conservation regulations which al low a permissible noise exposure of 85 dB(A) for an 8-h day.