Acoustic evaluation of the AGUSTA 109A Helicopter in compliance with the proposed ICAO Annex 16/Chapter 8 regulations Noise measurements on the AGUSTA 109A helicopter were performed in order to determine the effective perceived noise levels (EPNL) in compliance with propos... WR Splettstoesser,SR ...
1.1.2 In time, the speed of aircraft increased and engine noise levels dropped with the development of newer generation turbine engines. Aircraft simply became too quick and too quiet for birds to sense and avoid. Birds inadvertently became a serious threat to aircraft safety as strikes became ...