Noise Analysis of a Twin Piston Engine Aircraft Jurica IVOŠEVIĆ a , Ivan MIHALINĈIĆ a and Tino BUCAK a a Faculty of Transportation and Traffic Sciences, Department of Aeronautics, University of Zagreb, Vukelićeva 4, 10000 Zagreb, HRVATSKA, e-mail: jurica.ivosevic@fpz.hr , icomihalin@gmail.com , tino.bucak@fpz.hr ABSTRACT In aviation; the airports and the airline industry, a great number of people is exposed to high intensity noise. External aircraft noise, which is precisely defined and standardized through international regulations, adversely affects the ground crew while internal (cabin) aircraft noise significantly affects communication and comfort of the crew and passengers. A number of internal and external noise measurements have been undertaken on two G/A twin piston engine aircraft, Piper PA-44 Seminole and Piper PA-34 Seneca , and some of the results are presented and discussed, along with few possible methods of noise reduction.