In an aircraft the weight of the active noise control (ANC) system is a critical property. Therefore one aims at minimizing the number of microphones and loudspeakers. In doing so, only a reduced number of sensors and actuators may be used. Only recently has the relevance of placing sensors and actuators, in achieving a good global active noise control system, been considered. In this paper we will present two stochastic search methods for optimally placing the ANC-system -loudspeakers and -control microphones in a turboprop SAAB2000 aeroplane. The problem of optimal placement has not yet been showed to be analytically solvable. The number of possible configurations is large, indicating that stochastic search methods are strong candidates. In this work we show that genetic algorithms outperform simulated annealing in the case of the studied aeroplane. The method using genetic search also outperforms other known non stochastic methods.