In some vehicles tonal noise appears in the low frequency range (up to 500 Hz) with high sound pressure level. A typical example is a propeller driven aircraft. Here the excitation frequency is given by the blade pass frequency (BPF) and its higher harmonics. Because the profiles of the blades are optimized with respect to the aerodynamics high noise levels can occur. In order to reach an acceptable noise level (work-security, comfort) in the aircraft cabin passive methods like adding material with high damping or vibration absorbers are used. Especially for low frequency noise, these methods add a lot of unwanted mass to the aircraft. To avoid this, research has been done in the past decades to introduce active noise reduction (ANR). Nowadays, in some smaller passenger aircraft commercial ANR systems are installed. But for large transport aircraft with a high noise level ANR systems are not available for the cargo hold area. In a certain four propeller military transport aircraft the maximum sound level in the cargo hold can reach up to 110 dB(A) without taking into account any noise control treatments. Inside the semi closed loadmaster working station (LMWS) the sound level must be reduced down to 86dB(A). The task is to reach this with an ANR system. In this paper a new method for optimizing the actuator and sensor positions for such a system is described. The transfer functions between all possible actuator and sensor positions are measured in a mock up of the LMWS. Based on this data the minimum number and optimal position of the actuators and sensors are computed. The expected noise reduction and the necessary electrical input are calculated for the configuration obtained. These data are compared with measurement data for the optimal setup implemented into the mock up.