Electronic warfare system detects threats and provides the warnings to crew members for improving survivability. It is composed of Radar Warning Receiver (RWR), Laser Warning Receiver (LWR), Missile Warning Receiver(MWR), Counter Measures Dispenser System (CMDS) against threats, and Electronic Warfare Computer (EWC), which integrates all aforementioned systems. Regardless of maneuvering status of aircraft, CMDS dispenses chaffs or flares based on operation modes (Manual/Semi-Auto/Auto), when there are suspicious incoming threats detected by pilot or radar. The present study deals with issues related to the installation location of CMDS magazines in the rotorcraft. In particular, reaction force and its impact on the airframe structure and thermal operational condition of the CMDS are examined. Further, the operational concept of the CMDS in the KUH (Korea Utility Helicopter) and LAH (Light Armed helicopter) is examined with regard to countermeasures to threats (chaffs and flares).