The present invention increases the survivability of a helicopter by prioritizing a threat engagement sequence for a laser-based countermeasure system based on the determined relative lethality of each detected visually trained threat (e.g., small arms fire). The system and method defines a plurality of threat effectiveness merit factors, or lethality factors, that are determinable from available helicopter navigation and sensor data, to quantify the danger associated with each detected threat. The system and method then combines the defined lethality factors using a mathematical function, such as a merit function, to numerically quantify the level of threat posed by each threat. The calculated threat values for each of the detected threats are compared to prioritize the threats for engagement by a laser-based countermeasure system, such as a Visual Acquisition Disrupter (VAD) system.