Abstract: This paper proposes a methodology for the design and development of damage estimation and assessment models based on the weaponeering concepts to estimate and assess the damage caused to ground-based targets from air-borne platforms. These models are used to assess the effectiveness of ground attack weapon systems in an air-land battlefield scenario. A software package called Over Target Requirement Estimation System (OTRES) has been developed based on the proposed methodology which considers a number of factors such as weapons characteristics, target parameters, terrain, target vulnerability, weapon effects, munitions delivery errors, damage criteria, probability of kill, weapon detonation reliability to estimate the damage to a ground target. This estimate is used to generate course of actions and the planner selects one of them by corroborating with other environmental factors, enemy defences and intelligence inputs. The selected course of action (mission plan) is gamed against the perceived threat using the Air Warfare Simulation System (AWSS) test-bed which calculates the attrition to air missions by ground-defence systems deployed to defend a vulnerable area / vulnerable point (VA/VP), and the results are analysed to derive training lessons from the simulator.