Flutter envelope expansion is one of the most critical types of developmental flight tests, particularly for high-speed military aircraft. The regions that present the most dangerous flight profiles are those test points in the negative PS realm of the flight envelope. These points develop into high-speed dives and require an accurate predictive model to prevent possible testing accidents. As a flight test is conducted, several conditions such as aircraft weight and ambient air temperature can change, causing a drastic shift in the excess power profiles resulting in significant alteration in the test conditions. Using a dive planning model, a number of parameters were analyzed to determine the sensitivity to variations in data. This sensitivity analysis provided detailed information regarding the parameters that are most effected by minor variations in test conditions. The goal of this study was to improve the safety of flight test programs and increase test efficiency by improved test planning and execution.