External store safe separation evaluation process implementing the enhanced separation analysis and MIL-HDBK-1763

Abstract

This paper proposes an enhanced external store safe separation evaluation process that integrates multi-fidelity analysis methods (empirical, CFD, and test data) with criteria from MIL-HDBK-1763 to support the evaluation and compliance of external store separations. Safe separation criteria are reviewed across multiple standards and handbooks, including MIL-HDBK-1763, MIL-HDBK-244A, AGARD-AG-202, and AGARD-AG-300 to tailor appropriate limits for typical aircraft and store configurations. The enhanced separation analysis (ESA) constructs vertical and horizontal safe zones using these multi-fidelity methods. To validate the process, the GBU-31 bomb released from an F-16 aircraft is analyzed. Evaluation criteria are based on airborne weapon compatibility and safety standards. CFD simulations are conducted to predict the trajectory of the GBU-31 under aerodynamic effects caused by the F-16 fuselage, an external fuel tank, and an adjacent AIM-9M missile. The simulations use accurate input derived from wind tunnel experiments and static test data of the ejection unit. The enhanced evaluation identifies motion trends and potential collision risks by tracking critical points on the GBU-31. These critical points must remain within defined vertical and lateral safe boundaries to ensure a collision-free release. The proposed evaluation method proves to be effective and reliable in analyzing complex separation phenomena. It enhances understanding of weapon-aircraft interactions and reduces the need for extensive flight testing during the development of new or upgraded munitions by leveraging tailored criteria and high-fidelity simulations.