In the aircraft industry, as in most other industries, demand drives most of the change. This is true for all parts of the plane, including the seats. The constant demand for customization of seats in aircrafts has shifted focus to a new type, the oblique-facing aircraft seat. Although the Federal Aviation Administration (FAA) has requirements for front and side-facing seats, it is only recently focusing on development of guidelines for oblique-facing seats, which are defined by seats installed at angles between 18 to 45 degrees. When defining such criteria and guidelines, thoracic and lumbar forces are two important body parts to focus on for load conditions. These two areas, along with four partial injury criteria, namely the Thoracic Trauma Index (TTI), Viscous Criterion (VC), Pelvic Acceleration, and Chest Deflection, are addressed in this study. Using the MADYMO biodynamics software, three oblique-facing seat condition test cases are modeled and simulated with two types of dummies: Hybrid III Anthropomorphic Test Dummies (ATD), and EuroSID-2re. The variation of angles, belt attachments, along with the presence of an arm rest investigated, the results from which can be valuable in arriving at an optimum configuration of the oblique-facing seat for passenger protection. While the Hybrid III results show small variations with the criteria and injury types defined, the EuroSID-2re results show that that the addition of arm rest limits the lateral motion of the occupants in the seat, but could have a large adverse effect on the chest of the passenger on the oblique-facing seat. In the conclusions, injury criteria are explicitly suggested for certification of oblique-facing seats. Overall, it can be stated that the case 2 configuration (45 degrees, two belts, arm rest) would provide optimum protection for passengers on oblique-facing seats.