Ray tracing inside a concave structure is known to become complex due to multiple reflections, transmission and diffraction. Although the image method yields precise point-to-point solutions, it cannot be always used for complex concave environments such as curvatured concave enclosures. A refined ray tracing method is developed here, and implemented inside an aircraft cabin. Since image method is not available for the aircraft cavity, the validation for refined ray tracing is obtained through a lossy cuboid for which the image method is readily available. Finally the ray-path details inside a generic aircraft cabin are generated using refined ray tracing for RF field computation.