I have managed to improve the quality to 6.318E-2 by creating an square box in between the gaps and unite it with the aircraft to close the gaps. I will continue to work on improving the gaps. However I can't seem to update the mesh now as the software will say that "The Process suffered an unhandled exception or ran out of usable memory". I can't seem to highlight the problematic geometry also to isolate the problem.
May I know how can i troubleshoot this problem?
Attached is the screenshot of the meshing stage for your review.
Figure 1. Orthogonal Quality
Figure 2. The Mesh when I tried to update the geometry