Gravity Problem

Hello guys! Im working on UE4 for my own game. Its been around 2 months since I started this project and I’ve come so far that I built my characters items and etc. but I stuck at some point.

My game is kinda like Space RPG game. And I want to move my characters in ships and also want to move ships around space. but there is some global gravitational problem issue I have.

I put my characters in my ship and set some movement for my ship. when I turn my ship to the UP characters fall down to the back of the ship. I want them to stick on floor. couldnt handle how to fix that and tried a bit. If anybody knows why and how can I fix it? please help Im stuck on this topic for like 3 days.