It's probably a wing collision issue my dude,
Open XML and on the disableAircraftCollisions part write true

that should fix it

@Metalsaurusnerf
All wings other than the StructualWing are used to shift from the base of the wing when a force is applied.
(Just like the left wing of the plane in your photo is out of alignment.)

@nagisa thanks whats wing deflection?

Here
I was able to solve the problem by disabling the wing deflection. But I still don't know the detailed cause of the problem.

@Gluck I’ve tried that but it didn’t work the photo in the post links to the plane so you could see the problem

Sometimes the attachment points get messed up, it should be fixed by replacing the right wing, then mirroring. If problems persist, try replacing the wing from a different attachment point.
@Metalsaurusnerf

I hate simpleplanes physics I don’t know how to fix the problem

I know what the problem is it’s the wing inside the fuselage on the left not working thing is I don’t know how to fix it I tried mirroring

The picture is clickable

@ACEPILOT109 drag doesn’t seem off

@Metalsaurusnerf
just check it make sure there isnt more drag on one side just cause SP physics even if they are the exact same

@ACEPILOT109 both sides are mirrored so they should be

@Metalsaurusnerf idk whats up
did you look at the drag?

@ACEPILOT109 very helpful

mnmmmmm