So, this happened on last longer flight.
I could see it already in the air, but since it was just a flapping rubber seal, didn't really think it was necessary to get on the ground. Basically - it's a gap seal between the nacelle and the wing that's come loose (not sure entirely why there's a gap here at all, but it's designed that way).
Anyway, on the right engine this gap was sealed with rubber seal that looks very much like a seal you would find around a car door etc. This was glued in place, came loose at the tail and and like a whip in the airstream, it smashed against the paint of the nacelle and underside of wing. You can see what a mess the rubber compound left behind. Anyway, on the left hand side, that same gap is sealed with what looks like a silicon rubber sealant. As you can see, it's also not in the best of shape, but it won't come off in the way this other seal did.
My question is - which is the correct way to seal this gap? Is it with silicon-like compound like on the left, or with a glue-in-place rubber seal like on the right?
