During the course of troubleshooting a grinding noise originating with movement of the flaps, the following crack was noted (picture attached). The grinding was a result of asymmetric placement of washers on the flap hinges causing impingement between the outboard section of the flap and the wing. Correct clearance between the flap and wing was obtained once the washers were correctly re spaced.
Inspection of the wing assembly revealed the separation of the the dorsal wing skin and the wing just outboard of the flap. The picture shows the current extent of the crack. How should this be addressed and of what urgency; what is the likelihood of propagation and possible consequences of a crack in this location?
Thanks