Loose Rivets.
Finally someone pointing out the obvious here. thanks!
The Good old Chief Dr in Oslo , now long retired showed no mercy on anyone foolish enough to tick that box.
Grounded until such time he was 110% sure it did not occur again.
ie : He had to know why!
It was after all his responsibility and business.
I hope proper tests was taken and that the Fo recovers and can fly in the future.
If medically fit at ALL times.
Regards
Cpt B