Vertical Hinge Pin Installation
The picture above shows that the retainer for both the upper and lower vertical fin hinge pin was installed incorrectly.
The photo of the retainer shows the retainer installed incorrectly with the rounded bead out board.
Installed this way allows the pins to bypass the retainer.
In this case the photo below shows what can happen when the upper pin is not retained.
Luckily in this case there was no damage, but you can see what could have been.