Skid Mount to Main Frame
With the panel aft of the fuel cell panel removed you can see the rear connection to the fuel cell and the attachment of the rear cross-tube saddle mounts to the airframe.
The photo attached shows the saddle mounts are working.
This is common as oil collects in this area as you can see. On earlier airframes these panels may be riveted down, there was an early military message ( late 60’s early 70’s ) to take out the rivets.
Install nut-plates in the corners and every other hole and install flush rivets in the remaining holes from the bottom.
We check these at once a year along with the lower fuel cell panels. Alcohol is good for flushing out the oil.
There are four panels just forward of the aft cross-tube, these collect oil and dirt.