As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NEW FUEL CAP DID NOT VENT. FUEL TANK WAS PARTIALLY COLLAPSED AND SPEWING SOUND WAS COMING FROM THE CAP. CAP WAS TURNED FOR REMOVAL AND WHEN THE INDENTS RELEASED THE CAP, THE TANK POPPED BACK UP IN PLACE. THE CAP DOES NOT SHOW ANY DEFORMATION OR DAMAGE, IT APPEARS NORMAL IN ALL RESPECTS. SUGGEST A TESTING PROCEDURE BE DEVISED BEFORE THESE CAPS ARE INSTALLED.