As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AERONAUTICAL ACCESSORIES PC SAFETY VALVE KIT, STC SE327AT, STA SE93-4. UPON REMOVAL FOR OVERHAUL THE ACTUATING KNOB WAS FOUND SHEARED AND HELD IN PLACE BY THE RETAINING CLIP. THE KNOB WOULD NOT HAVE FALLEN HOWEVER THE VALVE ITSELF WAS NO LONGER HELD IN PLACE OTHER THAN BY FRICTION. THE VALVE COULD HAVE FALLEN OUT CAUSING A SUBSTANTIAL AIR LEAK.