As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE SERVICING THE OXYGEN SYSTEM, THE HIGH PRESSURE TRANSDUCER SHAFT SEAL BLEW OUT. THIS PRESSURE SWITCH IS PART OF AN STC MODIFICATION TO CERTIFY THE AIRCRAFT AS A SD3-30, . THIS IS SECOND OCCURANCE OF THIS FAILURE. THE FIRST FAILURE WAS ASSUMED TO BE THAT THE WRONG PN, LOW PRESSURE TRANSDUCER HAD BEEN INSTALLED. UPON REPLACEMENT OF THE SECOND UNIT TAE MAXIMUM PRESSURE OF 750 PSIG IS FAR BELOW THE 1800 PSIG SYSTEM PRESSURE.