What was found
OVER LAST 12 YEARS AND 500 HOURS OPERATING TIME N1975T HAS EXPERIENCED 5 FAILURES OF THE PUMP PN RAP215CC-9. IN EACH CASE EXCEPT LAST INSTALLATION A PROPERLY LICENSED FAA TECH FAILED TO FOLLOW RAPCO INSTALLATION INSTRUCTIONS INCLUDED WITH PUMP. THIS LEAD TO PREMATURE PUMP FAILURES DUE TO OIL INGESTION THROUGH PUMP DRIVE SHAFT SEAL. LAST MECHANIC SHOWED ME SEAL WAS SLIGHTLY BENT DUE TO INCORRECT INSTALLATION 12 YEARS AGO. NEW PUMPS QUICKLY BECAME CONTAMINATED WITH OIL WHICH ACTED LIKE ADHESIVE ON PUMP VANES. THIS PREVENTED THEM FROM EXTENDING AT LOW RPM. PROPER VACUUM WOULD NOT OCCUR UNLESS THE ENGINE WAS RUN UP TO ABOUT 2000 RPMS. THEN THE VACUUM WOULD SUDDENLY JUMP FROM ALMOST ZERO TO ACCEPTABLE LIMITS. THIS WAS DUE TO HIGH CENTRIPETAL FORCE ON PUMP VANES THAT OVERCAME ADHESIVE FORCE OF OIL CONTAMINATION. SOMETHING SYSTEMICALLY WRONG WHEN 4 OUT OF 5 FAA LICENSED INSPECTORS/MECHANICS CAN NOT READ INSTALLATION INSTRUCTIONS AND INCORRECTLY INSTALL A VACUUM PUMP THAT HAS A DEFECTIVE DRIVE SHAFT SEAL! THIS CAN CAUSE THE FAILURE OF THE DG AND AH DURING IMC FLIGHT WHICH FAA STATISTICS HAVE LINKED TO FATAL ACCIDENTS EACH YEAR! IN ADDITION THE LAST 11 OUT OF 12 ANNUAL INSPECTIONS FAILED TO NOTICE UNACCEPTABLE VACUUM PRESSURE! I URGE THE FAA TO ISSUE SERVICE BULLETINS AS WELL AS AN AD ON THE RAPCO PUMP WHICH SELF DISTRUCTS IN AN OILY ENGINE COMPARTMENT. I BELIEVE THIS IS THE FAA HOTLINE REPORT NUMBER I FILED AAE-EHL-20240304-973.