What was found
DURING PRESSURE DECAY TESTS OF ELECTRO SYSTEMS JAN-AERO HEATERS, PN FR10E21-EL, WE HAVE DISCOVERED PRESSURE LEAKS IN THE CERAMIC COATED COMBUSTION TUBES. THIS HAS OCCURED ON 4 SEPARATE OCCATIONS. IT SHOULD BE NOTED THAT THE PERIODIC PRESSURE DECAY TEST REQUIRED BY AD 96-20-07 (DOES NOT APPLY TO) HEATER SERIES B3500 WITH (CERAMIC COATED) COMBUSTION TUBES. ALTHOUGH THE PERIODIC PRESSURE DECAY TEST IS (NOT) REQUIRED BY AD 96-20-07 FOR CERTAIN HEATERS WITH (CERAMIC COATED) COMBUSTION TUBES. MM CONTINUES TO RECOMMEND PERIODIC PRESSURE DECAY TEST OF THE HEATER COMBUSTION TUBES REGARDLESS OF THE HEATER CONFIGURATION.