What was found
RECEIVED HEATER CORE FROM CUSTOMER. THE COMBUSTION TUBE END PLATE HAS TWO VISUAL CRACKS. ONE AT THE TWO O’CLOCK POSITION AND ONE AT THE SEVEN O’CLOCK POSITION. THIS HEATER IS THE (FR) SERIES THAT HAS THE CERAMAKOTE COMBUSTION TUBE WITH NO AD AGAINST IT. BY LOOKING AT THE HEATER SN THIS HEATER WAS MFG IN MARCH, 1999. CAUSE OF THE CRACK IS PROBABLY CAUSED BY METAL FATIGUE DUE TO TIME IN SERVICE OR RUNNING THE HEATER TOO HOT. THERE IS NOTHING THAT CAN BE DONE TO PREVENT THESE CRACKS. ALL AIRCRAFT HEATER COMBUSTION TUBES AT SOME POINT IN TIME ARE GOING TO FAIL/CRACK. A PRESSURE TEST OF THE COMBUSTION TUBE WILL FIND THESE FAILURES.