As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING A PRESSURE DECAY TEST IAW AD2004-21-05, THE COMBUSTION TUBE WOULD NOT AINTAIN PRESSURE AND AIR LEAKING WAS NOTED. INVESTIGATION FOUND A .75 INCH LONG CRACK IN THE AFT END OF THE COMBUSTION TUBE NEAR THE RADIUS. CRACK MAY HAVE BEEN CAUSED BY STRESS INDUCED WHILE FORMING THE END CAP ALONG WITH NORMAL HEATING AND COOLING OF THE HEATER. HEATER HAD 98 HOURS SINCE LANST PRESSURE TEST. A FACTORY REBUILT UNIT WAS INSTALLED AND AIRCRFAT RETURNED TO SERVICE.