As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FUEL FILTER HOUSING ATTACHMENT FLANGES CRACKED. THIS IS THE FIFTH FILTER HOUSING THAT HAS CRACKED SINCE 01/30/99, THREE ON N86 AND TWO ON N87. AFTER INVESTIGATION IT WAS CONCLUDED THAT THE FUEL FILTER HOUSING FAILURES ARE THE RESULT OF FUEL CONTROL UNIT OVERPRESSURE CAUSED BY THE MALFUNCTION OF AN INTERNAL ULTIMATE RELIEF VALVE.