As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU DETECTOR INOPERATIVE B ILLUMINATED. APU FIRE SWITCH DOES NOT ILLUMINATE DURING OVERHEAT/FIRE TEST. ACFT GROUNDED. R & R APU TAILPIPE FIRE DETECTOR IAW AMM REF 26-15-01-000-802/26-15-01-400-802. RESET C/BS, APU FIRE DETECTOR OPS CKS GOOD.