As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STRONG SMELL OF FUEL IN THE COCKPIT AT CRUISE ALTITUDE. WHEN ON THE GROUND STARTED THE APU WITH THE MECHANIC IN THE AFT EQUIPMENT BAY. FUEL BEGAN POURING OUT OF A FUEL LINE THAT WAS NOT TIGHTENED DOWN. IN 1 MINUTE OF RUNNING THE APU HAD APPROXIMATELY 2-3 INCHES OF FUEL IN THE AFT EQUIPMENT BAY. THIS WAS UNCONTAINED FUEL AND VAPORS. FOUND APU PO CONTROL FUEL LINE LEAKING. RESECURED B-NUT ON FUEL LINE IAW AMM 45-31-01.