As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DUCT IS LOCATED IN THE APU SUPPLIED AIR SYSTEM USED FOR GROUND AIR CONDITIONING AND ENGINE START. THIS DUCT FAILED ON THE GROUND PRIOR TO ENGINE START. IT APPEARS THE DUCT COUPLING 'UNSWAGED' FROM THE DUCT CAUSING LOSS OF MANIFOLD PRESSURE.