As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN APU AIR AND PACKS SELECTED ON, CABIN AND COCKPIT FILL WITH SMOKE. MAINTENANCE VERIFIED ENG AIR AND PACKS DO NOT SMOKE, JUST APU AIR AND PACKS. DEFERRED APU PER MEL 49-00-1 (C). MAINTENANCE FOUND FLEXIBLE TUBE BETWEEN ANIT-SURGE VALVE AND COMPRESSOR BROKEN, REPLACED TUBE (P/N 4950899). OPS CHECK GOOD.