As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHTDECK FILLED UP WITH SMOKE (ON GROUND)THIS HAPPENED WHILE ENGINES WERE NOT RUNNING, APU WAS RUNNING WITH APU BLEED AIR ON. SMOKE CAME FROM L AND R WEMAC. REMOVED AND INSTALLED APU IAW MM 49-10-00. PERFORMED OPS CHECK OF APU ALL CHECK GOOD IAW MM 49-10-02 OK TO INSTALL UPPER & LOWER APU ACCESS PANELS INSTALLED UPPER & LOWER APU ACCESS PANELS.