As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
COCKPIT SMOKE: AFTER STARTING THE APU, THE COCKPIT FILLED WITH SMOKE WHEN THE THE APU BLEED VALVES WERE OPENED. WE INSPECTED THE INTERIOR AND EXTERIOR OF THE TAIL CONE BUT FOUND NO OBVIOUS SOURCE OF THE SMOKE. // SIGNOFF // REMOVED APU P/N 3800785·1 S/N P-908 INSTALLED REPAIRED SERVICEABLE APU P/N 3800785-1 S/N P-783 SUPPLIED BY CUSTOMER NETJET TSN 3027 CSN 4265, OPERATIONAL AND LEAK CHECK SUCESSFUL WORK DONE IAW 680A 'AMM 49-10-00