As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
5 MINUTES AFTER TAKEOFF, AIRCRAFT CABIN FILLED WITH WHITE SMOKE. SMOKE SMELLED LIKE OIL. NOT ELECTRICAL. AIRCRAFT RETURNED TO KYIP. SUSPECT APU OIL LEAK CAUSING THE SMOKE AND OIL ODOR TROUBLESHOOTING THE APU TO DETERMINE THE CAUSE AND CORRECTIVE ACTION.