As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE AND ODOR IN CABIN. SMOKE DUE TO INGESTION OF HYDRAULIC FLUID INTO APU AIR INLET. LOOSE B-NUT ON RETURN LINE FOR RUDDER LOWER POWER CONTROL UNIT DETERMINED TO BE SOURCE OF LEAK. B-NUT TIGHTENED, OIL RESIDUE CLEANED UP AND PNEUMATIC AND AIR CONDITIONING DUCTING PURGED USING HIGH TEMPERATURE AIR.