As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PUNGENT SMELL IN CABIN AND COCKPIT WHEN PACKS ARE POWERED WITH APU BLEED. MAINTENANCE ACCOMPLISHED TASK CARDS 26L0021001 AND 26L00021002, FOUND OIL COKING ON APU LOWER COMPRESSOR SCREEN. RAN ENGINES 10 MINUTES EACH WITH LEFT AND RIGHT PACKS, NO ODOR SMELLED IN CABIN AND FLIGHT DECK. PLACED APU ON MEL FOR FURTHER TROUBLESHOOTING. **SUPPLEMENTAL REPORT WILL BE SUBMITTED** (OPEN)