As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 223 - EXHAUST FUMES FILL THE CABIN WHEN USING APU BLEED AIR USING LT OR RT PACK. SELECTED RT PACK AND RAM AIR, WITH APU OFF, FUMES CEASED. THIS CLEARS OUT THE EXHAUST FUMES FROM THE CABIN. TRANSFERRED TO DMI NR 0021799-1 CAT ''C''. PER MEL 49-1-2. (M)