As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FUME EVENT: DESCENDING FROM 23000 FEET TO 10000 FEET. IDLE THRUST. TEMPERATURE -24C SAT TO +1C SAT. UNABLE TO DETERMINE ORIGIN. COCKPIT ONLY. OXYGEN MASKS DONNED. ACCOMPLISHED JOB CARD 26L00021001. FOUND SOURCE OF ODOR TO BE #1 OVEN. REPLACED #1 OVEN PER AMM 25-35-19.