As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PACKS GIVE OFF BURN ODOR WHEN IN "AUTO NORM" WITH TQ AT 65 PERCENT. ALSO DURING DESCENT BURN SMELL NOTICED WITH PACKS IN "NORM" WITH LOW POWER AT N 40 PERCENT. (FLT 1302) REPLACED LEFT ENGINE P2.5/P3 SWITCHING VALVE IN REFERENCE TO P&W MM.