What was found
LEFT PACK IS PRODUCING VERY STRONG BURNING OIL ODOR. VERIFIED ODOR WITH LT PACK OPERATING. ODOR WAS THE STRONGEST DURING DESCENT. IAW FIM 21-00-01 301 OPENED LT ENG & DISCONNECTED HIGH STAGE DUCT, MOTORED ENGINE. FOUND NO EVIDENCE OF OIL ODOR AT ENGINE. REINSTALLED HIGH STAGE DUCT & CLOSED LT ENGINE COWLING IAW MM 78-31-00-2-3 AT BLOCK IN BOTH LT & RT ENGINE OIL LEVELS AT 18 & APU AT FULL. FOUND APU COMPARTMENT CONTAMINATED WITH GLYCOL. REMOVED APU PNEUMATIC SUPPLY DUCT & INSPECTED FOR CONTAMINATION, NONE NOTED. REINSTALLED DUCT IAW SMP. REMOVED PNEUMATIC SUPPLY DUCTS AT THE INLET TO THE PACK CATALYTIC CONVERTERS & INSPECTED FOR CONTAMINATION, NONE NOTED. REINSTALLED DUCTS IAW SMP. STARTED APU & COMPLIED WITH LEAK CHECK OF REINSTALLED DUCTING, LEAK CHECKS GOOD. PERFORMED PACK BURN, OIL CONTAMINATION REMOVAL, IAW MM 21-00-01-2. NO OIL ODOR NOTED FROM EITHER PACK. ACFT OK FOR SERVICE.