What was found
UNIDENTIFIABLE ODOR OCCURRED THROUGH ENTIRE DESCENT, UNTIL LANDING. HORRIBLY STRONG ODOR. STRONG OIL, ORGANIC, MUSTY ODOR. FOLLOWED AMM 21-00-01-100-801, STEPS 15 TO 19, STEP 15 LT & RT ENGINE RUNNING, BOTH PACKS OFF & ON, NO OIL CONTAMINATION FROM LEFT & RIGHT, GROUND CONDITIONED AIR CONNECTOR, PERFORMED HIGH POWER RUN OF THE ENGINES, NO ODOR OF OIL NOTED. VISUALLY INSPECTED OZONE CONVERTERS AND RECIRCULATION FAN FILTERS, NO OIL CONTAMINATION. INSPECTED APU COMPARTMENT, NO EXTERNAL LEAK NOTED, OIL WAS FULL. REMOVED GROUND PNEUMATIC AIR CONNECTOR CHECK VALVE AND APU BLEED ON, NO CONTAMINATED OIL OR ODOR. INSPECTED BLEED DUCT, DOWN STREAM OF APU, NO OIL CONTAMINATED. OK FOR SERVICE.