What was found
FLIGHT ATTENDANTS REPORTED A DIRTY SOCK SMELL ON APPROCH INTO PHL CAUSING DIZZINESS. AFT F/A WENT ON OXYGEN FOR REMAINDER OF THE FLIGHT. MAINTENANCE REMOVED AND REPLACED THE APU, THE LEFT PRIMARY HEAT EXCHANGER AND NR 1 & 2 PRECOOLER EXCHANGERS. HONEYWELL TEARDOWN REPORT INDICATES THE APU SHOWED SIGNS OF INGESTION. ALTHOUGH A POSITIVE LEAK WAS NOT IDENTIFIED, THE LOAD COMPRESSOR / SEAL AREA WAS WET WITH OIL EXTERNALLY AS WAS THE SCROLL HOUSING, AND OIL WAS FOUND IN BLEED SYSTEM.