As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF THERE IS A STRONG DIRTY SOCK ODOR WHICH SEEMS TO DISSIPATE IN FLIGHT. THE APU IS OPERATING ON TAKEOFF UNTIL ABOUT 1000 AGL. ON ARRIVAL MAINTENANCE SAID THEY CAN STILL SMELL ODOR. REPLACED APU WITH AN INSPECTED UNIT AND PERFORMED SATISFACTORY OPERATIONAL AND LEAK CHECKS IAW MM 49-11-01. NO DEFECTS NOTED.