What was found
DURING CLIMB OUT, PILOT DETECTED FUMES COMING FROM THE CARGO AREA. THERE WAS NO VISIBLE SMOKE, ONLY A BURNING ODOR. THE FUMES CONTINUED UNTIL CABIN WAS DEPRESSURIZED. WHEN THE CABIN WAS RE-PRESSURIZED THE FUMES DID NOT RETURN. AIRCRAFT LANDED UNEVENTFULLY. CARGO WAS INSPECTED DURING OFF LOAD FOR LEAKS, DAMAGE AND UNUSUAL ODORS. NONE FOUND. SUBSEQUENT MAINTENANCE INSPECTION WAS UNABLE TO LOCATE OR DETERMINE THE SOURCE OR CAUSE OF THE FUMES.