As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT CREW REPORTED AN OILY BURNING ODOR FROM THE AIR CONDITIONING DUCTS. CREW DEACTIVATED THE FWD AC PAC AND THE ODOR WENT AWAY. MX FOUND THE NR1 ENGINE ACCY GEARBOX BREATHER ADAPTOR CARBON SEAL LEAKING. THE SEAL WAS REPLACED AND THE LEAK WAS STILL PRESENT. MX FOUND THAT THE NEWLY INSTALLED SEAL WAS NOT PROPERLY SEATED. THE SEAL WAS AGAIN REPLACED AND SUBSEQUENT ENGINE RUNS PROVED SUCCESSFUL. THE FAULT REPEATED ON THE NEXT FLIGHT.