As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT THERE WAS A BURNING RUBBER ODOR IN THE COCKPIT AND FORWARD CABIN DURING FLIGHT. THE ODOR DISSIPATED AND RETURNED ON DESCENT. AIRCRAFT LANDED AT DESTINATION WITHOUT INCIDENT. MAINTENANCE REPLACED THE NUMBER ONE RECIRCULATION FAN. OPS CHECKED GOOD WITH NO FURTHER DEFECTS NOTED.